Data from: The interactive effects of photoperiod and future climate change may have negative consequences for a wide-spread invasive insect

Increasing global temperatures may affect many ectotherms, including insects, although increasing temperatures are thought to benefit future populations through effects on adult size, fecundity, or populations. However, the way that temperature may interact with photoperiod is not well understood. We study this problem using the Asian tiger mosquito Aedes albopictus, an important worldwide invasive whose future spread is thought to be affected by changes in climate. We investigated how mass at maturity varied with temperature (21°C, 25°C) across short and long photoperiods, using laboratory populations from the extreme ends of this species’ current US range (Florida, New Jersey). These values were used to parametrize a model to predict optimal mass based on development times; the results of a second laboratory experiment under the same treatments were compared to model predictions. Warmer conditions shortened development times in females from all locations leading to either higher or lower mass depending on the photoperiod. We then used published mass–fecundity relationships to determine the consequences of mass on fecundity under our conditions. Under the majority of scenarios warming decreased predicted fecundity under long photoperiods, but proved beneficial under short photoperiods because the costs of fast development were offset by increased survival in the face of late-season freezing risk. However, fecundity was always low under short photoperiods, so the marginal benefit of warming appears negligible given its cost under long photoperiods when the majority of reproduction occurs. Thus, with northern range expansion, where colder weather currently limits this species, detrimental effects of warming on fecundity are likely, similar to those identified for mass. Unlike previous work that has shown benefits of a warming planet to insects like Aedes albopictus, our work predicts lower performance under warming conditions in summer across the current range, a prediction with implications for range expansion, disease dynamics and populations.

全球气温升高可能会对包括昆虫在内的诸多外温动物造成影响，尽管此前学界普遍认为，气温升高可通过影响成虫体型、繁殖力或种群动态，使未来种群获益。然而，气温与光周期的交互作用机制目前尚未得到充分阐释。本研究以全球重要入侵物种——白纹伊蚊（Aedes albopictus）为研究对象，其未来扩散范围被认为会受到气候变化的影响。我们利用采自该物种当前美国分布范围两端（佛罗里达州、新泽西州）的实验室种群，探究了在短、长两种光周期条件下，成虫成熟时的体重如何随温度（21℃、25℃）变化。我们将所得数据用于参数化一个基于发育时长预测最优体重的模型，并将相同处理条件下的第二项实验室实验结果与模型预测结果进行比对。温度升高缩短了所有地理种群雌蚊的发育时长，但其体重变化则因光周期不同而呈现升高或降低的趋势。随后，我们利用已发表的体重-繁殖力关联数据，分析了本研究条件下体重对繁殖力的影响。在多数情景下，气温升高会降低长光周期条件下的预测繁殖力，但在短光周期条件下却能带来益处——这是因为快速发育的代价，会因季节末期低温冻害风险下存活率的提升而得到抵消。但短光周期条件下的繁殖力始终处于较低水平，而多数繁殖事件均发生在长光周期环境中，综合来看气温升高的边际收益可忽略不计，因其在长光周期条件下会带来相应代价。因此，在当前受低温限制的北部扩张范围内，气温升高对繁殖力的负面影响或将出现，这与此前针对体重得出的结论一致。与此前认为气候变暖对白纹伊蚊等昆虫有益的研究不同，本研究预测，在当前分布范围内的夏季升温条件下，该物种的适合度会有所下降；这一预测对其种群扩张、疾病传播动态及种群存续均具有参考意义。