Abstract
Honeybees are social insects, and individual bees take on different social roles as they mature, performing a multitude of tasks that involve multi-modal sensory integration. Several activities vital for foraging, like flight and waggle dance communication, involve sensing air vibrations through their antennae. We investigated changes in the identified vibration-sensitive interneuron DL-Int-1 in the honeybee Apis mellifera during maturation by comparing properties of neurons from newly emerged adult and forager honeybees. While comparison of morphological reconstructions of the neurons revealed no significant changes in gross dendritic features, consistent and region dependent changes were found in dendritic density. Comparison of electrophysiological properties showed an increase in the firing rate differences between stimulus and non-stimulus periods in foragers compared to newly emerged adult bees. The observed differences in neurons of foragers as compared to newly emerged adult honeybees suggest refined connectivity, improved signal propagation, and enhancement of response features possibly important for the network processing of air vibration signals relevant for the waggle-dance communication of honeybees.
Significance Statement In the darkness of the hive, honeybees inform each other about profitable food sources using stereotypic movements accompanied by specific sound patterns produced by wing-beats. Here we present a study of an identified vibration-sensitive neuron, named DL-Int-1, in the honeybee brain focusing on structural and functional adaptations by comparing data from young, newly emerged adult and mature forager honeybees. We found region-dependent changes in the morphological structure of DL-Int-1 as well as specific changes in its response properties, which suggest an adaptation process during maturation leading to a refinement in network connectivity and improved processing of waggle dance signals in the honeybee brain.
Footnotes
The authors report no conflict of interest.
This research was supported by Grant-in-Aids for Scientific Research from the Ministry of Education, Science, Technology, Sports, and Culture of Japan (Grant No. 22570079, 17K00414 and 18K160345); a grant for Challenging Exploratory Research (Grant 15K14569) from the Strategic International Cooperative Program, Japan Science and Technology Agency (JST); a grant from the German Federal Ministry of Education and Research (Grant 01GQ1116); and a grant from the Central Research Institute of Fukuoka University (Grant 151031). We thank Philipp Rautenberg for contributing to early stages of the project and Hiromu Tanimoto for constructive feedback.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
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