While foraging, animals can form inter- and intraspecific social signaling (i.e. one organism using signals to alert another about danger) networks to avoid similar predators. Honey bee sting alarm pheromones are multi-component blends，including isopentyl acetate (IPA) , octyl acetate (OA), benzyl acetate (BA), etc. However, the primary interspecific differences lie in the relative abundances of these different compounds.
Researchers from Chemical Ecology Group of Xishuangbanna Tropical Botanical Garden (XTBG) analyzed the volatile alarm pheromone produced by attacked workers of the most abundant native Asian honey bee, Apis cerana and tested the responses of other bee species to these alarm signals.
The researchers aimed to better understand the function of different honey bee alarm pheromone components in A. cerana, to determine if BA varies according to A. cerana task specialization, and to test if the sympatric species, A. dorsata and A. florea, can intercept and use this information.
They found that A. dorsata, A. florea, and A. cerana avoided BA on floral food and that A. cerana also avoided BA at its own nest. Therefore, the alarm information was honestly produced and mutualistically used by sympatric social bee species.
As compared to nest guards, A. cerana foragers produced higher levels of BA. In foragers, BA and (E)-dec-2-en-1-yl acetate (DA) generated the strongest antennal electrophysiological responses. BA was also the only compound that alerted flying foragers and inhibited A. cerana foraging. BA thereby decreased A. cerana foraging for risky sites.
Interestingly, although BA occurs only in trace amounts and is nearly absent in sympatric honeybee species, these floral generalists detected and avoided BA as strongly as they did to their own alarm pheromone on natural inflorescences.
The results showed that at foragers of different native Asian honey bee species can detect and use benzyl acetate (BA) to avoid danger.