Cockroaches that exchange respiratory gases discontinuously survive food and water restriction

Metabolic rate and respiratory gas exchange patterns vary significantly both between and within species, even after a number of biotic and abiotic factors are taken into account. This suggests that such variation is of evolutionary importance, but the life history implications of this variation remain relatively poorly characterised. In the present study we examine the effect of metabolic variation on starvation and desiccation resistance in the speckled cockroach Nauphoeta cinerea. We also compare the starvation and desiccation resistance of individuals that exchange respiratory gases continuously with those that breathe discontinuously. We show that metabolic rate has no effect on survival during food and water restriction, but cockroaches exhibiting discontinuous gas exchange cycles (DGCs) live longer than those that do not and those provisioned with water lived longer than those that were not. This finding represents the first demonstration that DGCs confer a fitness benefit, and su...代谢速率与呼吸气体交换模式在物种间及物种内均存在显著差异，即便在控制了诸多生物与非生物因素后，该差异依然存在。这表明该类变异具有进化层面的重要性，但此类变异对物种生活史的影响仍相对缺乏系统性表征。本研究以斑光蠊（Nauphoeta cinerea）为实验对象，探究代谢变异对其饥饿抗性与脱水抗性的影响。同时比较了进行连续呼吸气体交换的个体与表现出不连续呼吸的个体在饥饿抗性与脱水抗性上的差异。本研究结果显示，代谢速率对食物与水分限制条件下的存活时长无显著影响，但表现出不连续气体交换循环（discontinuous gas exchange cycles，DGCs）的斑光蠊存活时长显著长于未表现出该循环的个体；且供水组个体的存活时长显著长于未供水组。本发现首次证明了不连续气体交换循环可带来适合度收益，且……