Department of Biological Sciences, University of Toronto Scarborough, Scarborough, ON M1C 1A4, Canada.
Department of Biology, University of Western Ontario, 1151 Richmond St. N, London, ON N6A 5B7, Canada.
Integr Comp Biol. 2022 Aug 25;62(2):179-190. doi: 10.1093/icb/icac073.
Temperature challenges are one of the leading abiotic causes of success or failure of non-native species in a novel environment, and this is particularly true for low temperatures. Establishing and reproducing in a novel thermal environment can alter survival, behavior, and traits related to fitness. It has been proposed that plasticity or adaptation of thermal tolerance may allow an introduced species to thrive, or that successful invaders may be those with a thermal breadth in their native habitat that encompasses their new environment. Here, we tested these hypotheses using native and invasive populations of Australian redback spiders (Latrodectus hasselti). We measured how exposure to temperatures common to invasive and native range habitats (exposure to 15 and 25°C, respectively) affected behavioral and life-history traits and trade-offs that may underlie fitness in an invasive population detected in 1995 in Japan and a native population from Australia. We found that the critical thermal minimum (CTmin) was higher in the invasive population from Japan than in the native population, but critical thermal maximum (CTmax) did not differ between populations. Compared to the invasive population, eggs from the native population had a longer development time and lower hatching success at 15°C. Both populations performed equally well at 25°C, as measured by egg development time and hatching success. Invasive juveniles tested at 15°C were faster to explore a novel environment and bolder compared to those tested at 25°C. In comparison, the native population showed faster average exploration, with no differences in boldness or exploration at the two development or testing temperatures. Overall, L. hasselti from Japan maintained hatching success and development across a wider temperature range than the native population, indicating greater thermal breadth and higher behavioral plasticity. These results support the importance of plasticity in thermal tolerance and behavior for a successful invasion under novel environmental temperatures.
温度挑战是外来物种在新环境中成功或失败的主要非生物原因之一，尤其是低温。在新的热环境中建立和繁殖会改变与生存、行为和适应度相关的特征。有人提出，热耐受性的可塑性或适应性可能使引入的物种得以繁荣，或者成功的入侵物种可能是那些在其原生栖息地的热幅宽包含了它们的新环境的物种。在这里，我们使用澳大利亚红背蜘蛛（Latrodectus hasselti）的本地和入侵种群来检验这些假设。我们测量了暴露于入侵和本地范围栖息地常见温度（分别暴露于 15 和 25°C）如何影响行为和生活史特征以及可能构成入侵种群基础的适应度权衡，该种群于 1995 年在日本被发现，而另一个则来自澳大利亚的本地种群。我们发现，来自日本的入侵种群的临界热最小值（CTmin）高于澳大利亚的本地种群，但种群之间的临界热最大值（CTmax）没有差异。与入侵种群相比，来自澳大利亚的本地种群的卵在 15°C 时发育时间更长，孵化成功率更低。与 15°C 相比，两个种群在 25°C 时的卵发育时间和孵化成功率均表现良好。在 15°C 下测试的入侵幼虫比在 25°C 下测试的幼虫更快地探索新环境，也更大胆。相比之下，在两个发育和测试温度下，本地种群的平均探索速度更快，而在大胆或探索方面没有差异。总体而言，来自日本的 L. hasselti 在更宽的温度范围内保持了孵化成功率和发育，表明其具有更大的热幅宽和更高的行为可塑性。这些结果支持了在新环境温度下成功入侵时热耐受性和行为可塑性的重要性。
