title: Odorant cues linked to social immunity induce lateralized antenna stimulation in honey bees (Apis mellifera L.).
abstract: Hygienic behaviour (HB) is a social immunity trait in honey bees (Apis mellifera L.) whereby workers detect, uncap and remove unhealthy brood, improving disease resistance in the colony. This is clearly economically valuable; however, the molecular mechanism behind it is not well understood. The freeze-killed brood (FKB) assay is the conventional method of HB selection, so we compared odour profiles of FKB and live brood to find candidate HB-inducing odours. Surprisingly, we found that significantly more brood pheromone (β-ocimene) was released from FKB. β-ocimene abundance also positively correlated with HB, suggesting there could be a brood effect contributing to overall hygiene. Furthermore, we found that β-ocimene stimulated worker antennae in a dose-dependent manner, with the left antennae responding significantly stronger than right antennae in hygienic bees, but not in non-hygienic bees. Five other unidentifiable compounds were differentially emitted from FKB which could also be important for HB. We also compared odour profiles of Varroa-infested brood to healthy brood and found an overall interactive effect between developmental stage and infestation, but specific odours did not drive these differences. Overall, the data we present here is an important foundation on which to build our understanding the molecular mechanism behind this complex behaviour.
authors.affiliation: Department of Biochemistry &Molecular Biology and Michael Smith Laboratories, University of British Columbia, 2125 East Mall, Vancouver, British Colombia, V6T 1Z4, Canada.
authors.forename: Alison
authors.initials: A
authors.lastname: McAfee
authors.affiliation: Department of Biochemistry &Molecular Biology and Michael Smith Laboratories, University of British Columbia, 2125 East Mall, Vancouver, British Colombia, V6T 1Z4, Canada.
authors.forename: Troy F
authors.initials: TF
authors.lastname: Collins
authors.affiliation: Wine Research Center; Food, Nutrition and Health Building, University of British Columbia, 2205 East Mall, Vancouver, British Columbia, V6T 1Z4.
authors.forename: Lufiani L
authors.initials: LL
authors.lastname: Madilao
authors.affiliation: Department of Biochemistry &Molecular Biology and Michael Smith Laboratories, University of British Columbia, 2125 East Mall, Vancouver, British Colombia, V6T 1Z4, Canada.
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Foster
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000502:physiology*; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal; D003463:Cues; D060467:Disease Resistance; D008401:Gas Chromatography-Mass Spectrometry; D006920:Hygiene; D009812:Odorants; D057077:Varroidae