Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Minimal intraspecific aggression among tawny crazy ants (Hymenoptera: Formicidae) in Florida.

Abstract

Tawny crazy ants, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), are an invasive species found in states along the Gulf Coast of the USA. Their large populations are aggressive and can displace ant species already present in the area. Because tawny crazy ants are not territorial toward their own species within a locality, it was hypothesized that they may exhibit unicoloniality in their invasive range. To test this hypothesis, tawny crazy ants from separate locations in Florida were confined in small, enclosed arenas, and their interactions were observed and documented using a rating scale of aggression behaviors. Carbohydrate consumption also can affect aggression in ants, so starved and non-starved ants were tested separately. For non-starved ants, the level of aggression between worker ants increased if they were from different locations, but this interaction rarely escalated to fighting. When starved ants from different locations were given access to sucrose solution, the ants would exhibit trophallaxis rather than fighting over the food source. Queens from different colonies would quickly nest together. Thus, intraspecific aggression was not evident among tawny crazy ants collected from widely separated locations in Florida.