Smoke conditions affect the release of the venom droplet accompanying sting extension in honey bees (Hymenoptera: Apidae)

Authors: Gage, Stephanie; AHUMADA, FABIANA - Betatec Hop Products Inc; Rivera, Angela; Graham, Richard; DeGrandi-Hoffman, Gloria

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2018
Publication Date: 8/14/2018
Citation: Gage, S.L., Ahumada, F., Rivera, A.M., Graham, R.H., Hoffman, G.D. 2018. Smoke conditions affect the release of the venom droplet accompanying sting extension in honey bees (Hymenoptera: Apidae). Journal of Insect Science. 18(4):1-7. https://doi.org/10.1093/jisesa/iey073.
DOI: https://doi.org/10.1093/jisesa/iey073

Interpretive Summary: The defensive response of honey bees is one of the most well-known and feared honey bee behaviors. With sufficient agitation, honey bees will mobilize and sting the intruder, who is likely to incur additional stings. To inspect and manage colonies, beekeepers apply smoke to decrease the likelihood of being stung. The use of smoke is a ubiquitous beekeeping practice, but the reasons behind why smoke is effective remains unknown. In this study, we sought to examine how smoke affects honey bee defensive behavior by examining individual bees. We applied a brief voltage to a bee, ranging from mild to strong, and examined components of the honey bee sting behavior under two smoke types: hops and burlap. We found that the venom droplet, which sometimes appears on the stinger, is more likely to be present at higher levels of agitation. Under smoke conditions, bees are less likely to have a venom droplet appear on their stinger. Based on these results, we propose that venom droplet release corresponds with greater agitation in individual bees, and that smoke reduces the probability of its release. These results help us to better understand the defensive response of honey bees.

Technical Abstract: Honey bees (Apis mellifera L.) are social insects that have evolved a coordinated defensive response to ensure colony survival. Their nests may contain valuable resources such as pollen and nectar that are attractive to a range of insect and mammalian intruders and need protecting. With sufficient provocation, honey bees will mobilize and sting intruders, who are likely to incur additional stings. To inspect and manage their colonies, beekeepers apply smoke to decrease the likelihood of being stung. The use of smoke is a ubiquitous beekeeping practice, but the reasons behind its efficacy remains unknown. In this study, we examined the effects of smoke on honey bee defensive behavior by assessing individual sting extension responses under smoke conditions. We applied a brief voltage to the bee, ranging from a mild to a strong perturbation, and assessed four components of the sting extension reflex using two types of smoke. We found that smoke did not influence the probability of sting extension, but it did affect whether a venom droplet was released with the stinger. The venom droplet was more likely to be released at higher voltage levels, but this effect was significantly reduced under smoke conditions. Based on these results, we propose that the venom droplet coincides with greater agitation in individual bees; and smoke reduces the probability of its release.