Increasing attractiveness of baits with venom gland extract for Atta sexdens rubropilosa (Forel) (Hymenoptera: Formicidae).

The effect of larval cuticle extract (larval pheromone) and venom gland extract (trail pheromone) on transport of formulated baits by Atta sexdens rubropilosa (Forel) was studied in the field and under laboratory conditions. In the laboratory, we observed the transport to the nest of baits impregnated with 10 μL of venom gland extract (0.01 gland/bait) or 10 μL of larval cuticle extract (0.05 larva/bait). The most transported impregnated bait was then tested in the field placing rubber septa impregnated with 100 mL of extract or with 100 mL of solvent with the baits at 0.2, 1.0, 5.0, and 10.0 m away from the trail and from the nest entrance. Baits impregnated with venom gland extract were transported more often than baits formulated with larval cuticle extract. In field tests, the venom gland extract reduced the time required for ants to detect baits and increased the transport of baits displayed at 0.2 m from the foraging trail or nest entrance. The increase in the transport of impregnated baits and the lower time to be transported might help to reduce the loss of bait in the field and decrease the risk of active ingredient contacts with non-target species.