Data from: Genetic structure of native ant supercolonies varies in space and time

Ant supercolonies are the largest cooperative units known in nature. They
consist of networks of interconnected nests with hundreds of reproductive
queens, where individuals move freely between nests, cooperate across nest
boundaries and show little aggression towards non-nestmates. The
combination of high queen numbers and free mixing of workers, queens and
brood between nests results in extremely low nestmate relatedness. In such
low-relatedness societies, cooperative worker behaviour appears
maladaptive because it may aid random individuals instead of relatives.
Here, we provide a comprehensive picture of genetic substructure in
supercolonies of the native wood ant Formica aquilonia using traditional
population genetic as well as network analysis methods. Specifically, we
test for spatial and temporal variation in genetic structure of different
classes of individuals within supercolonies and analyse the role of worker
movement in determining supercolony genetic networks. We find that
relatedness within supercolonies is low but positive when viewed on a
population level, which may be due to limited dispersal of individuals
and/or ecological factors such as nest site limitation and competition
against conspecifics. Genetic structure of supercolonies varied with both
sample class and sampling time point, which indicates that mobility of
individuals varies according to both caste and season and suggests that
generalizing has to be carried out with caution in studies of
supercolonial species. Overall, our analysis provides novel evidence that
native wood ant supercolonies exhibit fine-scale genetic substructure,
which may explain the maintenance of cooperation in these low-relatedness
societies.

蚂蚁超群体（supercolony）是自然界已知的最大规模合作单元。它们由相互连通的蚁巢网络构成，内含数百只生殖蚁后，个体可在蚁巢间自由移动、跨巢协作，且对非巢友几乎无攻击性。高数量蚁后与工蚁、蚁后及幼体（brood）在巢间自由混合的共同作用，导致同巢亲缘度极低。在这类低亲缘度社会中，工蚁的合作行为看似适应不良，因为其可能帮助的是随机个体而非亲属。本研究采用传统群体遗传学与网络分析方法，对本土林蚁（Formica aquilonia）超群体的遗传亚结构展开全面解析。具体而言，我们检验了超群体内不同品级个体的遗传结构在空间与时间上的变异，并分析了工蚁移动对塑造超群体遗传网络的作用。研究发现，从群体层面来看，超群体内部的亲缘度较低但仍为正值，这可能源于个体扩散受限以及巢址限制、与同种个体竞争等生态因素。超群体的遗传结构随样本品级与采样时间点发生变化，这表明个体的移动能力会随品级与季节发生改变，提示在研究超群体物种时需谨慎进行归纳概括。整体而言，本分析为本土林蚁超群体存在精细尺度的遗传亚结构提供了新证据，这或许能够解释这类低亲缘度社会中合作行为的维持机制。