Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan; Laboratory of Evolutionary Genomics, National Institute for Basic Biology, Okazaki, Japan.
Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
J Insect Physiol. 2021 May-Jun;131:104242. doi: 10.1016/j.jinsphys.2021.104242. Epub 2021 Apr 20.
Female insects can resorb their oocytes that could not be oviposited. Oocyte resorption is proposed to be an adaptive mechanism to optimize fitness in hostile environments, recouping resources that might otherwise be lost. Social insects have developed reproductive division of labor, wherein a small number of queens are devoted to egg production. Matured queens are highly specialized in reproduction and are largely dependent on nestmate workers for their nourishment. Therefore, oocyte resorption in the queens should be influenced by social factors such as the amount of available workforce, as well as external and abiotic factors. In this study, we investigated the seasonal dynamics and regulation factors of oocyte resorption in actively reproducing termite queens. We continuously collected the field-nests of the subterranean termite Reticulitermes speratus and demonstrated that queens frequently resorbed their oocytes in late summer, even though it is one of the most productive seasons in this species. On the other hand, our laboratory experiment showed that oocyte resorption itself was strongly induced regardless of the season. We also found that the rate of oocyte resorption was influenced by colony size (the number of attending workers). These results suggest that termite queens seasonally resorb their oocytes, yet oocyte resorption itself is regulated by social factors rather than by seasonal factors. Our study provides a unique insight into the regulation of reproduction in social insects.
雌性昆虫可以吸收未被排出的卵母细胞。卵母细胞的吸收被认为是一种适应机制，可以优化在恶劣环境中的适应性，回收可能丢失的资源。社会性昆虫已经发展出了生殖分工，其中少数女王专门从事产卵。成熟的女王在繁殖方面高度专业化，并且在很大程度上依赖于巢内工蚁来获取营养。因此，卵母细胞的吸收应该受到社会因素的影响，例如可用劳动力的数量，以及外部和非生物因素。在这项研究中，我们研究了积极繁殖的白蚁女王中卵母细胞吸收的季节性动态和调节因素。我们连续收集了地下白蚁 Reticulitermes speratus 的野外巢穴，并证明尽管这是该物种最具生产力的季节之一，但女王经常在夏末吸收其卵母细胞。另一方面，我们的实验室实验表明，无论季节如何，卵母细胞的吸收本身都被强烈诱导。我们还发现卵母细胞吸收的速度受到蚁群大小（工蚁的数量）的影响。这些结果表明，白蚁女王会季节性地吸收卵母细胞，但卵母细胞的吸收本身是由社会因素而不是季节因素调节的。我们的研究为社会性昆虫的繁殖调节提供了独特的见解。
