Tsuji Kazuki, Win Aye T
Department of Agro-Environmental Sciences, Faculty of Agriculture, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
Division of Rural Communities and Environmental Sciences, The United Graduate School of Agricultural Sciences, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-8580, Japan.
Biol Open. 2025 May 15;14(5). doi: 10.1242/bio.061976. Epub 2025 May 27.
Ant colonies have either a single nest (monodomy) or multiple nests (polydomy). A challenge is to explain their adaptive significance, specifying costs and benefits of each colony type. An explanation for ant polydomy is adaptation to spatially heterogeneous environments. With polydomy a colony can exchange complementary nutrition among nests within the entire colony occupying a wide territory. We tested this resource redistribution hypothesis using two closely related species, i.e. the polydomous ant Pheidole megacephala and the monodomous ant Pheidole noda. We put each colony in an artificially polydomous setting with two nests connected by tubes. We provided liquid food lacking protein to one nest and that lacking carbohydrates to the other nest. P. megacephala almost totally failed to produce brood when the connecting tubes were clipped, whereas it improved reproductive performance when the tubes were open. In marked contrast, P. noda managed to maintain high performance for a long period even when only nutritionally biased food was provided, most likely by relying on stored provisions that compensated for the missing nutrients. Based on these data, we propose the hypothesis that ant polydomy is an open economic strategy to counter heterogeneity in resource distribution 'spatially' by trading between nests and extending the resource searching area, whereas monodomy may be a closed economic strategy to cope with resource heterogeneity 'temporally' by withstanding food-depressed periods with stored nutrition and by efficient utilization of frugal diets. More empirical data in other ant taxa are necessary to test generality of this idea.
蚁群要么有一个单一蚁巢（单巢制），要么有多个蚁巢（多巢制）。一个挑战在于解释它们的适应性意义，明确每种蚁群类型的成本和收益。对蚂蚁多巢制的一种解释是对空间异质环境的适应。通过多巢制，一个蚁群能够在占据广阔领地的整个蚁群内的各个蚁巢之间交换互补性营养。我们使用两种亲缘关系密切的物种对这一资源重新分配假说进行了测试，即多巢制的大头蚁（Pheidole megacephala）和单巢制的诺氏大头蚁（Pheidole noda）。我们将每个蚁群置于一个人工多巢制环境中，有两个通过管子相连的蚁巢。我们给一个蚁巢提供缺乏蛋白质的液体食物，给另一个蚁巢提供缺乏碳水化合物的液体食物。当连接管被剪断时，大头蚁几乎完全无法繁殖后代，而当管子打开时，其繁殖性能得到改善。形成鲜明对比的是，即使只提供营养不均衡的食物，诺氏大头蚁也能长期保持良好的繁殖性能，很可能是依靠储存的食物来弥补缺失的营养。基于这些数据，我们提出这样一个假说：蚂蚁的多巢制是一种开放的经济策略，通过蚁巢之间的交换以及扩大资源搜索区域来应对资源分布在“空间上”的异质性，而单巢制可能是一种封闭的经济策略，通过利用储存的营养度过食物匮乏期并高效利用有限的食物来应对资源在“时间上”的异质性。需要其他蚂蚁类群的更多实证数据来检验这一观点的普遍性。
