Corn leaf aphids are found wherever their host plants, cereals and grasses, grow. This mainly includes agricultural fields as well as grasslands. They are one of the most significant cereal pests in temperate and tropical regions, though their range is limited by their inability to survive in areas with harsh winter climates. (Parry, et al., 2012; Razmjou and Golizadeh, 2010)
Like all aphids, corn leaf aphids are oval-shaped, with soft bodies and a pair of cornicles protruding from the end of their abdomen. They are olive green to bluish-green in color, and have short antennae and dark legs. Both winged and wingless forms occur. Reportedly, their average body length is 2.56 mm. Nymphs resemble adults, only smaller. This species is polymorphic, due to their large worldwide range, as well as their many possible host plants. (Bhardwaj, 2012; Woehrmann and Hales, 1989; van Emden and Harrington, 2007)
Corn leaf aphids are hemimetabolous. Females give birth to live young via parthenogenesis. Offspring develop through 4 nymphal instars, each instar lasts about two days, and aphids then become adults. Time from birth to maturation can be as quick as 7 to 8 days. Development is faster in warmer temperatures. (Kuo, et al., 2006; Park and Obrycki, 2004; Razmjou and Golizadeh, 2010; Sharma and Bhatnagar, 2002)
Corn leaf aphids reproduce solely by parthenogenesis. Females produce genetically identical offspring without mating. Sexual forms of corn leaf aphids have only been found in a few populations that are host specific to Himalayan prune cherries (Prunus cornuta) in Pakistan. Males are produced occasionally in other colonies, but they do not mate. (van Emden and Harrington, 2007)
Corn leaf aphids produce live young by parthenogenesis. Females produce genetically-identical clones, without fertilization by males. Female fecundity changes with temperature, optimal temperatures occur around 20 to 25 degrees Celsius. A single female can produce anywhere from 5 to 75 offspring during her lifetime. Corn leaf aphids can reach maturity in about 7 to 8 days. Colony size and parthenogenesis typically peaks in July, or later in the host crop's growing season, depending on the region. (Kuo, et al., 2006; Park and Obrycki, 2004; Sharma and Bhatnagar, 2002; van Emden and Harrington, 2007)
Females give birth to live offspring, which likely takes a significant investment of energy. Since corn leaf aphids live in large colonies, their offspring immediately join the colony. Female parents may come in contact with their offspring, but there is likely no further parental care after birth. (van Emden and Harrington, 2007)
Like all aphid species, corn leaf aphids live in large colonies on their host plants. These colonies typically only include females and their genetically-identical offspring. Colonies can quickly grow to large sizes due to their short maturation time, as well as their ability to reproduce without mating. Both winged and non-winged forms are usually present. While some aphid species switch hosts throughout the season, the colony movement patterns of corn leaf aphids seems to vary by population and region. Many colonies overwinter in warmer, southern regions, and then migrate north in the spring once temperatures warm up. Researchers in India have reported night-time windborne migrations of corn leaf aphids, indicating at least some nighttime activity for this species. Another study in South Dakota focusing on wheat pests found that their colonies use both primary and secondary hosts. When wheat senesces, or is harvested in early August, aphids are unable to feed, so they move to a secondary host, typically cultivated grasses, for a period of several weeks. By September, winter wheat seedlings have developed, and corn leaf aphids move back to their wheat hosts. This pattern is likely not accurate for all areas of the world, and likely also varies depending on the host plant. (Hesler and Dagel, 2010; Kuo, et al., 2006; Reynolds and Wilson, 1989; van Emden and Harrington, 2007)
The exact home range of corn leaf aphids is unknown. Since much of their colony is wingless, their home range is likely restricted to their host plants and the surrounding areas. Some colonies move from primary to secondary host plants over the course of a season, while other colonies overwinter in warmer regions and move to colder regions once the temperature warms up. Additionally, winged aphids are generally not strong fliers, and typically do not fly long distances except on air currents. Their home range is likely different in different regions and populations. (Hesler and Dagel, 2010; Kuo, et al., 2006; van Emden and Harrington, 2007)
Aphids view their environment and other conspecifics visually, and show a preference for yellow surfaces. In the presence of a predator, aphids produce an alarm pheromone that alerts other aphids that danger is present, and typically elicits some sort of evasive behavior, such as walking away or dropping off of host plants. Aphids can also detect chemicals specific to their host plants. Since corn leaf aphids are not host specific to a single species, chemical detection may not be as significant in finding plants for feeding. Corn leaf aphids can detect when a plant is damaged, and will avoid feeding. When damaged, corn actually emits the same chemical as the aphid alarm pheromone, which keeps aphids away and prevents further damage to the plant. (Bernasconi, et al., 1998; van Emden and Harrington, 2007)
Like all aphids, corn leaf aphids are phloem feeders. They use their stylet mouthparts to pierce the plant vessels and suck out the sap. This species is polyphagous, and has many possible host plant species. They are a significant pest of cereals and grasses. Their most notable host is corn (Zea mays), which gives corn leaf aphids their common name. They also feed on sorghum (Sorghum bicolor), barley (Hordeum vulgare), oats (Avena), wheat (Triticum), and plants of the families Gramineae, Cyperaceae, and Typhaceae, as well as many other grasses and cereals. They feed on seedlings, leaves, and inside the whorl of these plants. Feedings often cause deformation of leaves and sterilization of inflorescences. (Razmjou and Golizadeh, 2010; van Emden and Harrington, 2007)
Both larvae and adult lady beetles are significant predators of corn leaf aphids, including Propylea japonica, Propylea quatuordecimpunctata, Anegleis cardoni, Cheilomenes sexmaculata, members of genus Hippodamia, and many members of genus Coccinella. Many other insect species are also predators of corn leaf aphids, including green lacewings, such as Chrysoperla nipponensis and larvae of Chrysoperla carnea, as well as several species of Syrphidae flies. Spiders are also predators, as well as some bird species. Corn leaf aphids have very few ways to defend against predators. Large colony numbers decrease individual predation threats. When attacked, aphids produce alarm pheromones to alert other individuals, who then exhibit escape behaviors. Additionally, feeding in the whorls of corn keeps them hidden and inaccessible to predators. Red imported fire ants tend colonies of corn leaf aphids and protect them from predators and parasitoids, in return for feeding on the honeydew they produce. (Bunker and Ameta, 2009; Greenstone and Shufran, 2003; Khuhro, et al., 2012; Omkar, et al., 2011; Papanikolaou, et al., 2013; Park and Obrycki, 2004; Tremblay, et al., 2001; Vinson and Scarborough, 1991; Yan, et al., 2012; van Emden and Harrington, 2007)
Corn leaf aphids are pests to cereals and grasses. They have many plant hosts, including corn, sorghum, barley, oats, and wheat, as well as plants of the families Gramineae, Cyperaceae, and Typhaceae. The feeding habits and honeydew production of a colony can lead to significant plant damage. Corn leaf aphids also transmit many important plant diseases. Like all aphids, corn leaf aphids have an obligate endosymbiotic bacterium, Buchnera aphidicola. This bacteria lives within them and produces essential amino acids that aphids do not get from their phloem diet. Red imported fire ants tend colonies in a mutualistic relationship. Ants eat the honeydew produced by corn leaf aphids, while protecting and tending the colony from other predators. Red imported fire ants have even been observed removing and destroying parasitized aphids from the colony. The parasitoid wasp Aphidius colemani uses corn leaf aphids as a host. The wasps lay an egg inside the aphid's body, and after the aphid dies, the wasp hatches. These wasps can be used as a form of pest control to decrease crop damage. Other parasitoid wasps that use corn leaf aphids as hosts includes Lysiphlebus testaceipes, Lysiphlebia japonica, Aphidius colemani, and Lipolexis oregmae, along with many other wasp species. Parasitic fungi of order Entomophthorales have been documented using corn leaf aphids as hosts. (Barta and Cagan, 2007; Dey and Akhtar, 2007; Rouhbakhsh, et al., 1996; Sampaio, et al., 2008; Vinson and Scarborough, 1991; van Emden and Harrington, 2007)
There are no known positive effects of corn leaf aphids on humans.
Corn leaf aphids are one of the most significant pests of cereals and grasses in temperate and tropical regions. They feed on many important crops such as corn, wheat, barley, and oats. In large numbers, these aphids cause damage through feeding, and can cover tassels with copious amounts of honeydew. They are also a significant vector of many plant diseases, including barley yellow dwarf virus (BYDV), sweet potato feathery mottle virus (SPFMV), millet red leaf virus (MRLV), sugarcane mosaic virus (SCMV), and maize dwarf mosaic virus (MDMV). There has been much research on the most effective control methods and insecticides, as well as the development of genetically resistant crops. (Jarasova, et al., 2013; Kuo, et al., 2006; Wosula, et al., 2013; van Emden and Harrington, 2007)
Corn leaf aphids have no special conservation status.
Angela Miner (author), Animal Diversity Web Staff, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
living in landscapes dominated by human agriculture.
reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
An animal that eats mainly plants or parts of plants.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
found in the oriental region of the world. In other words, India and southeast Asia.
development takes place in an unfertilized egg
chemicals released into air or water that are detected by and responded to by other animals of the same species
"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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