Data from: How maternal investment varies with environmental factors and the age and physiological state of wild tsetse Glossina pallidipes and Glossina morsitans morsitans

Theory suggests females should optimize resource allocation across reproductive bouts to maximize lifetime reproduction, balancing current and future reproductive efforts according to physiological state and projected survival and reproduction. Tests of these ideas focus on long-lived vertebrates: few measure age-related reproductive output in iteroparous invertebrates, or partition reserves between those allocated to offspring versus mothers. We investigated how maternal age, and environmental and physiological factors influence reproductive investment in wild tsetse, Glossina pallidipes Austen and G. morsitans morsitans Westwood. Tsetse provide a tractable system to measure reproductive allocation. Females exhibit high maternal investment, producing single, large offspring that rely exclusively on maternal reserves. We find that mothers in better physiological condition and experiencing cooler temperatures produce larger offspring. Pupal size increases significantly but weakly with age. In both species, females with less fat invest proportionately more in offspring. Post-partum fat decreases in flies with badly frayed wings: poor flight capability may limit their feeding efficiency, or they may sacrifice more reserves as a terminal investment. Our results support evidence that offspring size increases with maternal size, investment depends on the environment, and females with lower chances of future reproduction invest more into current offspring. We discuss the implications of maternal effects for predicting vector population responses to environmental change.理论研究表明，雌性个体需优化各繁殖周期的资源分配策略，以实现终身繁殖成效的最大化；同时需结合自身生理状态、预期存活寿命与繁殖潜力，权衡当前与未来的繁殖投入。现有针对该理论的实证检验多聚焦于长寿命脊椎动物，目前鲜有研究对多次繁殖的（iteroparous）无脊椎动物的年龄相关繁殖产出（age-related reproductive output）开展测定，也极少探讨其将储存资源在后代与母体间的分配权衡。本研究以野生舌蝇（*Glossina pallidipes* Austen 与 *G. morsitans morsitans* Westwood）为研究对象，探究了母体年龄、环境与生理因素对其繁殖投入的影响。舌蝇是研究繁殖分配（reproductive allocation）的理想模式系统：雌性母体的繁殖投入极高，每次仅繁育1只大型后代，且后代的生长完全依赖母体储存的营养储备。研究结果显示，生理状态更佳且处于较低温度环境中的母体，其后代体型更大；蛹的体型随母体年龄增长呈显著但微弱的上升趋势。在两个舌蝇物种中，脂肪储备较少的雌性会将更高比例的资源分配给后代。翅膀严重磨损的雌性个体产后脂肪储备显著下降：这可能是由于飞行能力受损限制了其取食效率，或是它们将更多储备作为终端投资（terminal investment）投入当前繁殖。本研究结果印证了已有研究结论：后代体型随母体体型增大而增加，繁殖投入受环境条件调控，且未来繁殖机会较低的雌性会为当前后代投入更多资源。最后，我们探讨了母体效应（maternal effects）在预测媒介种群对环境变化的响应方面的研究意义。