Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.
Proc Biol Sci. 2023 Jan 11;290(1990):20221942. doi: 10.1098/rspb.2022.1942. Epub 2023 Jan 4.
Caste-based reproductive division of labour in social insects is built on asymmetries in resource allocation within colonies. Kings and queens dominantly consume limited resources for reproduction, while non-reproductive castes such as workers and soldiers help reproductive castes. Studying the regulation of such asymmetries in resource allocation is crucial for understanding the maintenance of sociality in insects, although the molecular background is poorly understood. We focused on uric acid, which is reserved and used as a valuable nitrogen source in wood-eating termites. We found that king- and queen-specific degradation of uric acid contributes to reproduction in the subterranean termite . The urate oxidase gene (), which catalyses the first step of nitrogen recycling from stored uric acid, was highly expressed in mature kings and queens, and upregulated with differentiation into neotenic kings/queens. Suppression of uric acid degradation decreased the number of eggs laid per queen. Uric acid was shown to be provided by workers to reproductive castes. Our results suggest that the capacity to use nitrogen, which is essential for the protein synthesis required for reproduction, maintains colony cohesion expressed as the reproductive monopoly held by kings and queens.
社会昆虫中基于种姓的生殖劳动分工是建立在群体内部资源分配的不对称基础上的。蚁后和蚁王主要消耗有限的资源用于繁殖，而无生殖的工蚁和兵蚁等蚁种则帮助生殖蚁种。研究这种资源分配不对称的调节对于理解昆虫的社会性维持至关重要，尽管其分子背景还了解甚少。我们专注于尿酸，它在木食性白蚁中被储存并用作有价值的氮源。我们发现，尿酸的蚁后和蚁王特异性降解有助于地下白蚁的繁殖。尿酸氧化酶基因 () ，它催化从储存的尿酸中回收氮的第一步，在成熟的蚁后和即将分化为新雌蚁/新雄蚁中高度表达，并上调。尿酸降解的抑制减少了每只蚁后产卵的数量。尿酸被证明是由工蚁提供给生殖蚁种的。我们的结果表明，利用氮的能力对于繁殖所需的蛋白质合成至关重要，这种能力维持了以蚁后和蚁王的生殖垄断为表现形式的群体凝聚力。
