Stroeymeyt N, Joye P, Keller L
Department of Ecology and Evolution, Biophore, UNIL-Sorge, University of Lausanne, 1015 Lausanne, Switzerland
Department of Ecology and Evolution, Biophore, UNIL-Sorge, University of Lausanne, 1015 Lausanne, Switzerland.
Proc Biol Sci. 2017 Apr 26;284(1853). doi: 10.1098/rspb.2017.0269.
Collective foraging confers benefits in terms of reduced predation risk and access to social information, but it heightens local competition when resources are limited. In social insects, resource limitation has been suggested as a possible cause for the typical decrease in productivity observed with increasing colony size, a phenomenon known as Michener's paradox. Polydomy (distribution of a colony's brood and workers across multiple nests) is believed to help circumvent this paradox through its positive effect on foraging efficiency, but there is still little supporting evidence for this hypothesis. Here, we show experimentally that polydomy enhances the foraging performance of food-deprived ant colonies via several mechanisms. First, polydomy influences task allocation within colonies, resulting in faster retrieval of protein resources. Second, communication between sister nests reduces search times for far away resources. Third, colonies move queens, brood and workers across available nest sites in response to spatial heterogeneities in protein and carbohydrate resources. This suggests that polydomy represents a flexible mechanism for space occupancy, helping ant colonies adjust to the environment.
集体觅食在降低被捕食风险和获取社会信息方面具有益处，但在资源有限时会加剧局部竞争。在社会性昆虫中，资源限制被认为是随着蚁群规模增大而观察到的典型生产力下降的一个可能原因，这一现象被称为米切纳悖论。多巢型（蚁群的幼虫和工蚁分布在多个巢穴中）被认为通过其对觅食效率的积极影响有助于规避这一悖论，但这一假设仍缺乏有力的支持证据。在此，我们通过实验表明，多巢型通过多种机制提高了食物匮乏的蚁群的觅食表现。首先，多巢型影响蚁群内的任务分配，从而加快蛋白质资源的获取。其次，姐妹巢之间的通讯减少了对远处资源的搜索时间。第三，蚁群会根据蛋白质和碳水化合物资源的空间异质性，在可用巢穴地点之间移动蚁后、幼虫和工蚁。这表明多巢型代表了一种灵活的空间占据机制，有助于蚁群适应环境。
