Tachykinin signaling inhibits task-specific behavioral responsiveness in honeybee workers
Bin Han, Qiaohong Wei, Fan Wu, Han Hu, Chuan Ma, Lifeng Meng, Xufeng Zhang, Mao Feng, Yu Fang, Olav Rueppell, Jianke Li
工蜂有高度精细的劳动分工，有的是哺育蜂，有的是采集蜂。这是由什么决定的呢？近日，中国农业科学院蜜蜂研究所科研人员从神经肽调节生理反应阈值的角度揭示了工蜂劳动分工的调控机制，为研究动物行为的可塑性提供了新的视角。相关研究成果发表于eLife。
论文作者韩宾介绍，蜜蜂是人工驯养的重要经济昆虫之一，已经有3000年以上的饲养历史。作为一种社会性昆虫，蜂群中的工蜂具有高度的劳动分工。年轻的工蜂主要从事幼虫哺育工作（哺育蜂），之后出巢从事食物采集工作（采集蜂）。采集蜂中又有更精细的采集花粉和采集花蜜的分工。然而，这种劳动分工的调控机制一直未被深入解析。
该研究利用蜜蜂喙伸反射发现，哺育蜂、花粉采集蜂、花蜜采集蜂对幼虫、花粉、蔗糖溶液都具有显著不同的反应阈值。这表明对特定刺激的反应阈值差异是决定工蜂劳动分工的关键。
进一步的神经肽组学研究发现，速激肽信号通路在调节反应阈值中发挥关键作用。随后，研究人员利用神经肽注射和RNA干扰证明，速激肽能够特异性地调控工蜂与其行为特异性相关的反应阈值，而对与任务无关的刺激没有影响。
研究同时发现，速激肽信号在调控中华蜜蜂与意大利蜜蜂采集和哺育行为差异中发挥重要作用。研究结果为深入理解蜜蜂社会行为的神经调控提供了新的理论依据。
来源：中国科学报 李晨
Abstract
Behavioral specialization is key to the success of social insects and leads to division of labor among colony members. Response thresholds to task-specific stimuli are thought to proximally regulate behavioral specialization, but their neurobiological regulation is complex and not well understood. Here, we show that response thresholds to task-relevant stimuli correspond to the specialization of three behavioral phenotypes of honeybee workers in the well-studied and important Apis mellifera and Apis cerana. Quantitative neuropeptidome comparisons suggest two tachykinin-related peptides (TRP2 and TRP3) as candidates for the modification of these response thresholds. Based on our characterization of their receptor binding and downstream signaling, we confirm a functional role of tachykinin signaling in regulating specific responsiveness of honeybee workers: TRP2 injection and RNAi-mediated downregulation cause consistent, opposite effects on responsiveness to task-specific stimuli of each behaviorally specialized phenotype but not to stimuli that are unrelated to their tasks. Thus, our study demonstrates that TRP signaling regulates the degree of task-specific responsiveness of specialized honeybee workers and may control the context specificity of behavior in animals more generally.
