Department of Ecology and Evolution, University of Lausanne, Biophore, 1015 Lausanne, Switzerland.
Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, Jyväskylä FI-40014, Finland.
Evolution. 2019 Jun;73(6):1116-1132. doi: 10.1111/evo.13746. Epub 2019 May 3.
Models of sex-allocation conflict are central to evolutionary biology but have mostly assumed static decisions, where resource allocation strategies are constant over colony lifespan. Here, we develop a model to study how the evolution of dynamic resource allocation strategies is affected by the queen-worker conflict in annual eusocial insects. We demonstrate that the time of dispersal of sexuals affects the sex-allocation ratio through sexual selection on males. Furthermore, our model provides three predictions that depart from established results of classic static allocation models. First, we find that the queen wins the sex-allocation conflict, while the workers determine the maximum colony size and colony productivity. Second, male-biased sex allocation and protandry evolve if sexuals disperse directly after eclosion. Third, when workers are more related to new queens, then the proportional investment into queens is expected to be lower, which results from the interacting effect of sexual selection (selecting for protandry) and sex-allocation conflict (selecting for earlier switch to producing sexuals). Overall, we find that colony ontogeny crucially affects the outcome of sex-allocation conflict because of the evolution of distinct colony growth phases, which decouples how queens and workers affect allocation decisions and can result in asymmetric control.
性分配冲突模型是进化生物学的核心，但大多数模型都假设决策是静态的，即资源分配策略在蚁群的生命周期内保持不变。在这里，我们开发了一个模型来研究在一年生群居昆虫中，女王-工蚁冲突如何影响动态资源分配策略的进化。我们证明，有性个体的扩散时间通过对雄性的性选择影响性分配比。此外，我们的模型提供了三个与经典静态分配模型的既定结果不同的预测。首先，我们发现女王赢得了性分配冲突，而工蚁决定了蚁群的最大规模和生产力。其次，如果有性个体在刚孵化后直接扩散，那么雄性偏斜的性分配和早性成熟就会进化。第三，如果工蚁与新女王的亲缘关系更密切，那么对女王的比例投资预计会更低，这是性选择（选择早性成熟）和性分配冲突（选择更早地转为产生有性个体）相互作用的结果。总的来说，我们发现由于不同的蚁群生长阶段的进化，蚁群个体发生对性分配冲突的结果至关重要，因为这会分离出女王和工蚁如何影响分配决策，并可能导致不对称控制。
