Acromyrmex leaf-cutter ants as pests: aggression and cuticular hydrocarbons
Patricia J. Folgarait, Patricia J. Folgarait
Ants Laboratory, Dept Science & Technology, National University of Quilmes, Buenos Aires, Argentina; Ants Laboratory, Dept Science & Technology, National University of Quilmes, Buenos Aires, Argentina
Ants are known for defending their colony territories against conspecific and heterospecific workers. To maintain their territories, they exhibit different levels of aggression based on their nestmate recognition abilities. The main recognition cues involve cuticular hydrocarbons; depending on the dissimilarity of the chemical profile of their opponent to their own, and on the template they have, ants fight or not. Here, I studied Acromyrmex leaf-cutter ants that have attained pest status and seemed not to be aggressive towards non-nestmates. I performed aggression tests using field colonies from forestry plantations from Argentina, evaluated their geographical distance, and performed chemical analyses of their cuticular hydrocarbons. Focus was placed on A. crassispinus but data on 3 other species (A. heyeri, A. ambiguus, and A. lundii) were also gathered. The great majority of the aggression tests among ants from different field colonies of the same species exhibited no fights. No relationship between aggression and geographical distance or chemical distance was found either. Chemical profiles of the different species vary in their complexity and included linear and branched alkanes ranging from C25 to C37. Interspecific aggression was observed in the majority of the tests ran using laboratory colonies. Aggression results are discussed in relation to the species simplicity/complexity of their chemical profiles, as well as to their field density and habitat characteristics.