Prey specialization and chemical mimicry between Formica archboldi and Odontomachus ants

摘要

Formica ants are not known to be prey specialists on other ant species, however, for the past 60 years, field observations on Formica archboldi in the southeastern United States have noted that their nests are scattered with body parts of Odontomachus trap-jaw ants. This study investigates the relationship between F. archboldi and Odontomachus. Through a series of behavioral experiments and a descriptive study of their chemical ecology, I find: (1) behavioral evidence that F. archboldi are more capable predators of Odontomachus in comparison to other Formica. (2) F. archboldi match the cuticular hydrocarbon profiles of the native species of Odontomachus that they occur with. This includes O. brunneus and O. relictus and the intraspecific variation found across Florida populations of O. brunneus. (3) F. archboldi do not display a prey retrieval preference towards hydrocarbon-matching Odontomachus as compared to mismatching. (4) F. archboldi that match Odontomachus hydrocarbon profiles do not receive lower levels of aggression than mismatching F. archboldi. Beyond providing natural history insights into the relationship between these species, this study expands our knowledge of an important insect chemical phenotype. The intraspecific variability in F. archboldi cuticular hydrocarbon profiles is among the greatest reported for social insects and provides a unique case of how non-parasitic species can generate parasite-like chemical-mimic phenotypes.