Paternal-effects in a terrestrial ectotherm are temperature dependent but no evidence for adaptive effects

1. Global rising of average temperatures and increase in extreme climatic events may largely impact animal survival and reproduction. Yet, how variation in temperature may affect male fertility, in particular ejaculate traits, and whether this can in turn affect offspring fitness, is seldom addressed. Paternal effects may be of key importance as they could impact the rate and direction of evolutionary change in response to climate change. 2. We tested the effects of temperature experienced by males on sperm traits, and asked whether the paternal environmental temperature affected offspring phenotype. We further explored the potential for paternal effects to be adaptive, which would occur when offspring fitness increased under the same environmental conditions experienced by the fathers. We exposed male field crickets to high or low temperatures at two life stages, either throughout development or as adults, and tested sperm traits (number and quality) and offspring fitness (hatching suc...1. 全球平均气温上升与极端气候事件频发，或对动物的生存与繁殖造成显著影响。然而，温度波动如何影响雄性生育能力——尤其是精液性状（ejaculate traits），以及这一效应是否会进而影响后代适合度（offspring fitness），目前鲜有研究对此展开探讨。父本效应（paternal effects）的研究价值至关重要，因其或可影响物种应对气候变化时的进化速率与进化方向。 2. 本研究探究了雄性个体所经历的温度环境对精子性状（sperm traits）的影响，并验证了父本所处环境温度是否会对后代表型（offspring phenotype）产生作用。我们还进一步探索了父本效应的适应性潜力：当后代在与父本相同的环境条件下适合度提升时，该效应便具备适应性。我们将雄性田野蟋蟀在两个生命阶段（全程发育阶段或成年阶段）分别暴露于高温或低温环境中，并检测了其精子性状（数量与质量）以及后代适合度（孵化成功率……