Department of Ecology, Evolution, and Organismal Biology and Department of Entomology, Iowa State University, Ames, IA, 50010, USA.
Mol Ecol. 2017 Jun;26(11):2839-2841. doi: 10.1111/mec.14076.
In social species, there is a fundamental trade-off between 'me' and 'we'; that is, should I reproduce, or should I work to help others to reproduce? In this issue of Molecular Ecology, Okada et al. () delve into the evolution and genetic mechanisms of this core question, focusing on social caste formation in insects. The authors take advantage of a unique ant in the genus Diacamma, which has secondarily lost the classic, highly different queens and workers found in many other ants, bees and wasps. Instead, Diacamma ant castes are decided via aggressive dominance interactions among adult females, similar to dominance hierarchies seen in primitively social insects and many social vertebrates. But how does being dominated translate into reproductive shutdown and thus, the creation of a worker caste? The authors use transcriptomics to address this question, and discover that the key may lie in very rapid (within one day) changes in the regulation of nutrient signalling genes, and other genes related to nutrient storage and reproduction. In other words, being aggressed turns on or off genes that tell the ant's brain and physiology to go into 'sterile mode', whereas winning a fight stimulates other genes that ramp up reproductive traits. These results add weight to the idea that caste differences rely on a 'toolkit' of deeply conserved genes involved in core nutritional, reproductive and metabolic functions. In addition, these results emphasize the exquisite and rapid social environmental sensitivity of core toolkit genes during the production of distinct phenotypes.
在社会性物种中，存在着“我”和“我们”之间的基本权衡；也就是说，我应该繁殖，还是应该努力帮助他人繁殖？在本期《分子生态学》中，冈田等人深入探讨了这个核心问题的进化和遗传机制，重点研究了昆虫的社会等级形成。作者利用了一种独特的双叉蚁属蚂蚁，这种蚂蚁已经从许多其他蚂蚁、蜜蜂和黄蜂中具有经典的、高度不同的蚁后和工蚁中二次失去了这种特性。相反，双叉蚁的等级是通过成年雌蚁之间的攻击性优势相互作用决定的，类似于原始社会性昆虫和许多社会性脊椎动物中看到的优势等级。但是，被支配如何转化为生殖停止，从而产生工蚁等级呢？作者利用转录组学来解决这个问题，发现关键可能在于营养信号基因和其他与营养储存和生殖相关基因的快速（在一天内）调节变化。换句话说，被攻击会开启或关闭告诉蚂蚁大脑和生理进入“无菌模式”的基因，而赢得战斗则会刺激其他基因，从而增强生殖特征。这些结果进一步证实了这样一种观点，即等级差异依赖于参与核心营养、生殖和代谢功能的深度保守基因的“工具包”。此外，这些结果强调了在产生不同表型时，核心工具包基因对社会环境的敏感性。
