Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing, China.
Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, USA.
Mol Ecol. 2019 Sep;28(18):4212-4227. doi: 10.1111/mec.15207. Epub 2019 Sep 26.
Reproductive investment is a central life history variable that influences all aspects of life. Hormones coordinate reproduction in multicellular organisms, but the mechanisms controlling the collective reproductive investment of social insects are largely unexplored. One important aspect of honey bee (Apis mellifera) reproductive investment consists of raising female-destined larvae into new queens by alloparental care of nurse bees in form of royal jelly provisioning. Artificial selection for commercial royal jelly production over 40 years has increased this reproductive investment by an order of magnitude. In a cross-fostering experiment, we establish that this shift in social phenotype is caused by nurse bees. We find no evidence for changes in larval signalling. Instead, the antennae of the nurse bees of the selected stock are more responsive to brood pheromones than control bees. Correspondingly, the selected royal jelly bee nurses are more attracted to brood pheromones than unselected control nurses. Comparative proteomics of the antennae from the selected and unselected stocks indicate putative molecular mechanisms, primarily changes in chemosensation and energy metabolism. We report expression differences of several candidate genes that correlate with the differences in reproductive investment. The functional relevance of these genes is supported by demonstrating that the corresponding proteins can competitively bind one previously described and one newly discovered brood pheromone. Thus, we suggest several chemosensory genes, most prominently OBP16 and CSP4, as candidate mechanisms controlling queen rearing, a key reproductive investment, in honey bees. These findings reveal novel aspects of pheromonal communication in honey bees and explain how sensory changes affect communication and lead to a drastic shift in colony-level resource allocation to sexual reproduction. Thus, pheromonal and hormonal communication may play similar roles for reproductive investment in superorganisms and multicellular organisms, respectively.
生殖投资是一个核心的生活史变量，影响着生命的各个方面。激素在多细胞生物中协调生殖，但控制社会性昆虫集体生殖投资的机制在很大程度上尚未被探索。蜜蜂（Apis mellifera）生殖投资的一个重要方面是通过工蜂用蜂王浆喂养来进行孤雌生殖，从而将雌性幼虫培育成新的蜂王。40 多年来，为了商业目的而对蜂王浆进行的人工选择，使这种生殖投资增加了一个数量级。在一项交叉寄养实验中，我们确定这种社会表型的转变是由工蜂引起的。我们没有发现幼虫信号发生变化的证据。相反，选择种群的工蜂触角对幼虫信息素的反应比对照蜂更敏感。相应地，选择的蜂王浆蜜蜂工蜂比未选择的对照工蜂对幼虫信息素更有吸引力。对选择和未选择种群的触角进行比较蛋白质组学分析表明了潜在的分子机制，主要是化学感觉和能量代谢的变化。我们报告了几个候选基因的表达差异，这些差异与生殖投资的差异相关。这些基因的功能相关性得到了支持，证明了相应的蛋白质可以竞争性地结合一种先前描述的和一种新发现的幼虫信息素。因此，我们提出了几个候选机制，包括嗅觉相关基因，尤其是 OBP16 和 CSP4，作为控制蜜蜂育王的候选机制，育王是一种关键的生殖投资。这些发现揭示了蜜蜂信息素交流的新方面，并解释了感觉变化如何影响交流，并导致群体水平资源分配到有性生殖的急剧转变。因此，信息素和激素通讯可能分别在超个体和多细胞生物的生殖投资中发挥类似的作用。
