title: Neuronal plasticity in the mushroom body calyx during adult maturation in the honeybee and possible pheromonal influences.
abstract: Honeybee workers express a pronounced age-dependent polyethism switching from various indoor duties to foraging outside the hive. This transition is accompanied by tremendous changes in the sensory environment that sensory systems and higher brain centers have to cope with. Foraging and age have earlier been shown to be associated with volume changes in the mushroom bodies (MBs). Using age- and task-controlled bees this study provides a detailed framework of neuronal maturation processes in the MB calyx during the course of natural behavioral maturation. We show that the MB calyx volume already increases during the first week of adult life. This process is mainly driven by broadening of the Kenyon cell dendritic branching pattern and then followed by pruning of projection neuron axonal boutons during the actual transition from indoor to outdoor duties. To further investigate the flexible regulation of division of labor and its neuronal correlates in a honeybee colony, we studied the modulation of the nurse-forager transition via a chemical communication system, the primer pheromone ethyl oleate (EO). EO is found at high concentrations on foragers in contrast to nurse bees and was shown to delay the onset of foraging. In this study, EO effects on colony behavior were not as robust as expected, and we found no direct correlation between EO treatment and synaptic maturation in the MB calyx. In general, we assume that the primer pheromone EO rather acts in concert with other factors influencing the onset of foraging with its effect being highly adaptive.
authors.affiliation: Department of Behavioral Physiology and Sociobiology, University of Würzburg, Biozentrum, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Muenz
authors.affiliation: Department of Behavioral Physiology and Sociobiology, University of Würzburg, Biozentrum, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Groh
authors.affiliation: INRA UR 406, Abeilles et Environnement, Site Agroparc, 84914, Avignon, France.
authors.forename: Alban
authors.initials: A
authors.lastname: Maisonnasse
authors.affiliation: INRA UR 406, Abeilles et Environnement, Site Agroparc, 84914, Avignon, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Le Conte
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6.
authors.forename: Erika
authors.initials: E
authors.lastname: Plettner
authors.affiliation: Department of Behavioral Physiology and Sociobiology, University of Würzburg, Biozentrum, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rössler
mesh_terms: D000818:Animals; D001516:Bees / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*; D015331:Cohort Studies; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D024521:Mushroom Bodies / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*; D056347:Neuroanatomical Tract-Tracing Techniques; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D009829:Oleic Acids / Q000378:metabolism*; D009929:Organ Size; D010675:Pheromones / Q000378:metabolism; D012919:Social Behavior
chemical_list: D009829:Oleic Acids; D010675:Pheromones; C033180:ethyl oleate
keywords: Apis mellifera; ethyl oleate; mushroom body; primer pheromone; synaptic plasticity