Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, CO 80523, USA.
Institute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Drive, Fairbanks, AK 99775, USA.
Integr Comp Biol. 2022 Oct 29;62(4):980-997. doi: 10.1093/icb/icac035.
Shifts in the timing of cyclic seasonal life-history events are among the most commonly reported responses to climate change, with differences in response rates among interacting species leading to phenological mismatches. Within a species, however, males and females can also exhibit differential sensitivity to environmental cues and may, therefore, differ in their responsiveness to climate change, potentially leading to phenological mismatches between the sexes. This occurs because males differ from females in when and how energy is allocated to reproduction, resulting in marked sex-differences in life-history timing across the annual cycle. In this review, we take a Tinbergian perspective and examine sex-differences in timing of vertebrates from adaptive, ontogenetic, mechanistic, and phylogenetic viewpoints with the goal of informing and motivating more integrative research on sexually dimorphic phenologies. We argue that sexual and natural selection lead to sex-differences in life-history timing and that understanding the ecological and evolutionary drivers of these differences is critical for connecting climate-driven phenological shifts to population resilience. Ontogeny may influence how and when sex-differences in life-history timing arise because the early-life environment can profoundly affect developmental trajectory, rates of reproductive maturation, and seasonal timing. The molecular mechanisms underlying these organismal traits are relevant to identifying the diversity and genetic basis of population- and species-level responses to climate change, and promisingly, the molecular basis of phenology is becoming increasingly well-understood. However, because most studies focus on a single sex, the causes of sex-differences in phenology critical to population resilience often remain unclear. New sequencing tools and analyses informed by phylogeny may help generate hypotheses about mechanism as well as insight into the general "evolvability" of sex-differences across phylogenetic scales, especially as trait and genome resources grow. We recommend that greater attention be placed on determining sex-differences in timing mechanisms and monitoring climate change responses in both sexes, and we discuss how new tools may provide key insights into sex-differences in phenology from all four Tinbergian domains.
周期性季节性生命史事件时间的转变是对气候变化最常见的响应之一，相互作用的物种之间的响应率差异导致物候期不匹配。然而，在一个物种内，雄性和雌性对环境线索也可能表现出不同的敏感性，因此，它们对气候变化的反应可能不同，这可能导致两性之间的物候期不匹配。这种情况发生是因为雄性与雌性在何时以及如何分配能量用于繁殖方面存在差异，导致整个年度周期内的生活史时间出现明显的性别差异。在这篇综述中，我们从适应、个体发生、机制和系统发育的角度，从丁伯根的角度来看待脊椎动物在时间上的性别差异，目的是为更具综合性的性别二态性物候学研究提供信息和动力。我们认为，性选择和自然选择导致了生活史时间的性别差异，理解这些差异的生态和进化驱动因素对于将气候驱动的物候期转变与种群恢复力联系起来至关重要。个体发生可能会影响生活史时间的性别差异出现的方式和时间，因为早期环境可以深刻影响发育轨迹、生殖成熟率和季节性时间。这些生物特征的分子机制与识别对气候变化的种群和物种水平的反应的多样性和遗传基础有关，有希望的是，物候学的分子基础越来越被理解。然而，由于大多数研究集中在单一性别上，对种群恢复力至关重要的物候期性别差异的原因通常仍不清楚。新的测序工具和基于系统发育的分析可能有助于提出关于机制的假设，以及洞察跨系统发育尺度的性别差异的一般“可进化性”，特别是随着性状和基因组资源的增加。我们建议更加关注确定时间机制的性别差异，并监测两性对气候变化的反应，我们还讨论了新工具如何从丁伯根的四个领域为物候期的性别差异提供关键见解。
