Temperature-dependent differences in male and female life history responses to a period of food limitation during development

With climate change, animals face both rising temperatures and more variable food availability. Many species have evolved an adaptative response to historic variation in food availability: they grow faster after a period of diet restriction (“compensatory growth”). However, higher temperatures may reduce the capacity for compensatory growth in ectotherms because individuals require more resources to support their increased metabolism. We experimentally tested how higher temperature affects compensatory growth by raising guppies (Poecilia reticulata) at a high or control temperature, and on a normal or temporarily restricted diet during early development. At the control temperature guppies on the restricted diet grew faster once their diet returned to normal. Both sexes showed compensatory growth. At the high temperature, both sexes also increased their growth rates after dietary restriction ended, but the life history outcomes differed. Males at the high temperature matured earlier and were smaller than males reared at the control temperature. In contrast, females at the high temperature matured later and were bigger than females at the control temperature. Our study highlights that rising temperatures could reduce the ability of fish to compensate for periods of low food availability, and that males and females can have different responses to the same environmental stressors.

随着气候变化，动物同时面临着气温升高与食物可获得性愈发不稳定的双重挑战。许多物种已演化出针对历史上食物可获得性波动的适应性响应：在经历一段时期的饮食限制后，它们会加速生长，这一现象被称为补偿性生长（compensatory growth）。然而，气温升高可能会削弱变温动物（ectotherms）的补偿性生长能力，因为个体需要更多资源来维持提升后的新陈代谢水平。本研究通过将孔雀鱼（Poecilia reticulata）分别置于高温与对照温度环境中，并在其早期发育阶段提供正常饮食或暂时性饮食限制，实验探究了气温升高对补偿性生长的影响。在对照温度环境下，接受饮食限制的孔雀鱼在恢复正常饮食后生长速度显著加快，且雌雄个体均表现出补偿性生长现象。在高温环境中，雌雄个体在饮食限制解除后同样提升了生长速率，但二者的生活史结局存在差异：相较于对照温度下饲养的雄性孔雀鱼，高温组雄性成熟更早且体型更小；与之形成鲜明对比的是，高温组雌性成熟更晚且体型大于对照温度下的雌性个体。本研究表明，气温升高可能会削弱鱼类应对短期食物匮乏的补偿能力，且雌雄个体对同一环境胁迫的响应模式存在显著差异。