Gordon Deborah M
Department of Biology Stanford University Stanford California USA.
Ecol Evol. 2025 Sep 6;15(9):e72122. doi: 10.1002/ece3.72122. eCollection 2025 Sep.
The architecture of an ant colony's nest entrance modulates the regulation of activity in and out of the nest. This study considers how the architecture of nests of the desert harvester ant facilitates the regulation of foraging activity in an arid environment. Colonies must spend water, in water lost to evaporation when outside the nest, to obtain food and water. Previous work shows that encounters in the chamber just inside the entrance function as the valve to manage this tradeoff by regulating whether foragers decide to leave the nest on another trip. Here both complete and partial excavations, and observations inside active nests, were made in a long-term study population in New Mexico, US. Both the overall nest architecture and the set of chambers around the nest entrance are structured as a minimum spanning tree with the entrance chamber as hub. The entrance chamber is surrounded by 1-6 adjacent chambers not linked to each other, with 2-3 tunnels that lead to strings of widely spaced chambers descending 1-2 m. Observations with a videoscope inside active nests show that exterior workers of different tasks move up to the entrance chamber each day during foraging activity and descend below it afterwards, and that interior workers quickly carry food down from the entrance chamber to the deeper nest. Larger, older colonies have more nest entrances with tunnels leading to a single entrance chamber than younger, smaller colonies; this may reduce variability in encounter rates. The nest entrance architecture facilitates rapid adjustment of activity outside the nest. However, in current, deepening drought conditions, it is susceptible to damage when the upper clay layer of the calichi soil dries out, disrupting encounters in the entrance chamber and inhibiting the colony's capacity to manage water loss.
蚁群巢穴入口的结构调节着进出巢穴的活动规律。本研究探讨了沙漠收获蚁巢穴的结构如何在干旱环境中促进觅食活动的调节。蚁群在巢外时会因蒸发而失水，为获取食物和水必须消耗水分。先前的研究表明，入口内侧腔室中的相遇起到了阀门的作用，通过调节觅食者是否决定再次外出觅食来管理这种权衡。在美国新墨西哥州的一个长期研究种群中，进行了完整挖掘和部分挖掘以及对活跃巢穴内部的观察。整个巢穴结构以及巢穴入口周围的腔室集合都构建为以入口腔室为中心的最小生成树。入口腔室被1 - 6个彼此不相连的相邻腔室环绕，有2 - 3条隧道通向间距较大的一串腔室，这些腔室向下延伸1 - 2米。用内窥镜对活跃巢穴内部进行观察发现，不同任务的外部工蚁在觅食活动期间每天都会向上移动到入口腔室，之后再向下移动到其下方，而内部工蚁则迅速将食物从入口腔室向下搬运到更深的巢穴。较大、较老的蚁群比较小、较年轻的蚁群有更多通向单个入口腔室的巢穴入口；这可能会降低相遇率的变异性。巢穴入口结构有助于快速调整巢穴外的活动。然而，在当前干旱加剧的情况下，当钙积土的上层粘土层干涸时，它很容易受到破坏，扰乱入口腔室中的相遇情况，并抑制蚁群管理水分流失的能力。
