Starr S M, McIntyre N E
Department of Biological Sciences, Texas Tech University, Lubbock, TX.
Environ Entomol. 2020 Feb 17;49(1):230-237. doi: 10.1093/ee/nvz138.
Current climate projections for the Great Plains of North America indicate markedly increased air temperatures by the end of the current century. Because the Great Plains contains >80,000 intermittent wetlands that serve as irreplaceable wildlife habitat, this projected warming may have profound effects throughout a continental-scale trophic network. However, little research has been done to determine how projected warming may affect the growth, development, or survival of even common species in this region. We conducted laboratory warming experiments, using an abundant amphibious predatory insect, Enallagma civile (Hagen, 1861), as a model organism, to determine whether projected warming may affect development or survival. Eggs were collected and reared under four water temperature regimes representing current (26°C) and projected future conditions (32, 38, and 41°C). Nymph body size after each molt, development rate, and deaths were recorded. Elevated water temperatures were found to significantly affect the survivorship of E. civile eggs and nymphs as well as adult body size at emergence: an increase in temperature incurred a decrease in survival and size. Nymphs in the two hotter treatments were smaller and had low survivorship whereas individuals in the cooler temperatures generally survived to adulthood and were larger. Nymphs reared at 32°C experienced accelerated ontogenetic development compared with the other temperatures, going from egg to adult in 26 d. Projected elevated temperatures may, thus, be both advantageous and detrimental, causing concern for aquatic invertebrates in this region in the future.
当前对北美大平原的气候预测表明，到本世纪末气温将显著升高。由于大平原有超过80000个间歇性湿地，这些湿地是不可替代的野生动物栖息地，预计的这种变暖可能会对整个大陆规模的营养网络产生深远影响。然而，对于预计的变暖将如何影响该地区常见物种的生长、发育或生存，几乎没有开展相关研究。我们进行了实验室升温实验，以一种数量丰富的两栖捕食性昆虫——伊蚊（Enallagma civile，哈根，1861年）作为模式生物，来确定预计的变暖是否会影响其发育或生存。在代表当前（26°C）和预计未来条件（32、38和41°C）的四种水温条件下收集并饲养伊蚊卵。记录每次蜕皮后的若虫体型、发育速率和死亡情况。结果发现，水温升高会显著影响伊蚊卵和若虫的存活率以及羽化时成虫的体型：温度升高会导致存活率和体型下降。在两个较高温度处理下的若虫体型较小且存活率较低，而在较低温度下的个体通常能存活至成年且体型较大。与其他温度相比，在32°C饲养的若虫个体发育加速，从卵发育到成虫只需26天。因此，预计的温度升高可能既有利也有弊，这引发了对该地区未来水生无脊椎动物的担忧。
