Genotype and task influence stinging response thresholds of honeybee ( Apis mellifera L.) workers of African and European descent

Abstract

The stinging response thresholds of individual European and Africanized worker honeybees (Apis mellifera L.) were analyzed. Workers of each genotype performing defense (guard and soldier bees) and non-defense (nest and forager bees) associated tasks were collected and ex- posed to an electric stimulus of 0.5 mA, and the time they took to sting a leather substrate was recorded. Africanized bees had significant lower thresholds of response than European bees. Guards and soldiers were faster to sting than nest and forager bees for the Africanized geno- type, whereas for the European genotype, guards stung significantly faster than bees of the other three task groups. This is the first study that shows that individual bees specialized in two defensive tasks also have a lower response threshold for stinging. Our results fit a model of division of labor based on differences in re- sponse thresholds to stimuli among workers of different genotypes and task groups