Muenz Thomas S, Groh Claudia, Maisonnasse Alban, Le Conte Yves, Plettner Erika, Rössler Wolfgang
Department of Behavioral Physiology and Sociobiology, University of Würzburg, Biozentrum, Am Hubland, 97074, Würzburg, Germany.
INRA UR 406, Abeilles et Environnement, Site Agroparc, 84914, Avignon, France.
Dev Neurobiol. 2015 Dec;75(12):1368-84. doi: 10.1002/dneu.22290. Epub 2015 Jun 1.
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.
蜜蜂工蜂表现出明显的年龄依赖性多型行为，从各种室内职责转变为在蜂巢外觅食。这种转变伴随着感觉环境的巨大变化，感觉系统和高级脑中枢必须应对这些变化。此前研究表明，觅食行为和年龄与蘑菇体（MBs）的体积变化有关。本研究使用年龄和任务受控的蜜蜂，提供了自然行为成熟过程中MB花萼神经元成熟过程的详细框架。我们发现，MB花萼体积在成年后的第一周就已经开始增加。这一过程主要由肯扬细胞树突分支模式的扩展驱动，随后在从室内职责实际转变为室外职责的过程中，投射神经元轴突终扣会发生修剪。为了进一步研究蜜蜂群体中分工的灵活调节及其神经元相关性，我们通过化学通讯系统——引物信息素油酸乙酯（EO），研究了哺育蜂向觅食蜂转变的调节过程。与哺育蜂相比，在觅食蜂身上发现高浓度的EO，并且已证明它会延迟觅食行为的开始。在本研究中，EO对群体行为的影响不如预期强烈，并且我们没有发现EO处理与MB花萼突触成熟之间存在直接相关性。一般来说，我们认为引物信息素EO与其说是单独起作用，不如说是与其他影响觅食行为开始的因素协同作用，其效果具有高度适应性。
