The attraction of red imported fire ants (Solenopsis invicta) to soft baits that vary in nutritional content

Baits are the most important control tactic for red imported fire ants (Solenopsis invicta), but efficacy of baits can vary. For example, baits are typically more effective in spring and fall than in summer. Recent work has shown that this variation in bait efficacy is correlated with shifts in the nutritional requirements of fire ant colonies and associated food preferences of foraging fire ants workers. Baits for Solenopsis invicta could be tailored to better match the nutritional needs of fire ant colonies and the preferences of foraging fire ant workers. It is not practical, however, to manipulate the nutrient content of current bait matrices (e.g., corn grit). We have begun to develop “soft” bait matrices made from agar or gelatin in which the nutrient content can be easily manipulated. In this study, we quantified fire ant recruitment to agar and gelatin baits that varied in their sugar and amino acid content. Overall, significantly more fire ants recruited to agar baits than to gelatin baits. Among agar baits, those containing sugars were more attractive than agar baits containing water or a mixture of amino acids. This study suggests that agar baits containing sugars could be a possible alternative to currently used fire ant bait matrices.