title: Bees eavesdrop upon informative and persistent signal compounds in alarm pheromones.
abstract: Pollinators such as bees provide a critical ecosystem service that can be impaired by information about predation. We provide the first evidence for olfactory eavesdropping and avoidance of heterospecific alarm signals, alarm pheromones, at food sources in bees. We predicted that foragers could eavesdrop upon heterospecific alarm pheromones, and would detect and avoid conspicuous individual pheromone compounds, defined by abundance and their ability to persist. We show that Apis cerana foragers avoid the distinctive alarm pheromones of A. dorsata and A. mellifera, species that share the same floral resources and predators. We next examined responses to individual alarm pheromone compounds. Apis cerana foragers avoided isopentyl acetate (IPA), which is found in all three species and is the most abundant and volatile of the tested compounds. Interestingly, A. cerana also avoided an odor component, gamma-octanoic lactone (GOL), which is >150-fold less volatile than IPA. Chemical analyses confirmed that GOL is only present in A. dorsata, not in A. cerana. Electroantennogram (EAG) recordings revealed that A. cerana antennae are 10-fold more sensitive to GOL than to other tested compounds. Thus, the eavesdropping strategy is shaped by signal conspicuousness (abundance and commonality) and signal persistence (volatility).
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223 China.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223 China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wen
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223 China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Qu
authors.affiliation: Eastern Bee Research Institute, Yunnan Agricultural University, 650201 Kunming, China.
authors.forename: Shihao
authors.initials: S
authors.lastname: Dong
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223 China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223 China.|Eastern Bee Research Institute, Yunnan Agricultural University, 650201 Kunming, China.
authors.forename: Ken
authors.initials: K
authors.lastname: Tan
authors.affiliation: Division of Biological Sciences Section of Ecology, Behavior, and Evolution University of California, San Diego La Jolla, California, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Nieh
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000502:physiology; D001516:Bees / Q000187:drug effects / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects; D010675:Pheromones / Q000494:pharmacology*
chemical_list: D010675:Pheromones