Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6.
Cornell Lab of Ornithology, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA.
Proc Biol Sci. 2023 Mar 8;290(1994):20221894. doi: 10.1098/rspb.2022.1894. Epub 2023 Mar 1.
Sociality can provide many benefits, including increased foraging success, reproductive opportunities and defence against predation. How does sociality influence the dominance hierarchies of ecological competitors? Here, we address this question using a large citizen science dataset of competitive interactions among birds foraging at backyard feeders, representing a network of over 55 000 interactions among 68 common species. We first show that species differ in average group size (the number of conspecifics observed together) as a fundamental measure of sociality. When analysing heterospecific competition, we find that sociality is inversely related to dominance. On average, a single individual from a solitary species is more likely to displace a size-matched opponent than a single individual from a social species. Yet, we find that social species gain an increase in their competitive advantage when in the presence of their conspecifics, which may occur as a result of dynamics within their groups. Finally, we show that more social species have relatively fewer dominance interactions with heterospecifics, and more with conspecifics. Overall, these results demonstrate that sociality can influence competition in ecological networks. More social species have decreased competitive ability as individuals, but they may gain competitive ability in groups.
社会性可以带来许多好处，包括增加觅食的成功率、繁殖机会和防御捕食。社会性如何影响生态竞争者的支配等级？在这里，我们使用后院喂食器中鸟类觅食的大量公民科学数据集来解决这个问题，该数据集代表了 68 个常见物种之间超过 55000 次相互作用的网络。我们首先表明，物种在平均群体大小（观察到的同种个体数量）上存在差异，这是衡量社会性的一个基本指标。在分析异质种竞争时，我们发现社会性与支配力呈负相关。平均而言，来自独居物种的单个个体比来自社会性物种的单个个体更有可能取代体型匹配的对手。然而，我们发现，当社会性物种的同类存在时，它们的竞争优势会增加，这可能是由于它们群体内部的动态变化造成的。最后，我们表明，更多的社会性物种与异质种的支配性相互作用相对较少，而与同种的相互作用相对较多。总的来说，这些结果表明，社会性可以影响生态网络中的竞争。社会性更强的物种作为个体的竞争能力下降，但它们在群体中可能获得竞争能力。
