Flight and fight: a comparative view of the neurophysiology and genetics of honey bee defensive behavior

Abstract

Honey bee nest defense involves guard bees that specialize in olfaction-based nestmate recognition and alarm-pheromone-mediated recruitment of nestmates to sting. Stinging is influenced by visual, tactile and olfactory stimuli. Both quantitative trait locus (QTL) mapping and behavioral studies point to guarding behavior as a key factor in colony stinging response. Results of reciprocal F1 crosses show that paternally inherited genes have a greater influence on colony stinging response than maternally inherited genes. The most active alarm pheromone component, isoamyl acetate (IAA) causes increased respiration and may induce stress analgesia in bees. IAA primes worker bees for 'fight or flight', possibly through actions of neuropeptides and/or biogenic amines. Studies of aggression in other species lead to an expectation that octopamine or 5-HT might play a role in honey bee defensive response. Genome sequence and QTL mapping identified 128 candidate genes for three regions known to influence defensive behavior. Comparative bioinformatics suggest possible roles of genes involved in neurogenesis and central nervous system (CNS) activity, and genes involved in sensory tuning through G-protein coupled receptors (GPCRs), such as an arrestin (AmArr4) and the metabotropic GABA(B) receptor (GABA-B-R1).

Fig. 1

A conceptual model of honey bee defensive behavior. Guard bee specialization is influenced by genetic effects and social interactions. Guards release alarm pheromone when they become alerted, resulting in release of neurohormones (neuropeptides or biogenic amines) that influences the ‘fight or flight’ response analogous to that of vertebrates, which includes increased metabolic rate and stress-induced analgesia. The result is a release of flight activity, searching for visual targets, and stinging behavior. Both additive and paternal genetic effects on whole-colony stinging behavior have been demonstrated, suggesting that imprinted gene expression affects defensive behavior.