Playbacks of Asian honey bee stop signals demonstrate referential inhibitory communication

Abstract

Referential communication provides a sophisticated way in which animals can communicate information about their environment. Previously, research demonstrated that honey bee stop signals encode predator danger in their fundamental frequency and danger context in their duration. Here, we show that these signals also encode danger in their vibrational amplitude. Stop signals elicited by the more dangerous predator, the large hornet (Vespa mandarinia) had significantly 1.5-fold higher vibrational amplitudes than those elicited by the small hornet predator (Vespa velutina). We measured the freezing vibrational response thresholds, and show that natural signals exceed these response thresholds. Finally, with artificial playbacks of the vibratory stop signal, we demonstrate that these signals referentially encode the danger that foragers experience at food source. Stop signals elicited by the larger and significantly more dangerous predator (V. mandarinia) were significantly 1.4-fold more inhibitory than stop signals elicited by the smaller and less dangerous predator (V. velutina).

Responsiveness to inhibitory signals changes as a function of colony size in honeybees ( Apis mellifera )

“…Although stop signallers typically deliver their signals directly to another bee, they can also deliver signals to the comb [12,26]. As with A. cerana stop signal playback experiments [26], we found that stop signals reliably elicited a stereotypical freezing response when delivered next to a bee. However, direct contact of the probe to the bee usually elicited an escape response.…”

“…The construction and testing of the artificial stop signal playback apparatus is published in [26]. Briefly, A. mellifera stop signals have a peak-to-peak vibrational displacement of 1.5 mm at 320 Hz [27].…”

Survival Sounds in Insects: Diversity, Function, and Evolution

“…A rather unique type of alarm signal is the "stop" signal of honeybees (Apidae). When Apis cerana bees encounter danger at a foraging site, they prevent further recruitment to the site by using vibratory signals to stop any waggle dance that would otherwise recruit bees to that site (Dong et al, 2019). Insects that use alarm signals to recruit help to the signaler include Umbonia sp.…”

Hornets and Honey Bees: A Coevolutionary Arms Race between Ancient Adaptations and New Invasive Threats

“…Such alterations in the flight pattern in response to the hornet presence has been documented for A. cerana, whose foragers increase their flying speed up to 20 times and fly in straight for the nest entrance covered by the carpet of shimmering bees [55]. The menace of a hornet attack can also reduce foraging activities in A. cerana colonies through the production of a vibrational "stop signal" emitted by workers, which inhibits waggle dancing and forager departure from the colony [7,73,74]. Once more, the intensity of the signal is tuned to the severity of the threat, since the larger and more dangerous V. mandarinia elicits a higher vibrational amplitude in the signal, which results in a more effective inhibition of foraging activities, with respect to the smaller V. velutina [7,73,74].…”