Taste plays a crucial role in the life of honey bees as their survival depends on the collection and intake of nectar and pollen, and other natural products. Here we studied the tarsal taste of honey bees through a series of behavioral and electrophysiological analyses. We characterized responsiveness to various sweet, salty and bitter tastants delivered to gustatory sensilla of the fore tarsi. Behavioral experiments showed that stimulation of opposite fore tarsi with sucrose and bitter substances or water yielded different outcomes depending on the stimulation sequence. When sucrose was applied first, thereby eliciting proboscis extension, no bitter substance could induce proboscis retraction, thus suggesting that the primacy of sucrose stimulation induced a central excitatory state. When bitter substances or water were applied first, sucrose stimulation could still elicit proboscis extension but to a lower level, thus suggesting central inhibition based on contradictory gustatory input on opposite tarsi. Electrophysiological experiments showed that receptor cells in the gustatory sensilla of the tarsomeres are highly sensitive to saline solutions at low concentrations. No evidence for receptors responding specifically to sucrose or to bitter substances was found in these sensilla. Receptor cells in the gustatory sensilla of the claws are highly sensitive to sucrose. Although bees do not possess dedicated bitter-taste receptors in the tarsi, indirect bitter detection is possible because bitter tastes inhibit sucrose receptor cells of the claws when mixed with sucrose solution. By combining behavioral and electrophysiological approaches, these results provide the first integrative study on tarsal taste detection in the honey bee.
Keywords: taste, gustation, gustatory receptors, insect, honey bee, tarsi, proboscis extension reflex, electrophysiology
Citation: de Brito Sanchez MG, Lorenzo E, Su S, Liu F, Zhan Y and Giurfa M (2014) The tarsal taste of honey bees: behavioral and electrophysiological analyses. Front. Behav. Neurosci. 8:25. doi: 10.3389/fnbeh.2014.00025
Received: 07 December 2013; Accepted: 16 January 2014;
Published online: 04 February 2014.
Edited by:Carmen Sandi, Ecole Polytechnique Federale De Lausanne, Switzerland
Reviewed by:Judith Reinhard, University of Queensland, Australia
Copyright © 2014 de Brito Sanchez, Lorenzo, Su, Liu, Zhan and Giurfa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Maria Gabriela de Brito Sanchez, Centre de Recherches sur la Cognition Animale, Building 4R3, Université de Toulouse, 31062 Toulouse Cedex 9, France e-mail: firstname.lastname@example.org