P. annularis hunts mostly in wooded areas and preys primarily on caterpillars from a large number of lepidopteran families, including the Arctiidae, Saturniidae, Geometridae, Limacodidae, Lymantriidae, Notodontidae, Nymphalidae, Sphingidae, Erebidae, Noctuidae, Amphisbatidae, and Elachistidae. They may also hunt flies, moths, butterflies, and other insects. Due to the dominance hierarchy, the reproductive foundress leaves the nest as little as possible, with foraging being done primarily by non-reproductive, worker wasps on her behalf. Only in small nests, with two or three foundresses, the queen may have to forage as well. As soon as the brood of workers emerge as adults, they take over the role of foraging. This prey represents only 20% of food resources; the other 80% is liquid.


P. annularis is a primitively eusocial wasp, meaning that all individuals have the capacity for reproduction, regardless of social caste. Similar primitive eusociality has been seen in bees as well, including sweat bees such as Lasioglossum zephyrus. As such, P. annularis demonstrates behavior typical of other polistine wasps, and has a dominance hierarchy, relatively small colony size compared to yellowjacket species, and a female-biased sex ratio. This dominance hierarchy is due to group competition over scarce resources.|
Dominant females chew on or attach other colony members to demonstrate power, and this higher caste has a propensity for "tail-wagging" and checking cells as compared to the lower ranked workers, similar to behavior in Polistes dominula. A female on the nest will engage the arrival of a wasp from another colony with her antennae, and the clash may last for several minutes and even escalate into grappling. Many of these behaviors are the result of high reproductive competition between females.
The reproductive females, or queens, usually lay the highest percentage of eggs though may occasionally allow subordinates to do so as well. The queens are more active on larger and newer nests. Despite the hierarchy and its dependence on queen size, larger queens do not necessarily inhibit egg laying by subordinates better than smaller queens. However, queens do develop far larger and more developed ovaries than their subordinates, and often have more mature eggs within.
Much of this dominance hierarchy in P. annularis is dependent on dry weight, residue weight, wing length, and fat content. Thus, females from different nests exhibit greater variation in these factors, while females originating from the same natal nest exhibit greater similarity. In atypical cases, the queen may be smaller in terms of these factors than some of the workers on the nest. Generally, wasps that are heavier and have higher fat content have greater ovarian development, with dry weight correlating more heavily with ovarian development than any other parameter. These trends in ovarian development has also been correlated with dominance hierarchy in members of other subgenera, including Polistes gallicus of the subgenus Polistes (Polistes) and Polistes metricus of the subgenus Polistes (Fuscopolistes).


Group nesting through associations is especially prevalent and varied in P. annularis, with an arithmetic mean of between 3.82 to 4.93 and a full range from one to 28. Variation from year to year explains only 2% of the variance in the size of associations. Only 5% of queens run a nest without any co-foundresses, while about three-quarters of foundresses become subordinate to a queen on a cooperative nest. The largest aggregations of foundresses are seen when females reuse the nest in which they were born, typically by constructing a new nest on the old one. In cases where females reuse the natal nest, between seven and eight foundresses are typically active on the nest, as compared to an average of 4.34 for wholly new nests.
The number of foundresses plays a major role in determining the success of a colony. On average, colonies have a 60% success rate for producing workers and 65% for reproductives. However, nests with one foundress are only 20% successful at surviving until workers emerge. Nests with four or more foundresses have an 80% chance of success. Strangely, the inclusive fitness of subordinate foundresses is lower than their fitness in the case where they established a nest alone; it remains unclear why such subordinates do not leave the nest to establish their own.
Selective pressure tends to eliminate any additional foundresses once workers emerge due to multiple factors. Firstly, foundresses compete with each other over the scarcity of space and resources to raise the best offspring. Secondly, workers can perform all the same functions as foundresses with minimal competition. Lastly, workers are more related to their sisters than their own offspring and thus have less incentive to lay their own eggs. These factors together result in the expulsion of the subordinate foundresses, as first observed in the related P. gallicus.
Subordinate foundress mortality significantly increases following worker emergence as compared to mortality rates prior to worker emergence, a pattern also observed in P. exclamans and P. carolina but not in P. bellicosus. Likewise, subordinates decrease foraging rate following worker emergence. However, unlike other polistine wasps, more severe consequences occur for P. annularis after worker emergence, despite this change in behavior. The intricacies of this conundrum remain unsolved though are suspected to deal with senescence as decreased foraging also accompanies decreased aggression. Foundress eviction, as studied across polistine wasps, is independent of the rate of usurpation, which is 9% in P. annularis. In cases when all foundresses are evicted, colony failure rate is high with 19% failing when multiple foundresses are evicted and 80% failing in cases where a sole-founding foundress is evicted. By the time pupae appear, queens are less aggressive towards their subordinates, as compared to when only larvae are present. This behavior of queen eviction has parallels in other social insects, including ants and termites.


In contrast to allied species, P. annularis have a lesser to absent ability to identify their relatedness to other workers to improve inclusive fitness. Instead of beginning spring nests only between the most related foundresses from a natal nest, they do not show any preference for the nest whose members to which they are most genetically related. In cases of sisters born from the same foundress and male pair, the siblings have a relatedness of 3/4. However, sisters that do not share both parents have much lower relatedness. While all of the foundresses of a novel nest come from the same, common natal nest, the workers may choose whichever nest association they wish to join in the spring.
However, P. annularis do possess cuticular hydrocarbons on the surface of their bodies that may serve as social recognition factors. For instance, while males have the same hydrocarbon compounds, the ratio of these compounds differs from females. In males, the dominant component, at 21%, is 3-methylnonacosane. Differences are also known to exist to separate the larvae, dominated by 13- and 15-methylnonacosane at 15%, and the eggs, dominated by 3-methylnonacosane as in the males though at 23%. Additionally,  the lipids in the nest paper probably function in kin recognition among workers.
The matter of sex ratio is related. Within the genus Polistes, sex ratios tend to be biased at 3:1 towards females within northern ranges versus nearly 1:1 in southern ranges. For example, the related P. exclamans, which shares much of its eastern range with P. annularis and has a comparable relatedness between sisters of 0.39, may be a valid proxy in determining the sex allocation patterns of P. annularis. Members of the brood are highly related to the queen, but are less related to the subordinates and their mates, aligning more with a 1:1 sex ratio. As such, it is to the benefit of the wasp to be a reproductive queen as opposed to a worker, if feasible.
In situations where a nest no longer has a reproductive foundress, the remaining foundresses compete for dominance of the nest. These attacks routinely occur and increase over several weeks, during which nest construction and oviposition come to a stop, until certain wasps remit to leave room for a new queen. Often, this successor is the next oldest foundress, due to her size and position in the dominance hierarchy. Following succession, subordinates also may then be chased from the nest. The new queen will lay more eggs than her beta subordinate co-foundresses, inducing the ovaries of other workers to decrease in size, to the point that they will be eliminated following the hatching of new workers. Once a foundress succeeds as the new queen, additional aggression stops; however, if the successor is a worker, aggression tends to rise as the dominance hierarchy has not been well established. Despite aggressions after the removal of a queen, brood care does not decrease.


P. annularis tends to form nests in crowded clumps due to the constraint of suitable nesting sites with overhangs that minimize sunlight exposure, have minimal flooding, and are near a body of water. Consequently, nests often are formed in crowded aggregations on the same overhang. One cost of this crowding is the direct reproductive competition between colonies in the form of usurpation of a colony queen by a female from another colony. As a result, the original queen may be fought to the death, until being banished by the colony, or until becoming a reproductive subordinate. Unlike suggested by selfish herd, no advantage is seen for a colony to be in the center of the aggregation, further from predators. For comparison, the temperate species Ropalidia plebeiana from Australia that also forms nest aggregations tends to gain joint protection from predators for the entire aggregation. Instead, the cost of reproductive competition for colonies in the center of the aggregation is increased relative to colonies closer to the edge. Also, no advantage exists for a new colony to be established in close proximity to its preceding natal colony.


As with many other species in the Hymenoptera, as well as other polistine wasps, P. annularis has been noted to engage in altruistic behavior. For example, despite the lack of drastic morphological differentiation between workers and foundresses, and the benefits procured by a worker becoming a foundress on a new nest, a worker may lay less than 10% as many eggs as her queen, independent of the number of females on the nest. This results in vastly decreased inclusive fitness for the worker and greatly increased inclusive fitness of the foundress, even if the sisters are related by a factor of 0.75, the maximum possible relatedness for outbred sisters. The workers acting in such a manner may create a direct cost upon which selection can act. However, evidence for this has been scant, and researchers are currently investigating why and how such levels of altruism are sustained in P. annularis.


Birds often try to knock nests of P. annularis off of their overhanging, and colonies that hang low toward the ground can be attacked and eaten by raccoons. During the warmer days of winter, wasps returning to their natal nest for honey are exposed to attack from other members of the species, wasps of other species including yellowjackets, and from mammals. However, Polistes species have evolved to hide their nests from most mammals or put them in areas as to make them inaccessible. Invading insects are attacked. Despite the fact that birds are common enemies of polistine wasps, none has been observed attacking nests for honey. The principle predators are ants, so the pedicel of the nest contains lipids that provoke a necrophoric response from ants, protecting the nest from ant invasion. It is parasitized by Elasmus polistis and the moth Chalcoela iphitalis. P. annularis defends itself and its nest from threats with its sting, and the antigen 5 in their venom is a major allergen.


Polistes apachus is a social wasp native to western North America. It is known in English by the common name Texas paper wasp, or southwestern Texas paper wasp. It has also been called the Apache wasp, perhaps first by Simmons et al. in California in 1948. Simmons et al. reported how in California P. apachus is often found in fig orchards where it is considered a pest species due to its aggressive attacks and painful stings on farm labourers during harvest time in September and October. It may sometimes also be found in other types of orchards or in vineyards, but in California it is also commonly found to establish nests in or on houses in urban areas in attics or under the eaves of buildings. It is a type of paper wasp, which is the common name for a type of wasp that uses a papery material to construct its nests.


Polistes apachus was originally named by Henri Louis Frédéric de Saussure in 1857. A phylogenic study by Pickett et al. in 2006 was unable to resolve anything useful regarding the relationships of the different Polistes species amongst one another.
A 1981 study of two nests of P. apachus from a university campus in Texas found that although most specimens had a haploid chromosome number of 22, two specimens in one nest had 25. All P. apachus specimens from these nests and one extra colony were morphologically determined to be the same species. This may be due to two identical cryptospecies sharing the same range, simply a sampling error, or some other form of karyotypic diversity.
It is classified in the subgenus Fuscopolistes according to James Michael Carpenter and Bolívar Rafael Garcete-Barrett (2005).


Polistes apachus can grow to a maximum length of about 20 mm. The ground color is golden brown. As with all or most Polistes species, there is no recognizable difference in size or appearance between egg-laying queens and her workers.


The antennae are entirely a dull orange-brown. The clypeus is practically flat when viewed from the sides.
On the thorax, the pronotum has a thin yellow border, and its metanotum has two transverse yellow stripes. The anterior (front) stripe is narrow and the posterior (back) stripe is broader. There are two longitudinal yellow stripes on the mesoscutum, however some males do not have these stripes, and they are especially absent in populations from Texas.
The abdomen has alternating stripes of golden brown and yellow. There are two prominent yellow spots/patches positioned opposite each other slightly to the sides of the middle (sub-lateral) of the second tergite (a segment of the exoskeleton on the back) of the metasoma, and usually smaller and less obvious spots on the first, third and subsequent tergites. The metasoma of the male has a tubercle in the middle of the seventh sternite.


Like most insects, the genitals of this species are very characteristic. The male wasp has a paramere that is two and a half times as long as wide at the middle, with the parameral spine about 1/8th of the length, and a shallow groove at its side. This spine is covered in short and dense bristles and pointed apically. The paramere lobe is weakly developed and rounded, the lower part of the paramere is narrow, about 4/5 the width at the middle part.
The aedeagus is robust. The apical part of the ventral (inner) edge of the aedeagus is toothed, with the pattern of these teeth like those of a saw, a short tooth followed by a longer one, these extend from the penis valve to the expansion of the middle part of the aedeagus. The lateral margin (edge) of the aedeagus is curved. The penis valve is about 1/3 of the length of the apical (front) of the aedeagus and it is dilated, bi-lobed, and has a clearly distinguishable entrance in the central portion. The expansion of the middle part of the aedeagus is well developed and has a pointed apex. The lateral apodeme of the aedeagus is directed forward with a weak central projection and almost the same size as the ventral process (projection), this process being rounded and slightly expanded at the apex, but slightly constricted in the first part. The inferior (lower) portion of the aedeagus is weakly curved -it appears almost straight when viewed from the side. The aedeagus has about 22 uniformly-shaped teeth ventrally.
The digitus is robust, with a very reduced apical process, and clearly marked punctation over its entire base and short and dense bristles on the base, especially on the lateral edge. The anteroventral lobe is long and pointed at the apex.
The cuspis is robust, covered with short and sparse bristles, and of a triangular shape, with its apex being indistinctly pointed and tapering gradually to the end. There is only punctation on the lateral lobe. The lower part of the cuspis is developed and appears somewhat membranous.


Nests can grow to be large by the end of the season, containing about 150 cells according to Richard Mitchell Bohart and Bechtel, but average nest sizes of up to 320 cells and 13cm in diameter are reported in Californian fig orchards by Ebeling, with a maximum comb size of 15X20 cm. Like all Polistes species, the nests are single-layered and shaped as an umbrella, with the cells exposed to the air from the bottom (no paper layer wrapping around the nest), and are suspended from a petiole.


The taxon Polistes texanus was described from Texas in 1872 by Ezra Townsend Cresson, but is now seen as a synonym. It has sometimes been applied as a form or subspecies that lacks the typical longitudinal stripes on the mesoscutum.
The thickness of the yellow and brown bands of colour on the abdomen can vary amongst individuals. Either brown or yellow can predominate on certain individuals, while other individuals display an equal amount of yellow and brown.
Specimens from Texas, Oklahoma and Kansas seem to vary more in colouration. Some may have completely yellow abdomens. Some may have much more brown colour and lack all of the yellow spots except those on the second tergite. Others may not have the usual pair of thin lateral lines on the pronotum.


P. apachus is the largest and most brightly-colored Polistes in the state of California, which helps with differentiate it from similar species. According to the identification key supplied by Bohart and Bechtel, it is most similar to the other Californian Polistes species P. dorsalis and P. aurifer. These can be differentiated by means of colour, with P. apachus being the only yellow and brown coloured species. P. dorsalis is coloured with black and reddish; P. aurifer is black and yellow, or red and yellow, depending on the color form. The teething on the edge of the aedeagus is furthermore characteristic, and P. apachus has a practically flat clypeus, whereas these other two species have a clypeus which is either convex or concave. P. dorsalis does not share the same range as P. apachus.
P. apachus shares a similar yellow and brown pattern with P. exclamans,  which also occurs in California, but is much smaller, lacks spots on the abdomen, and has males lacking a tubercle on the seventh sternite.


Polistes apachus was collected for the first time in 1856 by the Swiss scientist and wasp specialist de Saussure, who had travelled north from central Mexico into Nuevo México, a vast area spanning from modern Nevada to Texas which the United States had occupied and annexed a few years previously.
P. apachus is found in the United States and Mexico. Bohart and Bechtel believed the Californian population to be disjunct to the rest of the distribution in the east of Mexico and the rest of the US, however this species has been collected in contiguous areas south into Baja California and eastwards in Arizona.


Arizona: It has been found in the counties of Cochise, Gila, La Paz, Maricopa, Mohave and Yavapai. Although the distribution map provided by Bohart and Bechtel in 1957 claimed that the species does not occur in Arizona, there have been abundant collections of specimens in Maricopa County, central Arizona, since 1950 (which were identified as such by Bohart himself). Most, if not almost all, collections in Arizona are in the heavily populated environment around Phoenix and along the state's stretch of the Colorado River, this may be due to sampling bias or may reflect actual distribution and abundance.
California: In 1957 Bohart and Bechtel advanced the theory that this species is not native to California, based upon their series of specimens -the first specimen of this species to have been collected in the state was in the county of San Bernardino in 1921, with subsequent collections in the following years in the surrounding counties: Riverside in 1928, Kern in 1938, San Diego in 1942, Los Angeles in 1943, Fresno in 1944, Merced in 1946, Stanislaus in 1947, Tulare in 1950, Inyo in 1951, Glenn in 1952, and the eventual northernmost county being Yolo in 1954. It has also been recorded at later dates in Imperial County (along the Colorado River) and Orange County. It is thus found primarily in the inland lowlands of central southern California, corresponding to the suburban sprawl and irrigated agricultural areas. Bohart and Bechtel for some reason further theorised that it had come from Texas (possibly unaware of the differentiation in colouration in much of the Texas population). They lastly theorised that it would not spread further north than Yolo, based on their (mistaken) belief that the distribution did not extend north of southern Colorado and Kansas, which was based on the fact that no one had sent Bohart a specimen from north of these areas.
Colorado: Bohart had a specimen from southeastern Colorado. It has been seen in the counties of Prowers and regularly in Boulder since 1917. All the collections in Boulder County were at a high altitude, one to 2641m.
Kansas: It has been found a few times in southern Kansas. It has been recorded in the counties of Kingman, Sedgwick and Sumner.
Nevada: Since 2019 it has been recorded in Clark County in southeastern Nevada.
New Mexico: It is found in much of New Mexico, being recorded in the counties of Bernalillo, Chaves, Doña Ana, Eddy, Sandoval and Valencia.
Oklahoma: It can be seen throughout Oklahoma, with the exception of the eastern fourth or so of the state, having been recorded in the counties of Cleveland, Ellis, Garvin, McClain, Roger Mills, Texas and Woodward.
Texas: It is likely extant throughout Texas, with the exception of the region east of a line drawn between Houston and Honey Grove. It is known from Austin and Bryan–College Station, and the counties of Dallas, Ector, Fannin, Hardeman, Midland, Oldham, El Paso, Potter, Randall, Reeves, Travis and Ward.
Utah: It has been collected in the village of Bluff, San Juan County and recorded in a number locations in Washington County.


Baja California: Found in the municipality of Mexicali in what little is left of the Colorado River Delta.
Coahuila: It has been recorded in the municipalities of General Cepeda, Ocampo (village of Boquillas del Carmen) and Saltillo.
Durango:: It has been found in the municipality of Gómez Palacio (town of San José de Viñedo).
Nuevo León:: It has been recorded in the municipalities of China, El Carmen, General Escobedo (within the metropolis of Monterrey) and General Zuazua.
Tamaulipas: It has been recorded in the municipalities of Río Bravo and San Carlos.
San Luis Potosí:
Sonora:


Polistes apachus often makes its nests in vineyards and orchards, and can also be found in more urban areas. It appears that P. apachus originated in habitats associated with mesquite and grassland more so than wooded areas.


In California the wasps are seen from February through December. These wasps fly slowly with their legs extended and trailing under and behind them. When it is cold, such as sometimes early in the morning, the wasps are more sluggish and slower. They are more active during high daytime temperatures.
This species is often seen drinking water, especially so on hot and dry days. This may be from droplets on plant leaves to sources of open water such as puddles or backyard pools, often standing on water using surface tension.


The queen initiates a new colony in the spring by constructing a nest. One overwintering female generally begins nest construction. Sometimes, a group of cooperative foundresses can work together to build a nest. After nest initiation has begun, other fertile females can join the founding female(s). These cooperating females can help with nest construction and maintenance, but do not always remain in the nest permanently.
The nests are built using wood fibres that the wasps scrap off old weathered pieces of wood. The wasps appear to prefer certain pieces and return to these repeatedly, sometimes congregating on a particular spot.
Nests are often built suspended from branches in the tops of low trees, but are also often built in the eaves of houses, or sometimes in barns or attics.
The area where the nests are located tend to be reused, and foundresses often return to locations near the parental nest site. New nest sites can also be initiated. Ultimately, mature nests generally consist of 20–30 individuals.


Additional fertile females often join founding females, which results in the establishment of a dominance hierarchy within the nest. The queen maintains her role as the only egg-laying individual, while the other fertile females are relegated to worker status. They help in nest construction and maintenance. The dominant queen acts aggressively against females who attempt to lay eggs of their own by eating eggs laid by other females. This behavior can also be observed in the related species Polistes instabilis. If the dominant queen dies, however, one of the other fertile females can take over her duties to ensure the survival of the nest.


Colonies of P. apachus almost always have one female who lays the eggs. Studies indicate that a colony is headed by one queen at a time, but that a single colony sees a succession of queens over the colony lifespan. As a result, the average degree of relatedness between workers and their female brood is less than .5. This suggests that Hamilton’s theory of kin selection does not provide an adequate explanation for eusociality in P. apachus. Though evidence does exist that eusociality is in some ways a result of kin selection, studies reject the evolution of eusociality based on the maintenance of a relatedness greater than .5.


In the wild they build their nests hanging from a branch near the tops of shrubs or small trees, for example Baccharis sp. in New Mexico or Juniperus sp. in Colorado. The adults may be seen drinking nectar from a wide variety of flowering species.
Many species of Polistes prey on caterpillars, which they do not eat themselves, but macerate to serve as a protein-rich juice for their larvae.
A species which may possibly prey on P. apachus is the robber fly Proctacanthus hinei.


Another wasp, Pachysomoides fulvus, is an ectoparasitoid of Polistes apachus and other paper wasps in the United States. Pachysomoides fulvus lays eggs on the larvae of Polistes apachus. This especially affects new nests with only one foundress, as the queen must therefore leave the nest to find food. This leaves the nest especially vulnerable. The nests of this wasp are invaded by the parasitoid caterpillars of the moth Chalcoela iphitalis which feed on the wasp larvae and pupas at night, spinning their cocoons in empty cells. Other known parasites of this species are the strange fly-like creature Xenos peckii, an entomophagous endoparasite, and an unknown species of Sarcophaga fly.


Polistes apachus can sting painfully and repeatedly, and scares children and adults. Exterminators are sometimes called in to eliminate nests. It has established itself in some areas of California as the main Polistes species in urban areas. It often builds its nests under the eaves of buildings. It may also nest in orchards and vineyards. It has been a problem for workers in fig orchards who have often been stung. A number of chemical pest control methods have been tested for P. apachus. Most commercially available aerosol sprays containing pyrethrins are effective at knocking the wasps down to the ground. Dusting nests with 10% DDT has been shown successfully eliminate them. On the other hand, poisoned baits using beef liver and honey have proven to be unsuccessful. One former pest control professional has recommended using a jet of high pressure water to spray them off of eaves,  doing this early in the morning while the wasps are less active, quickly crushing any wet and stunned wasps which fall into the garden, and doing this in the spring before the nests become too big.
With that being said, in some cases some Polistes species may be beneficial to farmers due to their hunting of caterpillars.


As outdoor activity has increased, so too has the nuisance of P. apachus. Its stings can lead to serious allergic reactions in humans and cats. Recent studies have used venom specific detection to determine that P. apachus stings have led to anaphylaxis. Venom immunotherapy (VIT) can sometimes be used to treat allergies to insect stings, specifically in individuals who experience systematic reactions to insect stings. Though the safety of VIT with the honeybee has been questioned, VIT appears to safe for P. apachus venom.


The IUCN has not evaluated this species' conservation status.
It has been recorded as present in the following protected areas:
Brantley Lake State Park (when it was still Lake McMillan), New Mexico, US.
Cibola National Forest, New Mexico, US.
Coronado Historic Site, New Mexico, US.
Hornsby Bend Bird Observatory, Austin, Texas, US.
Kevin Gottshall Memorial Park, Oklahoma, US.
Laguna Grande Restoration Area (just north of the Colorado River Delta), Mexicali, Baja California, Mexico.
Monahans Sandhills State Park, Texas, US.
Petroglyph National Monument, New Mexico, US.
Prescott National Forest, Arizona, US.
Tonto National Forest, Arizona, US.
White Rocks Nature Preserve, Colorado, US.
Zion National Park, Utah, US.


Polistes bellicosus is a social paper wasp from the order Hymenoptera typically found within Texas, namely the Houston area. Like other paper wasps, Polistes bellicosus build nests by manipulating exposed fibers into paper to create cells. P. bellicosus often rebuild their nests at least once per colony season due to predation.


Polistes bellicosus belongs to the subfamily Polistinae, which consists of only social wasps. Polistinae is divided into four tribes: Polistini, Epiponini, Mischocyttarini and Ropalidiini. The tribe Polistini includes the genus Polistes and is the only tribe of Polistinae with a cosmopolitan distribution, i.e. it is the only tribe found in many different global habitats. Polistes bellicosus is most closely related to P. apaches based on a phylogenetic tree.


Along with the genetic similarity, the phylogeny of the larva is also explained using morphological characteristics. Starting at the head, larvae are often dark brown. The body is widest at the anterior part of the abdomen and tapers towards the posterior end. The circular, slender mandible is weakly chitinized. From the mandible extend two or three pointed teeth. Polistes larval mandibles function in opening and closing the mouth for intaking food. Larval mandibles are both longer and narrower than the mandibles of Vespa larvae. Secreted saliva may aid in food-reception for the larvae. Compared to Vespinae, the pleural lobes of Polistinae are less conspicuous.


Males and females have lemon-yellow abdominal segments. Females have a fine, central, longitudinal, black line along the mesothorax, which is transversely wrinkled. The mesothorax in males has two longitudinal lines on the side. Both sexes have yellow mandibles and narrow posterior orbits that are broader toward the bottom. Although caste separations are present in P. bellicosus, females in the colony are not morphologically different.


P. bellicosus generally establish colonies within Texas, though the range has been observed to include North Carolina and Florida. Colonies naturally occur on Baccharis sp., Ilex vomitoria, and Rubus sp. in native prairies at Brazos Bend State Park, near Houston, Texas. Several other paper wasp species—including Polistes exclamans, P. dorsalis, P. metricus, and P. carolina—are found in Brazos Bend State Park due to the multiple types of habitats present, including native shortgrass prairie and oak forest.


The colony cycle of P. bellicosus is similar to many other species of Polistes. Colonies are initiated in March and the cycle lasts eight months. Overwintered females initiate colonies in low vegetation with open-celled nests made of paper fibers. In May, the first brood emerges—consisting of mostly females that usually become workers. The few males that emerge in the first brood mate with workers that eventually leave the original nest to become queens in new nests. The last eggs are laid in late August–September and these males and future overwintering females emerge in late September–October. After a few weeks, the wasps dissociate from the nest to seek shelter for the winter. Some mating may occur in these shelters.
Females all look the same, but they can be divided into four general categories based on role and time of emergence: foundresses, workers, queens, and gynes. Females that have overwintered and then initiated a nest in spring are called foundresses. Foundresses then rear workers, which emerge in the spring and summer. Either foundresses or workers can become queens, which are the principal egg-layers within a nest. Nonworking females that emerge in autumn are gynes.


In colonies initiated by several foundresses, it is common for these co-foundresses to cooperate and rear the young. When this occurs, there is a reproductive division of labor that is based upon a dominance hierarchy. Usually, the foundress that establishes dominance is either the largest or the first to arrive at the nesting site. Within a colony, there is a caste system based on behavioral roles and temporal period. Female roles are divided into queen, subordinate, worker, and gyne. The dominant foundress becomes queen of the nest and the rest of the foundresses become subordinates. A worker could potentially become queen if all of the original foundresses leave the nest and she mates with one of the males that emerged early in the season.


Once a dominance hierarchy is established within a new colony, the queen assumes the responsibility of most of the egg-laying, while the subordinates are responsible for caring for the young. The workers are also responsible for caring for the brood and enlarging the nest. The distinction between workers and gynes is that gynes are only produced late-season and workers emerge throughout the reproductive period. In addition, gynes are inactive in the nest. Gynes mate before overwintering and, if successful, become foundresses for the next season.


Most workers in Polistes remain in their natal nests and function as helpers. In all but a few species of Polistes, females that emerge mid-season function as helpers until the queen is no longer present. Significant variation in helping is found in foundresses of different species of Polistes. Within a nest, cofoundresses are found to be more than 50% related. The degree of relatedness between the cofoundresses may explain the benefit of joining a nest as a subordinate rather than developing a separate nest with a lower chance of success. Subordinates contribute labor toward the care of the dominant foundress’s offspring and decrease the foundress' mortality by taking over the more dangerous foraging labors.


Foundresses attempt to establish new nests every spring. Paper wasps are often expected to select nest sites that were successful in previous seasons. When foundresses attempt to establish nests in new sites, there is the possibility that the site is disadvantageous to colony initiation. Foundresses who do not succeed in initiating a nesting site alone often, out of necessity, join another colony as a subordinate. The foundresses typically join the nests established their sisters. Foundresses that must join established nests enter as subordinates, but do not differ in size than successful foundresses.


The likelihood of foundress death increases at a constant rate the more time she spends away from the nest. Once the first workers emerge in late spring, the foundresses no longer leave the nests and the foundress death decreases significantly. This suggests that foundress death is associated with tasks that occur outside of the nest—such as foraging for food or other resources. In instances where the foundress dies outside the nest, likely due to predation, the brood is left defenseless and is observed to die of starvation. Furthermore, errors in nest site choice likely contribute to foundress mortality. Previously successful nest sites are typically better than new sites. As a result, foundresses that attempt to establish nests in new sites have a higher chance of mortality.


Polistes bellicosus does not directly follow the Hymenopteran haplo-diploid genetic system where female workers are more related to their sisters (0.75 degree of relatedness) than to their own offspring (0.50). The relatively lower level of relatedness could be explained either by multiple mating—queens mating with more than one reproductive male—or by the presence of multiple egg-layers within a colony. Kin selection theory states that selection favors individuals who act altruistically when the ratio of the cost of the fitness of the giver to the benefit of the recipient is less than the degree of relatedness between the two individuals. In P. bellicosus, foundresses aid fairly close relatives instead of individuals that are unrelated, which explains variation in helping within species.


Like other species of the genus Polistes, the queen is the primary egg-layer and the subordinates typically do not lay many eggs. However, the subordinates are capable of egg-laying and do so only when the queen is absent. In many cases, potential queens join established nests and become workers and tend to the brood. Often these workers have to submit to aggressive attacks by the queen. If the queen is successful, the workers continue to serve their role and tend to the brood and do not lay eggs. Despite behavioral castes, all females are morphologically similar. Therefore, any female can produce eggs and has the potential to become a queen, regardless of caste level.


Predators are known to knock down and remove entire nests to eat the larvae inside. In the case of ant predation, the ants overwhelm the nest and only frayed remnants are left. However, ant predation in P. bellicosus is observed to be much less common than predation by vertebrates. Among possible vertebrate predators are birds, raccoons, and opossums. Predators either remove the nest whole or in large, broken pieces. The long colony cycle—from spring to late autumn—along with the common predation often requires that the wasps create a new nest at least once during a season. In addition, the chances of a nest being removed or destroyed do not decrease with size of the colony. Thus, larger colonies are at equal risk of predation as smaller colonies.


Polistes carnifex, commonly known as the executioner wasp, is a neotropical vespid wasp in the cosmopolitan genus Polistes, known for its extremely painful and potent sting.
It is a very large yellow and brown paper wasp with a mandible that contains teeth. It establishes small colonies, founded by solitary queens, which build nests under the eaves of buildings or suspended from branches. Foraging adults bring nectar and macerated prey back to the nest to feed to the developing larvae which are individually housed in separate cells in the nest.


As its range includes only small portions of the English-speaking Americas, P. carnifex has only recently taken on an English vernacular name, but in the mid-2010s the name executioner wasp was proposed, a calque upon the Latin specific name carnifex "executioner, hangman". This name, and the species, were subsequently widely popularized by YouTube personality Coyote Peterson in a 2018 video describing the wasp's painful sting.
In Paraguay, it is usually known in Guaraní as kava mainomby "hummingbird wasp", in reference to its great size; less commonly it is called kava alazán "brown wasp" (more usually P. cavapyta), or kava sa'yju "yellow wasp" (more usually Agelaia multipicta or A. pallipes). In the Mexican state of Guerrero, speakers of Malinaltepec refer to the executioner wasp and the closely-related P. instabilis as a’ma xtíya cháda "huarache-nest wasp", alluding to the flattened shape of the nests they build.


In 1768 the HMS Endeavour left Plymouth on the first voyage of James Cook, reaching the harbour of Rio de Janeiro a few months later, in November. Here one of the passengers, the wealthy naturalist Joseph Banks, procured a female specimen of giant wasp, which made its way around the world to eventually arrive in England in 1771.
Meanwhile, the Dane Johan Christian Fabricius had travelled to Uppsala University in 1762 to study under the celebrated Carolus Linnæus, and upon returning to Denmark two years later began to work on his first publication, the Systema Entomologiæ, in which he attempted to list all known species of insects (which included spiders, crabs and other arthropods at the time) according to the new Linnaean system. By 1770 he had been appointed professor at the University of Copenhagen, and when in 1773 the University of Kiel (now German) had been ceded to Denmark, he was soon appointed professor there. By 1771 Fabricius began making yearly summer trips to London to study the collections that Banks and others had made in foreign lands, where he was able to study Banks' Brazilian specimen of wasp at Banks' London residence. In 1775 the 832 pages of the Systema Entomologiæ were finally published, and in this Polistes carnifex was scientifically described for the first time under the name Vespa carnifex, using Banks' specimen as holotype. This specimen is now stored at the Natural History Museum, London.
In 1802 Pierre André Latreille created the genus Polistes, and in 1804 Fabricius moved this species from Vespa to the new genus.
The authority citation of the species has erroneously been attributed to Henri Louis Frédéric de Saussure, who wrote some of the most important books on the subject of wasps.
In 1853 de Saussure recognised that numerous taxa which had been described by others were synonyms of this species, and synonymised P. onerata, P. rufipennis, P. transverso-strigata and P. valida with P. carnifex. He also synonymised P. chlorostoma and P. major to it, although both are now recognised as valid species.


Owain Richards in 1973, and again in 1978, classified P. carnifex in a monotypic subgenus he named Onerarius. In a 1996 morphological study of most of the genus Polistes, James Michael Carpenter found this subgenus to cause the subgenus Aphanilopterus to be paraphyletic, and therefore synonymised Onerarius with the subgenus Aphanilopterus. However, by 2018 he no longer followed his own taxonomic interpretation and continued to use  Richards' Onerarius.
In 1857 de Saussure was the first to attempt to organise the American Polistes species, doing so on the basis of the form of the abdomen -either conical, with the first segment broad, and tapering to a compressed last segment, with a conical and somewhat elongated metathorax; or with the abdomen oval-shaped, the first segment ampulliform (shaped like a flask) and the metathorax more flat and its end less elongated. He placed P. carnifex in a third group with characteristics in between these two, together with P. aurifer and a new species he described from Nuevo México (a Mexican territory which had recently been conquered and annexed by the USA and at the time included everything in between modern California to east Texas), P. comanchus.
Among the species of Polistes which occur in Pará, Adolpho Ducke groups it with P. canadensis, P. goeldii and P. versicolor, based on the morphology of the mesopleuron.
One of the hypothesized phylogenetic trees puts P. carnifex most closely related to P. major and more distantly related to the following species: P. apachus, P. aurifer, P. bellicosus, P. carolina, P. metricus, P. poeyi ssp. haitiensis and P. perplexus. However, there has not been a consensus with regard to the phylogeny of P. carnifex so no one phylogenetic tree can be termed correct.


The following three subspecies are accepted:
Polistes carnifex ssp. carnifex - found in eastern Brazil, Costa Rica, Mexico and the USA.
Polistes carnifex ssp. boliviensis Bequaert, 1936 - found in Colombia, Peru and Bolivia.
Polistes carnifex ssp. rufipennis (Latreille, 1833) - found in Honduras, Panama and Venezuela.
The holotype of P. carnifex ssp. boliviensis was collected by José Steinbach somewhere in Santa Cruz Department, Bolivia. It and three paratypes from Bolivia and Peru are stored in the Museum of Comparative Zoology, Harvard University.
P. carnifex ssp. rufipennis was originally described as P. rufipennis by Pierre André Latreille from a collection made by Alexander von Humboldt and Aimé Bonpland during their celebrated journey of scientific exploration to the Americas. The single female specimen (the holotype) was collected somewhere in Venezuela. It was synonymised with this species by de Saussure in 1853. See the section "Description" below for more on this subspecies.


Polistes carnifex is the largest Neotropical wasp in the genus Polistes with a body length up to three centimetres. The normal size is 24-27mm, with a possible maximum of 33mm. Despite its size, it is a relatively non-aggressive insect.
It is colored yellow with some brown stripes, these are partially blackish. The antennae are yellow with a darkened base. The head is yellow, the crown of the head being black and ending with reddish-brown stripes. The maxillae are reddish-brown, outlined in black. The thorax is yellow, the dorsal part black, but with a quartet of dark reddish-brown spots. The pronotum is totally or almost totally colored yellow. The abdomen is yellow, the second segment (tergite) darkened at the base. The wings are reddish-brown, or yellowish reddish-brown, and the feet are dark-colored.
It can be grouped with a number of species which can be distinguished from other species within the genus Polistes by their lacking of a groove on the underside of its head called the epicnemial sulcus. P. carnifex can be distinguished among this group of wasps by its wide cheek plates. Also the first tergite is very compact, dorsally convex, and elevated vertically compared to the constriction where the abdomen is inserted into the thorax. Furthermore, the eyes do not touch the clypeus. Lastly, this is a very large wasp, with individuals always longer than 20mm. The first gastral segment (sternite) is less broad than long.
Ducke states that the nests, with their relatively long and strong central petiole, are characteristic for the species, at least among the species in the genus of which the nest was known in his time.
P. carnifex ssp. rufipennis appears to differ from the nominate type by the body and wings being colored a tan brown, almost chestnut. Latreille describes it as such, with the antennas and the last quarter of the tarsi being more yellowish. It is yellow above the jaws, the posterior (back) edge of the first segment of the thorax, the very end of the thorax, the area beyond the second scutellum, the posterior edges of the first three rings (tergites + sternites) of the abdomen and the entirety of the following ring, this yellow being in the form of bands on the front rings, and forming two large, united patches which extend laterally to the extreme end of the thorax. A part of the inferior and anterior sides, the outline of the scutellum, and the square segment above that which Latreille calls the "second scutellum" are a similar color, but fainter. The abdomen and wings are glossy. The length of the body of the creature is 26mm.


As a member of the order Hymenoptera, Polistes carnifex has mandibles, which may be used to obtain wood fibers, build nests, or capture and macerate prey. The mandibles of P. carnifex are short. Yet, they are markedly wide at their base, with a length to basal width ratio of approximately 2:1. An external basal area stretches "from the basal margin ... to a point situated about half-way the mandible's length."  P. carnifex also have teeth. "A convex distal posterior area ... is continuous with the posterior-most apical tooth and stays adjacent to a distal media area".  This area is convex in P. carnifex. In P. carnifex, the third tooth's anterior edge is elongated, compared to in other species.


Like most insects, the genitals of this species are very characteristic. The male wasp has a paramere that is two and a half times as long as wide at the middle, with the parameral spine about 1/6th of the length, and a shallow groove at its side. This spine is covered in very long and dense bristles and pointed apically. The paramere lobe is well developed and rounded, the lower part of the paramere is narrow, about 2/3 the width at the middle part.
It has a slender aedeagus, with about 27 teeth distributed from the end to beginning of the expansion in the middle part of the aedeagus. The penis valve is weakly dilated, with a central entrance and a weakly bi-lobed appearance (the valve being a little more than 1/3 of the length of apical part of the aedeagus). The expansion of the middle part of the aedeagus is well developed and has a pointed apex. The lateral apodeme of the aedeagus is directed forward with a weak central projection and shorter than the rounded ventral process (projection), while the inferior (lower) portion of the aedeagus is weakly curved -appearing almost straight from the side.
The digitus is slender, with a well-developed apical process which is about one and a half times longer than the base of the digitus and the same width from the base to the end. This end (apex) is pointed. The digitus has a band of obvious punctation around its base, and an anteroventral lobe that is short with a rounded end, and is covered in easily rubbed off (evanescent) bristles.
The cuspis is slender, with an apex which is pointed and tapers abruptly, and covered in long and sparse bristles, with more bristles found at the edges of the sides, and with short bristles on the lower part. The punctation on the cuspis is only found on the lateral lobe.


In Paraguay, according to the identification key provided by Bolívar Rafael Garcete-Barrett, the most similar species are P. cavapyta, which has a completely yellow head and is banded with a rusty orange color, P. lanio, which has extensive black coloration on the mesosoma (~thorax) and back of the metasoma (~abdomen), P. canadensis, which has a red metasoma except some black in the sutures between the plates of the exoskeleton. The much smaller P. major is the only species in Paraguay with a similar color pattern.
In Nicaragua, according to the key provided by Jean-Michel Maes, it is best distinguished from the most similar species of the region, P. major, by its wide cheek plates, and the male genitals of both species are furthermore very characteristic.
In Brazil, Ducke compares it to P. claripennis, which has a similar coloration, but with a more pale yellow. This species is much smaller and lacks the wide cheeks of P. carnifex.
According to Joseph Charles Bequaert in 1936, many of the specimens labelled as P. carnifex in collections are P. major, these two species being commonly confused. All published records from Cuba and Hispaniola are P. major. See for example the description by William J. Fox of a specimen collected on San Esteban Island in the Gulf of California, Mexico.


Polistes carnifex is native to Central and South America; its range extends from Arizona and southern Texas to Misiones Province in northern Argentina. In 1907 Ducke stated the species occurred in the Greater Antilles, but according to Bequaert in 1936, the species does not occur in the United States nor the Greater Antilles. In 1940 he was proven wrong however, when the first specimen from the United States was collected in Arizona by John J. duBois, this record first being published in 1955.
In Brazil it has been found in the states of Rio de Janeiro, Pará and Paraná.
In Mexico it has been recorded in the states of Baja California, Guerrero, Jalisco, Morelos, Nayarit, Oaxaca, Sinaloa, Sonora, Veracruz and Yucatan, as well as Mexico City.
In Paraguay it is found in the departments of Alto Paraná, Canindeyú, Paraguarí and San Pedro.
Bequaert states the species is not common anywhere. Ducke also states it is infrequently seen in Pará, Brazil.


The species is found in coastal, humid, and open areas, such as in evergreen tropical forests. In tropical zones like Paraguay, Brazil and Argentina it is found in extensive wooded habitats without heavy rains.


Before the 1970s little was known of the biology or behavior of Polistes carnifex. P. carnifex is a species of paper wasp, thus, like other members of the subfamily Polistinae, it is an eusocial wasp.


The nest is founded by a solitary queen which builds first cell and then further cells from macerated pulpy material. To create a colony, the queen enlarges a cell by introducing a ball of recently macerated pulp on her own. Using her mandibles, the queen loads the ball while holding the sides of the wall being constructed with her foretarsi. While completing this task, the queen moves her antennae in circles about her head, touching the parallel-lying opposite wall. The antennae-wall contact allows the queen to construct straight sides on the inner wall. She lays eggs and feeds the larvae, feeding them nectar and macerated prey. The female workers that emerge from the first cells then assist with the further building and development of the colony, and can themselves mate and lay eggs.
Polistes carnifex is a social species and the nests consist of a number of horizontal papery cells in which the young are reared. The nests are built from wood pulp which the wasps chew into a plaster. In a study in Costa Rica, nests were found hanging from branches of various species of low thorny trees near an ephemeral swamp. Nests have been seen under the eaves of buildings. The nests are hanging and open-faced, supported by a single Petiole in the centre which is strengthened by a tough gelatinous material. Of the six nests measured by Corn, the maximum size for a nest of P. carnifex was approximately 9 cm in diameter. One nest in which one emergence at minimum occurred had an average length of 27.8 mm. Nests range in the adult population from 4 to 13 individuals. In one nest studied, there were 28 cells and this number remained constant for the duration of the observation (17 days). There was only one cell observed as being enlarged, which was on the periphery.


Of six nests examined in 1972 not all nests contained a female with "well-developed ovaries".


The English naturalist Thomas Belt observed how a Polistes carnifex wasp which had found a large caterpillar, chewed it up and made half of it into a macerated ball. Picking this up, it hovered for a few seconds and then circled several times round the place among the dense foliage where the other half of the caterpillar lay. It then flew off but returned a couple of minutes later and quickly located the correct hole among the leaves. Making its way in among the foliage, it could not at first find the exact leaf on which the caterpillar lay. After several fruitless hunts interspersed with short circling flights, it finally located the dismembered prey and flew off with its trophy. Belt marvelled that the insect could use a mental process so similar to that a human might have used to remember the specific location of its prey.
In Colombia, twenty-nine foraging wasps were observed returning to a particular nest with twenty-five loads of nectar, three loads of macerated prey and one of nest-building pulp. When a foraging wasp arrived, the highest ranking wasp present demanded food and then both fed the larvae. Each wasp pushed its head into a cell, drummed on the cell walls with its antennae and then deposited the food. The drumming noise could be heard a meter away by the researcher, and may have alerted the larvae to the presence of food.


As a member of the order hymenoptera, Polistes carnifex is subject to worker policing. While the diploid female workers do not mate, they are able to lay unfertilized eggs that will develop into haploid males. The relatedness of a worker to her offspring is r=0.5, and her relatedness to the queen's sons is r=0.25. Similarly, the queen's relatedness to her own offspring is r=0.5, whereas the queen's relatedness to her workers' sons is r=0.25, thus the queen prefers to bear her own sons. The other workers are more closely related to the queen's offspring than to their sisters' offspring. The consequences of these differences is as follows: queens try to suppress the production of eggs by workers and workers have an incentive to suppress other workers from producing eggs. This phenomenon is known as "worker policing".


In Costa Rica, male Polistes carnifex congregate on the top of ridges where they maintain territories. The males chase away other conspecific males from these territories which consist of groups of trees and shrubs with no nests. It is suggested that females only mate with males occupying such territories.


Nests (hanging from low branches on thorny trees near a swamp) were sometimes found within about a meter of nests of a Polybia species and occasionally in similar close proximity to a Mischocyttarus nest. Polybia and Mischocyttarus are often associated in the same area; however, Polistes carnifex only occasionally was found in proximity. The association of P. carnifex with other species of social wasps has not been reported outside of Costa Rica. Some trees bore several nests of different wasp species while many other similar trees bore none, which suggests that there is a non-random distribution.
The species P. major appears to be a Batesian mimic of this species.


In a study of six nests of Polistes carnifex, in three cells there was an additional egg instead of the usual one, but these eggs appeared to be of P. carnifex. The author of this study found no evidence of parasitism, however, the wasps are indeed parasitized by strepsipteran insects in the genus Xenos. These obligate parasites infect the developing wasp larvae in the nest and are present within the abdomens of female wasps when they hatch out. Here they remain until they thrust through the cuticle and pupate (males) or release infective first-instar larvae onto flowers (females). These larvae are transported back to their nests by foraging wasps.


Although not a particularly aggressive wasp species, it has garnered a reputation in many Latin American countries for its potent sting. The YouTube personality and wildlife educator Nathaniel "Coyote" Peterson has deliberately exposed himself to a variety of stinging insects for entertainment and educational purposes, and declared that the executioner wasp's sting is the most painful he has ever received, more painful than that of the bullet ant or the Asian giant hornet. Labeling it the "King of sting" in his video journey of the most painful stings from various insects. Peterson also said the sting can cause tissue necrosis around the site of the sting, saying, “My arm was swollen for days, and eventually a small hole rotted in my arm from the venom at the sting site."


The IUCN has not evaluated this species' conservation status.
It has been recorded as present in the following protected areas:
Shipstern Conservation & Management Area, Belize.


It was described in 1857 by Henri Louis Frédéric de Saussure using a collection from Nuevo México - this does not correspond to the modern state of New Mexico, but at the time was a formerly Mexican territory which had recently been conquered and annexed by the USA, and included everything in between modern Nevada to east Texas. He had travelled to this region in 1856.
In 1978 Owain Richards classified P. comanchus in a subgenus he named Aphanilopterus after an old synonym of P. lanio by Fernand Anatole Meunier, he further placed it in a "species group 1".


Two subspecies are accepted:
Polistes comanchus ssp. comanchus - Found in southwestern Texas, Coahuila, Durango, New Mexico?
Polistes comanchus ssp. navajoe (Cresson, 1868) - Found in Arizona, California, New Mexico, western Texas, Sonora, Chihuahua, Durango, Sinaloa. This subspecies makes its nests in cavities reached via a very small opening.


The IUCN has not evaluated this species' conservation status.


Polistes exclamans, the Guinea paper wasp, is a social wasp and is part of the family Vespidae of the order Hymenoptera. It is found throughout the United States, Mexico, the Bahamas, Jamaica and parts of Canada. Due to solitary nest founding by queens, P. exclamans has extended its range in the past few decades and now covers the eastern half of the United States, as well as part of the north. This expansion is typically attributed to changing global climate and temperatures. P. exclamans has three specific castes, including males, workers, and queens, but the dominance hierarchy is further distinguished by age. The older the wasp is, the higher it is in ranking within the colony. In most P. exclamans nests, there is one queen who lays all the eggs in the colony. The physiological similarities between the worker and queen castes have led to experiments attempting to distinguish the characteristics of these two castes and how they are determined, though males have easily identifiable physiological characteristics. Since P. exclamans live in relatively small, open combed nests, they are often subject to predators and parasites, such as Chalcoela iphitalis, Elasmus polistis, and birds. P. exclamans have defense and recognition strategies that help protect against these predators and parasites.


Polistes exclamans is part of subfamily Polistinae within the hymenopteran family Vespidae. Polistinae (paper wasps) is the second largest of six vespid subfamilies, containing around 950 species, and is composed entirely of social wasps. It is made up of four tribes; P. exclamans is part of tribe Polistini. Genus Polistes is currently split into four subgenera that are distributed across the world; P. exclamans is a part of the New World subgenus Aphanilopterus and is most closely related to P. annularis, P. buysonni, P. canadensis, P. lanio, P. cavapyta, P. simillimus, P. crinitus, P. versicolor, and P. instabilis.


There are two forms of Polistes exclamans in the United States: typical and variable. The typical form is found in the south-eastern United States and inhabits the following states: North Carolina, South Carolina, Georgia, Alabama, Florida, Texas, Louisiana, Oklahoma, Arkansas, Kansas, Colorado, and Arizona. Although this form's color can vary, it almost always has some yellow coloring. Both the propodeum and the mesonotum are marked with yellow. The propodeum normally has four yellow stripes, whereas the mesonotum has yellow lines. It also may have yellow markings on its head. The wings, however, are not yellow in color or yellow tinged like some other wasps but are infuscate and purple in color. The typical form often can be confused with Polistes fuscatus, Polistes crinitus, or Polistes minor. The variable form is red-brown in coloring. The middle of the flagellum, the base of the abdominal segments, and the outer side of the mid and hind tibiae are infuscate or black colored, as are the wings. Instead of yellow markings, the variable form has pale ivory-white markings that are dispersed throughout the body. P. exclamans have antennae banded with red, black and yellow, while most paper wasps only have one antennae color. In females, the fore wing length can range from 13.0 to 16.5 mm (0.51–0.65 in) and in males the fore wings can range from 12.0 to 15.0 mm (0.47–0.59 in). The extent of ferruginous (rust-colored) markings is variable.
Although no distinguishing structural features have been found to separate the workers and queens, the male is easily identified by its bulging eyes, subquadrate clypeus, and slender antennae. P. exclamans males are also more variable in external morphology compared to females. This is possible given the male's hemizygosity (females are homozygous).


Polistes exclamans is distributed throughout the United States in the following areas and states: New Jersey down to Florida, Florida to Texas, and west to Nebraska, Colorado, Arizona, and California. It has also been found in Mexico and the Bahamas,  as well as Ontario, Canada.
As a vespid wasp, P. exclamans nests are typically made up of paper with a single layer of cells with open combs. Although nest size varies, the upper limit is around 500 cells. Although many vespid wasp nests have an outer envelope of paper, P. exclamans nests do not. As indicated by Strassmann and Orgren, “Nests are approximately circular, and have a single off-center pedicel [basal part] usually located towards the top of the nest. Cells near the pedicle are the oldest.” P. exclamans are particularly able to colonize new sites, as foundresses often disperse into new territories. P. exclamans have often been found to have nests located near man-made structures and tend to more readily build nests in and near these man-made structures. Out of six wasp species, P. exclamans was the only one that occupied artificial nesting sites. It prefers well-lit, open sites.
Polistes nests can be built from wood fiber which are collected from posts and plant stems. The fiber is formed into a paper-like comb with hexagonal cells. The nests are orientated downward and are held up by one filament. P. exclamans have also been observed occupying artificial nests put out by researchers and consisting of bundles of straws.


The colony cycle of Polistes exclamans is longer than that of northern wasp species, shorter than that of tropical wasp species, and as such is in “some respects intermediate between” the two. Their cycle occurs between March and September. The first brood of workers emerges between May and July. It takes about nine to fourteen days for eggs to develop, though eggs in smaller nests and that are laid later in the season take much longer to develop, about thirteen to eighteen days for larvae to develop, about thirteen days for pupae to develop, and about a total of six to eight weeks for an egg to develop into an adult. Reproductive wasps emerge later in August or September.


Polistes exclamans lives in a hierarchical society with one queen that lays the eggs. However, all of the females have the same morphology and they all have the physiological capability of taking over the egg laying if necessary (e.g., due to queen death or queen migration). Since the queen has the same morphology as the rest of the workers in the colony, this raises the question as to how the queen role is assigned and what makes her special. Studies have found that queens and males have higher levels of glucose, fructose and trehalose than workers, leading to higher cryoprotectant levels. P. exclamans use these sugars as cryoprotectant, which work by increasing the solute concentration in cells. This results in a greater survivability in colder weather. It was found that queens have a 76% survival rate in 5 °C (41 °F) weather compared to 17% survival of the workers over a 15-day test period. The queens also have a 0.5mm layer of fat surrounding their bodies. This allows them to live longer into the winter and possibly extend their mating season. The queens seem to be the only ones capable of diapause.


While there aren't many external morphological differences between queens and workers, there are some internal traits that can be signals of a wasp's social status. It has also been found that caste determination is irreversibly determined by temperature during the immature stages of development. In one experiment, some wasps emerging in June were kept in long day chambers, or chambers set at 26 °C with 16 hours of light and 8 hours of darkness. These individuals had larger and more active ovaries as compared to those who were incubated in short day chambers, which are set at 22 °C with 14 hours of light and 10 hours of darkness. It is thought that this phenomenon may occur because of a juvenile hormone secretion that determines the castes and a suppression of the workers’ ovaries by environmental or hormonal factors.


Given that Polistes exclamans nests are often destroyed or suffer through the death of the queen (most often through natural circumstances), it is necessary and adaptive for there to be a specific system for the replacement of the queen. The current system in place can best “be described as gerontocracy.”  Furthermore, it is also closely related to the dominance system within the colony as well. In the dominance hierarchy, older individuals are higher in rank, whereas younger individuals serve in the lower ranks. These older female workers are generally more aggressive and forage more frequently. In reflection of this dominance ranking and the behavior of the female workers, it is seen that when a queen is no longer present in the colony, the next eldest worker becomes the new queen. This may be due to the genetics of the next eldest queen, as the replacement queen affects the overall relatedness of the females in the brood, thereby allowing the future brood to be more related to the adult workers rearing them.


P. exclamans tend to have smaller nests than other wasps, with typically fewer than one hundred individuals in a given nest. Because of the size of the nest, the queen tends to be the most active individual in the nest. This is because the queen has to monitor and directly control the activities of the nest. In addition to her reproductive role, the queen must also act as the pacemaker of the nest and synchronize the worker activity. However, these last two points have recently been disputed and the workers may be self organized. It has also been observed that the queen will act aggressively towards individuals that are the least active.


P. exclamans are haplodiploid insects, as are other Polistes species including Polistes metricus, Polistes dominula, and Polistes annularis. This means they have haploid males that produce identical haploid sperm, and diploid females that produce haploid eggs through meiosis. This has consequences for genetic relatedness within colonies, since sisters receive identical sperm if they share a father, and the normal half identical contribution from the mother. This results in sex-biased conflicts between the queen and the workers with respect to the sex ratio, with workers preferring a more female biased sex ratio, and queens preferring equal investment in queens and males.


In Polistes exclamans, equal sex ratio is obtained when only 46.3% of investment is devoted to females as female wasps are 1.16 times larger than male wasps. In a study done by Strassmann, it was found that sexual investment is female biased, especially during years of high predation and when nests are generally less successful. It has been seen that in Polistes exclamans, females are produced before males. This female investment bias may result from the ability of females to become either a worker or a reproductive (this is more adaptive for the nest as it gives the nest increased flexibility compared to that of males and may be important for overall nest success) or because females provide the colony with greater nest defense. Even when the original queen is no longer present, the sexual investment is still biased towards females, which is not expected given the genetic implications of a new queen.


Workers first emerge between May and July. During this first emergence, reproductive males also emerge with this first brood and are called the "early males". These males provide a great adaptation because they allow for the presence of reproductive males. Nests with a greater number of early males produce a greater number of workers, cells, pupae, and emergences. Although it is uncertain as to why, queen deaths are common in Polistes exclamans, most frequently in May. The majority of original queens are dead by July, “well before eggs that became autumn reproductive were laid,” as reproductives emerged from late August through September. Thus, queens must remain alive post June in order to birth future reproductives, and if they are not able to do so, the eldest former worker then becomes the new queen. The reproductive early males produced may be adaptive for the deaths of the queens so that the colony will not die and will be able to continue.


As with many other insects, P. exclamans use sexual pheromones to attract members of the opposite sex. Researchers have attempted to determine the exact role that sexual pheromones play in sexual attraction in paper wasps. In one experiment, they set up a wind tunnel where males and females were exposed to a sexual pheromone wick that was isolated from males and females. These pheromones were taken by hexane extracts from whole bodies and thoraces of unmated females. The male extracts were taken from the ectal mandibular and seventh sternal glands. It was found that the opposite sex was attracted upwind of the scent and the results were intensified when a fan was turned on. The range of the scent was found to be around 2 metres.
In nature, it was observed that males would venture away from the nest in order to attract females. The males would press their gastral sterna against a perch and rub their mandible against it. This is used to attract females, and females were observed to visit these branches and sample the scents. It was also found that on some occasions, males were attracted to other male scents.


Polistes exclamans have comparably smaller nests and colonies compared to certain other eusocial wasps species. Thus, it is common for the nest to be destroyed, for the queen to die prior to the end of the season, or for the nest to fail through other means, such as predation, parasitisation, or worker mortality, leading workers to help rear broods that are less related to them than are their sister wasps. Due to this, it would be advantageous for there to be wasps that remain casteless till adulthood, allowing female wasps’ reproductive capabilities to be plastic. It has thus been predicted that P. exclamans worker wasps would act as workers if a brood were present and would begin to develop gyne characteristics if a brood was not present, exhibiting the aforementioned adaptive plasticity. Experimentally, this has been found to be true. Solis and Strassmann conducted a study in which an experimental group had the eggs and larvae removed. In the experimental group, the wasps began to behave like future queens and even developed the characteristic layer of fat common to queens. In the control group, the wasps continued to behave as workers. This is indicative that the presence of the brood affects caste differentiation and that P. exclamans female workers exhibit adaptive reproductive plasticity.


Nest mate recognition is widespread in many eusocial insects. However, when there are no physical differences in either diet or nesting materials, many can no longer discriminate nest mate from other conspecifics. Recently, however, it has been indicated that many insects have the ability to discriminate relatives even having lived in identical environments with their non-relative counterpart. Studies have indicated that in Polistes fuscatus, former nestmates would nest in areas located close together near their natal nests the following spring. Social halictid bees also are able to recognize their relatives. In P. exclamans, it has been indicated that discrimination of relatives from non-relatives, even having lived in identical environments, is possible. This was found by Allen, Schulze Kellman, and Gamboa through an experiment in which hibernating wasps from different nests were put in a box together after being raised in identical environments. As the number of unrelated groups of wasps increased, the more clumps were formed in the box. This indicates that the wasps were capable of differentiating relative from nonrelative, an adaptive ability in the defense of their nest.


Many Polistes species aggregate over winter. P. exclamans clump in rather large aggregations while hibernating. “These aggregations are frequently found in protected places called hibernacula that can be as varied as crevices and cracks of rocks or trunks, beneath the bark of trees, between walls of buildings, or any other natural or artificial structures that provides protection during hibernation.” Although P. exclamans have been found in organ-pipe muddauber nests, a mud nest that can provide a certain level of protection, it is not thought to actually house hibernating P. exclamans over the winter.


A typical P. exclamans worker will live somewhere between 14 and 16 days. The oldest wasp to be observed in a natural colony was 102 days old. Queens typically live 6 times longer than the workers. There has been some variation observed with the life expectancy of P. exclamans. This has typically been attributed to the colony of origin. It also must be noted that while there is variation between colonies, there typically is less variation between the original nest and the satellite nest. Variation inside a single colony may also occur because of the presence of different castes. Foragers, those who frequently travel outside the nest, lead a riskier life and tend to have lower life expectancy than those who stay in the nest. Still, it was observed that colonies with high foraging rates also had higher reproductive rates to compensate for the lower life expectancy. Another aspect, observed in one nest, was that an increase in female population led to lower longevity. This was because the females were more focused on competing to become the next queen than foraging and fulfilling their roles.
Worker death is an important factor in colony failure, and is the cause of 13–76% of colony failures. This may be in part due to the small colony size. Because the colonies are small, worker longevity is crucial for the survival of the nest.


Throughout the 1950s and 1960s, P. exclamans was extending its range, spreading into the midwestern United States. Between 1958 and 1967 the following states had new state records of P. exclamans: Illinois, Indiana, Kentucky, Maryland, Missouri, New Jersey, New Mexico, Tennessee, and Virginia. The behavioral basis behind range expansion could be based upon the exceptional capability P. exclamans has in the colonization of new sites and the solitary nest founding behavior P. exclamans exhibits. This capability could be assisted by the “associated tendencies of P. exclamans foundresses to disperse and to move into newly available nesting sites.” Meanwhile, species with social foundresses reproduce near the place of origin and, therefore, do not extend their range as far.


Satellite nests are common among P. exclamans. A queen will fly somewhere between 0.15 and 11m away from the original nest to settle in a new location. About 16–39% of nests create satellites from May to July.
Similar to the wasp species Parischnogaster alternata, which constructs a multitude of nests in clusters in order to create protection through a dilution effect, the satellites are used as an insurance against attacks by predators and parasitoids. Of 12 nests that were knocked down by birds that had satellites, 66.7% of the colony survived by moving to the satellite, compared to the lower reproductive success of nests with no satellite that were attacked (5.7%). When Chalcoela iphitalis invades, the prevalence of satellites didn't increase the survivability, though it did have an effect when Elasmus polistis were introduced. It gave the P. exclamans a place to escape to.
Workers who are older typically start satellite nests and have more developed ovaries. Younger and lesser-developed workers join the satellite after its establishment. The distribution of workers between the main nest and satellite is very important because they are needed for the establishment of the satellite and for the continued running of the main nest, although after several months the main nest can become abandoned. If not enough workers follow the initial worker to the new nest, then it will most likely fail as a satellite.


Polistes exclamans live in social nests that are open combed. This leaves nests very susceptible to attacks by predators and by parasitoids. Attack by parasitoids will occur in the nest brood, as the invader will attempt to insert its own offspring into the host's nest. The two most common parasitoids are Chalcoela iphitalis and Elasmus polistis.


P. exclamans take several countermeasures against invasions. If the wasps detect an intruder they will violently bite and sting the location where the C. iphitalis moth has passed by. This will cause vibrations inside of the nest and the wasps inside will become alarmed and will move around jerkily. This phenomenon is known as the parasite dance. This will continue for up to 10 hours after the moth has been detected. If the moth is found it will be eaten immediately. However, this is not likely to happen. The moth lays its eggs in the nest, and when they hatch, they will take over the nest. As a result, many wasp pupae are aborted. This is commonly seen in the late summer when the moth is most abundant.
The second common parasitoid, Elasmus polistis, also has disastrous effects on the P. exclamans nest. Up to 80 E. polistis will hatch out of a single cell. The males emerge first, and then will exit the nest and wait until the females emerge. Once the females emerge, the males will mate and reproduce, quickly destroying the P. exclamans population. In some cases the invading E. polistis will hide larvae in the nest so that the P. exclamans cannot find them. This is important to the survival of P. exclamans. The hosts will attempt to remove as many parasitoids as possible to prevent them from spreading to nearby nests. This defense mechanism has not been proven to be effective, as more often than not the E. polistis larvae go undetected by the hosts. In one experiment conducted, it was found that over 60% of all nests lost brood to the parasitoids E. polistis or C. iphitalis in 1981. It was also observed that larger satellites have a greater risk of being parasitized. This is due to the fact that the large nests are typically older. This relationship between age and parasitism can be seen with the fact that older queens’ nests tend to be parasitized more than younger queens’ nests.


P. exclamans has several different predators. Their most dangerous predators are birds, which will fly by and knock the nest to the ground. This phenomenon was discovered by the disappearance of nests, and wasp nests being found on the ground near the bird's nest. It has also been found that birds eat the larvae from the P. exclamans nest. This attack kills the whole nest but it isn't very effective against the adults from the colony. When attacked, the adults fly away either to another colony or a satellite colony.
Attack by the ant Crematogaster laeviuscula is different from attacks by birds. Rather than knocking down the nest, the ants swarm all over the nest and remove the brood from it. The ants destroy the entire brood but they are unable to kill the adults.
Other predators attack the adults while they are foraging or traveling to satellite nests. It is difficult to determine the number of adults that are killed away from the nest because they are difficult to track. However, it has been observed that the queen's flight to the satellite nest isn't dangerous and does not reduce its survivability.
The idea of group living has been discussed by many evolutionists for its costs and benefits. Alexander predicted that the cost to large groups is that they are more likely to suffer from parasitism, but at the same time, they benefit by defense against predation. This theory is not supported in the case of P. exclamans because the parasitism does not always increase with nest size and the predation rate was independent of size.


Some animals may assess rivals through specific characteristics that are relevant to their fighting abilities; however, some animals, instead, use conventional characteristics to determine the competitive ability of their rivals. Conventional characteristics are signals that are indicative of the rival's abilities but are not a reflection of the animal's physiological or physical agonistic abilities. P. exclamans uses facial patterns as a conventional characteristic to determine the agonistic abilities of competitive rivals. Larger wasps have a greater amount of brown pigmented clypei. Wasps use these pigmented clypei to determine the viability of challenging a rival. The more pigmented the clypei or the larger the P. exclamans, the more likely the P. exclamans will be willing to challenge a rival. The less pigmented the clypei or the smaller the P. exclamans, the less willing it would be to challenge a rival. This assists in the minimization of the “costs of conflict during dominance competition among nest-founding queens.”


Polistes exclamans exhibit an alarm response, typical of many higher level eusocial Hymenoptera. Although it has been previously indicated that nest mates may alarm the rest of the nest through jerky movement and buzzing of wings, P. exclamans is capable of alarming the rest of the nest and attracting attacking wasps through chemical means by releasing a non-species-specific venomous alarm pheromone. Although a chemical signal to warn against attack would be evolutionarily adaptive, the P. exclamans only releases a response after the initial attack from and on the predator, as the venom is only released during the sting. This venom is capable of warning and coordinating a response from the nest and attracting nearby heterospecific or conspecific females from nearby colonies to attack the predator. This helps deter the predator from further attacking and is especially adaptive for the defense of the nest. Although certain other insects have been able to adapt the release of the pheromone to other means of communicating alarm, P. exclamans has yet to do so, indicating that it is still in its “primitive state in evolution of the complex systems of communication of alarm seen in higher social insects.” In one experiment, pheromones were extracted from female glands and sacs and were spread onto venom paper. It was then found that females were attracted upwind of the venom paper and some even attempted to sting it. This also had a heterospecific response where others also reacted to it. While it was found that one wasp couldn't release enough pheromones to elicit a response, if many individuals were alarmed they would elicit a response from the rest of the nest. However, this scent is not strong enough to reach other nests, and so neighboring nests must be alarmed by physical movements and wing flapping.


Polistes humilis, known as the common paper wasp, is a species of wasp in the Vespidae family that is found throughout Australia and which has been introduced to northern New Zealand. These paper wasps can be identified by their long thin legs and banded yellow and black coloring. They have been known to re-utilize old nests. While the species does not exhibit morphological class differences, there are distinct behavioral differences between queens and workers. In addition, the species is eusocial and benefits from relatedness between individuals. They are known for delivering a painful sting, especially when their nest is disturbed, a behavior that has been developed as a nest defense mechanism. While wasps are often viewed negatively, they play an important pollination role for many plants.


Polistes humilis is in the genus Polistes, which consists of 150 species that can be found in all regions except the world's coldest climates. Polistes humilis was the only species of the tribe Polistini found in New Zealand after it was accidentally introduced from Australia, prior to the introduction of the Asian paper wasp, Polistes chinensis in 1979. There are 11 different Polistes species found in Australia, and the Polistes humilis is the most prevalent one. Historically, Polistes variabilis has often been misidentified as a sub-species of Polistes humilis. But, recent photogenic analysis has indicated that these are two separate species. The species can be divided into two subspecies, P. humilis humilis which is found in northern Australia and P.humilis synoeus which can be found in the south.


This species of wasp can be identified by its slender body structure and banded coloring. Adults have yellow faces and are 10-15mm long with a tannish-red coloration. Males can be distinguished from females by a yellow marking on the abdomen area. In addition, Polistes humilis are generally bigger than most other paper wasps. Nests of this species can be identified by their cone shaped appearance with multiple hexagonal cells. The species builds its nest out of grey wood fiber material, which is a mixture of its own saliva and wood. Unlike most species of wasps, Polistes humilis colonies have been known to re-utilize old nests from year to year. Some colonies overwinter and shelter above the comb in colder months.


Polistes humilis is mostly found in Australia, particularly in southern Queensland, New South Wales, Victoria, and South Australia. While this species is native to Australia, the species was accidentally introduced to New Zealand in the 1880s and has  established a stable population in that country, largely confined to the North Island north of Tauranga and west of Te Kuiti. Environmentally, the highest abundance of P. humilis can be found in shrublands. However, the species can also be found in flax swamps and forest sites.


The colony cycle of Polistes humilis starts in the spring and can begin in three ways. Firstly, the colony cycle can begin with the founding of a new nest, typically by several foundresses. Secondly, the cycle can start with the re-utilization of an old nest, which can be several years old. Thirdly, the cycle can also begin with the continued use of an old nest as this species can overwinter. In situations where old nests are used, new eggs are typically laid around the old cells.
Throughout the year, production of Polistes humilis nests typically follow a distinctive cycle. In the spring, nests are founded by females that have overwintered and have been previously inseminated. After founding, worker females are produced in the late spring and early summer. Males and queen females are produced in the late summer and early fall.


In Polistes humilis nests, there is an observable hierarchy between reproducing queens and sterile workers. There are no outward physical differences between females; even small females have been known to produce eggs.  Since there are no morphological differences between females, behavioral characteristics are the primary determinate of whether a female reproduces or not.  These females can be determined by observation as they often receive solid food, honey, and water from worker females returning from foraging. Dominance is often displayed by a "tail wagging" behavior of the lower segment of the species. However, unlike most species that use behavioral characteristics to determine reproductive success, Polistes humilis does not exhibit high competition between females within the nest. This is likely due to the high degree of relatedness among nestmates.


Polistes humilis queens are singly mated, meaning that the eggs of the queen are fertilized by a single male and only one fertilization event occurs per female. However, within each colony, there are an average of two queens. This multiple queen behavior likely developed as a defense mechanism for the nest. Since different males can fertilize each female in the nest, genetic diversity is increased within the nest, which can help defend against disease. In addition, a distinctive characteristic of this species is that there is no inbreeding within P. humilis colonies. This suggests that dispersal is primarily male based and that males do not reproduce in their native colony. Dispersal of males likely happens before mating.


Polistes humilis are a haplodiploid species, with females developing from a fertilized egg and males developing from an unfertilized egg. In this system, queens are singly mated with full sisters sharing the paternal genetic information and either one of the maternal alleles. Therefore, sisters that share the same mother are 75% related in accordance with the haplodiploidy hypothesis. However, this ratio is skewed, making siblings less related, by having multiple queens in a nest. While this might benefit disease defense, skewing the relatedness ratio could disrupt the fragile eusocial behavior within the nest as some females within the nest are more related than others.


Since queen females have few morphological differences from worker females, they must use behavioral means to prevent them from laying eggs. As each queen selfishly wants to have as many offspring as possible, it is likely that oophagy occurs in Polistes humilis. This practice limits the eggs that weaker females can produce and reduces the genetic variability of the nest. Dominance of females can also be established through behavioral displays. Dominant females display their dominance by horizontal vibrations of the gaster and by mounting and wrestling with other females. These behaviors help the queens maximize their offspring's ability to survive and increases the genetic relatedness within the nest.


Polistes humilis are observed to subsist on food brought back to the nest by worker wasps. Once food is brought back to the nest, workers distribute the food to the queen and larvae. The species consumes primary water, pulp, carbohydrate and protein prey. In southern Australia, Polistes humilis appears to specialize in consuming lepidopteran larvae for protein as well as small spiders. Polistes humilis has to compete with other species for food, particularly the newly introduced, invasive species Vespula germanica. While Polistes humilis is very common now, competition for food could reduce its population in the future.


As a stinging wasp, Polistes humilis has a very powerful defense mechanism. The venom in the sting of the species helps with prey capture and nest defense from predators. The venom comes from the two tubular glands and is secreted by powerful muscles that coat the reservoir and squeeze out the venom. The venom is known to be used in fights between species and is often used in limited amounts. The venom is largely made of serotonin, histamine, tyramine, and dopamine which are all considered major pain producing components of the venom.


Polistes humilis also has developed two defenses against disease: genetic diversity and the production of cuticular antimicrobial compounds. There is a trade-off between these mechanisms, with larger colony sizes having more genetic diversity and smaller colonies having increased antimicrobials. This trade-off has likely developed by evolution as the cuticular compounds are metabolically expensive to produce so larger colonies may not be able to support this mechanism. In successful colonies, these mechanisms work together, as shown by the Pc80 locus. Genetic analysis shows that increased variation at this locus is positively correlated with antimicrobial strength. However, as the success of these mechanisms is very important for colony survival, these mechanisms are important limiting factors for maximum colony threshold size. Since antimicrobial compounds in Polistes humilis are found in the species' venom and only females produce the sting venom, larger colonies with more males might have lower effectiveness of this mechanism.  Group size and microbial defense are important characteristics to consider when determining disease susceptibility.


Polistes humilis is probably most known to humans by its painful sting. These stings often result from agitation of nest sites. Polistes humilis nests are often found in "modified habitats" where there is a mix of human structures and vegetation. Since nests are typically found in walls, eaves of buildings, and fences, humans are particularly at risk of accidentally disturbing a nest site. However, while the sting is very painful, humans are not at risk of serious injury from the sting unless they are allergic. The best way to avoid a sting is to simply stay away from known nest sites if possible, as these wasps typically only sting as a defense mechanism.


Polistes humilis are important to the overall ecosystem as pollinators. Since this species is one of the most populous species in Australia, it is responsible for the survival of many native wildlife. Polistes humilis appear to be widespread pollinators, not only in abundance but also in the species of plants pollinated. While this behavior is good for native plants, it has important implications for non-native species. The success of an introduced invasive species largely depends on the availability of pollinator relationships. Since Polistes humilis are general pollinators, they have been observed to contribute to the success of invasive species, such as the milkweeds Asclepias curassavica and Gomphocarpus fruticosus.


Polistes metricus (metric paper wasp or metricus paper wasp) is a wasp native to North America. In the United States, it ranges throughout the southern Midwest, the South, and as far northeast as New York, but has recently been spotted in southwest Ontario. A single female specimen has also been reported from Dryden, Maine. Polistes metricus is dark colored, with yellow tarsi and black tibia. Nests of Polistes metricus can be found attached to the sides of buildings, trees, and shrubbery.
Like other Polistes species, P. metricus, has evolved eusociality and demonstrates behaviors including nestmate discrimination and local mate competition. Like the other members of the order Hymenoptera, Polistes metricus has a haplodiploid genetic system. Nests of P. metricus have distinct characteristics like the ability to share nests with other Polistes species and reuse nests multiple seasons. Another distinction is that Polistes metricus foragers take off from their nests depending on how long their trip will be. For short flights, they exit the nest flying horizontally, while for long flights, they exit the nest flying straight up into a high altitude before pursuing their direction.
P. metricus prefers to use soft-bodied prey, especially caterpillars, to feed their larvae.