SUMMARY
Odor sensation is a sensory modality of considerable significance in the foraging behavior and interactional organization of ants. In the food bait technology, smell is the basis of attraction, which in turn, is the initial line of bait use and a key parameter for judging efficacy. Yet, baits that are currently available possess low attractiveness to many ant pests. Hence, strategies to produce ant bait with increased attractiveness are needed. Despite evidence that coffee has a diverse aroma complex that affects the behavior of honey bees, which share many social and genetic traits with ants, its attraction to formicine foragers have yet to be investigated. In a series of Y-tube olfactometer bioassays, we examined the behavioral responses of Tapinoma indicum (TI), Monomorium pharaonis (MP) and Solenopsis geminata (SG) to various coffee-induced odor stimuli, comprised of extracts from Arabica, Robusta and Liberica. All coffee species showed an influence on the behavior of TI, MP and SG workers, but the clearest effect was seen with Arabica. The workers of TI, MP and SG were more attracted to the odor of 0.01% Arabica extract (ONE), in comparison with 0.05% Arabica extract (TWO) or 0.05% Arabica extract (THREE). Arabica extract mixed with sugar (S) elicited significant attraction from workers of all three species when in balanced competition with either unsweetened Arabica extract or water. These results indicate that coffee, particularly Arabica is attractive to the foragers of TI, MP and SG, and can encourage the use of coffee in bait development. As coffee is already accepted in most human societies, the development of coffee-based bait may be an attractive option.
