Several ant species belonging to the Nylanderia genus have distinguished themselves as “tramp ants,” meaning that they have established an invasive habitat in a variety of ecoregions well outside of their native range. Many invasive ant pest species have become well established in the US, but not all of these invasive species are tramp ants. For example, the red-imported fire ant is native to the South American tropics, and their invasive presence in the southeast US proves that they can survive in a cooler region outside of their native range. However, they are not tramp ants because they are unable to survive in a variety of dissimilar habitats around the world. Many tramp ant species belonging to the Nylanderia genus are commonly referred to as “crazy ants.” The “Tawny,” or “rasberry crazy ant (N. fulva),” is probably the best known tramp ant in the US, especially in Texas where these ants invade residential homes in massive herds and establish infestations that are extremely difficult to eliminate. Unfortunately for Texas homeowners, another crazy ant species, N. bourbonica, has established an invasive habitat in Texas, as well as the Gulf Coast states.
bourbonica is commonly known as the “robust crazy ant,” and it’s the most widespread of all tramp ant species in the Nylanderia genus. This species is believed to have originated from southeast Asian or Australia, and records of their presence in southern Florida date back to 1924. Robust crazy ant workers that leave the nest to seek food sources are noticeably larger in size than Tawny crazy ant workers, but workers from both species are covered in hairs. Robust crazy ant workers are between two and three millimeters, dark brown to black, and have grey hairs on their head, midsection and abdomen. These ants usually nest in soil, but they are also known for nesting in piles of plant debris or beneath stacks of wood. Unlike their Tawny crazy ant relatives, robust crazy ants rarely invade homes in large numbers, and they generally prefer to feed on natural food sources like dead insects and honeydew. These ants are also more dependent on moisture than most other ant pest species, but they have been known to infest homes when the climate cools during the fall and winter, as well as during extreme weather events, such as heavy rainstorms and flash floods. If controlling these ants becomes necessary, baiting systems reportedly work well for eliminating robust crazy ants from homes.
Have you ever struggled to control a crazy ant infestation?