Nufio César R, Sheffer Monica M, Smith Julia M, Troutman Michael T, Bawa Simran J, Taylor Ebony D, Schoville Sean D, Williams Caroline M, Buckley Lauren B
Howard Hughes Medical Institute, Chevy Chase, Maryland, United Sates of America.
University of Colorado Natural History Museum, University of Colorado, Boulder, Colorado, United States of America.
PLoS Biol. 2025 Jan 30;23(1):e3002805. doi: 10.1371/journal.pbio.3002805. eCollection 2025 Jan.
Body size declines are a common response to warming via both plasticity and evolution, but variable size responses have been observed for terrestrial ectotherms. We investigate how temperature-dependent development and growth rates in ectothermic organisms induce variation in size responses. Leveraging long-term data for six montane grasshopper species spanning 1,768-3 901 m, we detect size shifts since ~1960 that depend on elevation and species' seasonal timing. Size shifts have been concentrated at low elevations, with the early emerging species (those that overwinter as juveniles) increasing in size, while later season species are becoming smaller. Interannual temperature variation accounts for the size shifts. The earliest season species may be able to take advantage of warmer conditions accelerating growth during early spring development, whereas warm temperatures may adversely impact later season species via mechanisms such as increased rates of energy use or thermal stress. Grasshoppers tend to capitalize on warm conditions by both getting bigger and reaching adulthood earlier. Our analysis further reinforces the need to move beyond expectations of universal responses to climate change to consider how environmental exposure and sensitivity vary across elevations and life histories.
体型缩小是生物通过可塑性和进化对气候变暖的常见反应，但陆地变温动物的体型反应存在差异。我们研究了变温生物中温度依赖的发育和生长速率如何导致体型反应的变化。利用六种生活在海拔1768 - 3901米山地的蝗虫物种的长期数据，我们发现自1960年左右以来的体型变化取决于海拔高度和物种的季节时间。体型变化主要集中在低海拔地区，早期出现的物种（以幼虫越冬的物种）体型增大，而后期出现的物种体型变小。年际温度变化导致了体型变化。最早出现的物种可能能够利用温暖的条件，在早春发育期间加速生长，而温暖的温度可能通过能量消耗率增加或热应激等机制对后期出现的物种产生不利影响。蝗虫倾向于通过增大体型和提前成年来利用温暖的条件。我们的分析进一步强调，需要超越对气候变化普遍反应的预期，考虑环境暴露和敏感性如何随海拔高度和生活史而变化。
