Stopwatch for measuring the waggling duration: putative encoding mechanism of distance information in the honeybee
Hiroyuki Ai, Hiroyuki Ai , Ajayrama Kumaraswamy , Hidetoshi Ikeno , Thomas Wachtler
Department of Earth System Science, Fukuoka University, Fukuoka, Japan; Department of Earth System Science, Fukuoka University, 814-0180 Fukuoka, Japan ; Department of Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany ; School of Human Science and Environment, University of Hyogo, 670-009, Kakogawa, Japan ; Department of Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
The waggle dance represents a form of symbolic communication used by honeybees to convey the location of food sources via species-specific sound. Distance information is encoded in the duration of the waggle phase (von Frisch, 1967). Air-borne vibration is thought to be the most probable sensory cue delivered during waggle dance communication (Judd, 1995) where wing-beats produce local air-jet flows. During the waggle phase of the dance, the wingbeats of the dancer produce a train of vibration pulses that pass from the tail end of the dancer to a follower bee, which follows behind the dancer. The trains of vibration pulses are detected by the follower bees via Johnston’s organ located on the antennae. To uncover the neural mechanisms underlying the encoding of distance information in the waggle dance follower, we investigated morphology, physiology, and immunohistochemistry of 119 interneurons arborizing in the primary auditory center of the honeybee (Apis mellifera). We identified major interneuron types, DL-Int-1, DL-Int-2, and Bilateral DL-dSEG-LP, that responded with different spiking patterns to vibration pulses applied to the antennae. Experimental and computational analyses suggest that inhibitory circuits, acting as a kind of stopwatch, play a role in encoding and processing the duration of vibration pulse trains in the primary auditory center of the honeybee. Our results are critical for understanding how the honeybee deciphers information from the sound produced by the waggle dance and provide new insights regarding how common neural mechanisms are used by different species to achieve communication.