School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
Ecosystem Change Ecology Team, Commonwealth Scientific and Industrial Research Organisation (CSIRO) Health and Biosecurity, Floreat, WA 6014, Australia.
Proc Natl Acad Sci U S A. 2023 Sep 12;120(37):e2217973120. doi: 10.1073/pnas.2217973120. Epub 2023 Aug 28.
In social animals, success can depend on the outcome of group battles. Theoretical models of warfare predict that group fighting ability is proportional to two key factors: the strength of each soldier in the group and group size. The relative importance of these factors is predicted to vary across environments [F. W. Lanchester, (1916)]. Here, we provide an empirical validation of the theoretical prediction that open environments should favor superior numbers, whereas complex environments should favor stronger soldiers [R. N. Franks, L. W. Partridge, , 197-199 (1993)]. We first demonstrate this pattern using simulated battles between relatively strong and weak soldiers in a computer-driven algorithm. We then validate this result in real animals using an ant model system: In battles in which the number of strong native meat ant workers is constant while the number of weak non-native invasive Argentine ant workers increases across treatments, fatalities of are lower in complex than in simple arenas. Our results provide controlled experimental evidence that investing in stronger soldiers is more effective in complex environments. This is a significant advance in the empirical study of nonhuman warfare and is important for understanding the competitive balance among native and non-native invasive ant species.
在社会性动物中，成功可能取决于群体战斗的结果。战争的理论模型预测，群体战斗能力与两个关键因素成正比：群体中每个士兵的力量和群体规模。这些因素的相对重要性预计会因环境而异[F. W. Lanchester，（1916）]。在这里，我们提供了对理论预测的实证验证，即开放环境应该有利于数量优势，而复杂环境应该有利于更强壮的士兵[R. N. Franks，L. W. Partridge，，197-199（1993）]。我们首先使用计算机驱动的算法在模拟战斗中展示了这种模式，然后使用蚂蚁模型系统在真实动物中验证了这一结果：在战斗中，当强壮的本地肉食蚂蚁工人的数量保持不变，而弱的非本地入侵阿根廷蚂蚁工人的数量在处理过程中增加时，在复杂的竞技场中比在简单的竞技场中死亡的更少。我们的结果提供了受控实验证据，表明投资于更强壮的士兵在复杂环境中更有效。这是对非人类战争的实证研究的重大进展，对于理解本地和非本地入侵蚂蚁物种之间的竞争平衡具有重要意义。
