Date Published: February 8, 2017
Publisher: Public Library of Science
Author(s): Michael Ramsey, Martin Bencsik, Michael I. Newton, Wulfila Gronenberg.
It is known that honeybees use vibrational communication pathways to transfer information. One honeybee signal that has been previously investigated is the short vibrational pulse named the ‘stop signal’, because its inhibitory effect is generally the most accepted interpretation. The present study demonstrates long term (over 9 months) automated in-situ non-invasive monitoring of a honeybee vibrational pulse with the same characteristics of what has previously been described as a stop signal using ultra-sensitive accelerometers embedded in the honeycomb located at the heart of honeybee colonies. We show that the signal is very common and highly repeatable, occurring mainly at night with a distinct decrease in instances towards midday, and that it can be elicited en masse from bees following the gentle shaking or knocking of their hive with distinct evidence of habituation. The results of our study suggest that this vibrational pulse is generated under many different circumstances, thereby unifying previous publication’s conflicting definitions, and we demonstrate that this pulse can be generated in response to a surprise stimulus. This work suggests that, using an artificial stimulus and monitoring the changes in the features of this signal could provide a sensitive tool to assess colony status.
Honeybee (Apis mellifera) colonies kept for commercial purposes are usually housed in beehives, with population sizes exceeding 40,000 individuals depending on the season. During the spring/summer active season there is a higher volume of workers assigned to gathering resources, such as pollen and nectar, to sustain them over the inactive winter months when the population size reduces . Colonies are comprised of a single queen, a few hundred male drones and thousands of female worker bees, as well as developing eggs, larvae and pupae within the honeycomb [1,2].
No ethical approval was required as this study wholly focussed on the in-situ, non-invasive, acquisition of data from invertebrate colonies.
Analysis of the whooping signal dataset recorded in France is presented below. For comparison, the analysis of the UK dataset is supplied in S3–S8 Figs of the Supplementary Material.