Division of labor and brain evolution in insect societies: Neurobiology of extreme specialization in the turtle ant Cephalotes varians
Division of labor and brain evolution in insect societies: Neurobiology of extreme specialization in the turtle ant Cephalotes varians
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DOI：
10.1371/journal.pone.0213618
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发表时间：
2019-03-27
期刊：
影响因子：
3.7
通讯作者：
Traniello, James F. A.
中科院分区：
文献类型：
--
作者：
Gordon, Darcy Greer;Zelaya, Alejandra;Traniello, James F. A.
强多型群居昆虫为研究分工的神经生物学基础提供了极好的模型。龟蚁，Cecutes varians，有不同的小工人，士兵，和生殖（雌/皇后）的形态与他们的行为配置文件：小身体的任务通才的未成年人缺乏士兵，这是专门阻止和守卫巢穴入口的phragmotic盾形头。Gynes发现了新的殖民地，在殖民地生长的早期阶段，他们的行为与士兵重叠。在这里，我们描述的模式，大脑结构和突触组织与分工的C。varians未成年工人，士兵，和gynes。我们量化了大脑体积，确定了大脑区域之间的比例关系，并量化了蘑菇体花萼中的微球和突触复合体的密度和大小，这些复合体对可能支持行为表现的高阶处理能力很重要。我们发现，女性的大脑体积明显更大;未成年工人和士兵的大脑大小相似。与他们更大的行为库相一致，未成年人的蘑菇体比士兵和妇科医生大得不成比例。士兵和女性有较大的视叶，这可能是重要的飞行和导航的女性，但服务于不同的功能在士兵。微肾小球较大，密度较小的工人，士兵和gynes没有什么不同。尽管士兵和女性行为存在差异，但大脑结构的对应关系可能反映了发育整合，这表明神经生物学指标不仅促进了我们对社会昆虫大脑进化的理解，而且可能有助于解决新种姓起源的问题。
Strongly polyphenic social insects provide excellent models to examine the neurobiological basis of division of labor. Turtle ants, Cephalotes varians, have distinct minor worker, soldier, and reproductive (gyne/queen) morphologies associated with their behavioral profiles: small-bodied task-generalist minors lack the phragmotic shield-shaped heads of soldiers, which are specialized to block and guard the nest entrance. Gynes found new colonies and during early stages of colony growth overlap behaviorally with soldiers. Here we describe patterns of brain structure and synaptic organization associated with division of labor in C. varians minor workers, soldiers, and gynes. We quantified brain volumes, determined scaling relationships among brain regions, and quantified the density and size of microglomeruli, synaptic complexes in the mushroom body calyxes important to higher-order processing abilities that may underpin behavioral performance. We found that brain volume was significantly larger in gynes; minor workers and soldiers had similar brain sizes. Consistent with their larger behavioral repertoire, minors had disproportionately larger mushroom bodies than soldiers and gynes. Soldiers and gynes had larger optic lobes, which may be important for flight and navigation in gynes, but serve different functions in soldiers. Microglomeruli were larger and less dense in minor workers; soldiers and gynes did not differ. Correspondence in brain structure despite differences in soldiers and gyne behavior may reflect developmental integration, suggesting that neurobiological metrics not only advance our understanding of brain evolution in social insects, but may also help resolve questions of the origin of novel castes.