Van Dievel Marie, Stoks Robby, Janssens Lizanne
Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium
Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium.
J Exp Biol. 2017 Nov 1;220(Pt 21):3908-3915. doi: 10.1242/jeb.158899. Epub 2017 Aug 24.
While heat waves will become more frequent and intense under global warming, the ability of species to deal with extreme weather events is poorly understood. We investigated how a heat wave influenced growth rate and investment in two immune components (phenoloxidase activity and melanin content) in larvae of two damselfly species, and Late instar larvae were kept at 18°C (i.e. their average natural water temperature) or under a simulated long heat wave at 30°C. To explain the heat wave effects, we quantified traits related to energy uptake (food intake and growth efficiency), energy expenditure (metabolic rate measured as activity of the electron transport system, ETS) and investment in energy storage (fat content). The two species differed in life strategy, with having a higher growth rate, growth efficiency, ETS activity and fat content. In line with its preference for cooler water bodies, the heat wave was only lethal for However, both species benefited from the heat wave by increasing growth rate, which can be explained by the higher increase in food intake than metabolic rate. This may also have contributed to the increased investment in energy storage and immune components under the heat wave. This mediatory role of food intake indicates the critical role of food availability and behaviour in shaping the impact of heat waves. Our results highlight the importance of including behavioural and physiological variables to unravel and predict the impact of extreme climate events on organisms.
在全球变暖的情况下，热浪将变得更加频繁和强烈，但人们对物种应对极端天气事件的能力却知之甚少。我们研究了热浪如何影响两种豆娘幼虫的生长速度以及在两种免疫成分（酚氧化酶活性和黑色素含量）上的投入，这两种豆娘分别是[具体物种1]和[具体物种2]。末龄幼虫被饲养在18°C（即它们自然水体的平均温度）或30°C的模拟长期热浪环境中。为了解释热浪的影响，我们量化了与能量摄取（食物摄入量和生长效率）、能量消耗（以电子传递系统（ETS）的活性来衡量的代谢率）以及能量储存投入（脂肪含量）相关的特征。这两个物种在生活策略上有所不同，[具体物种1]具有更高的生长速度、生长效率、ETS活性和脂肪含量。与它偏好较凉爽水体的习性一致，热浪仅对[具体物种2]具有致命性。然而，两个物种都因热浪而提高了生长速度，这可以通过食物摄入量的增加高于代谢率的增加来解释。这也可能促成了在热浪下能量储存和免疫成分投入的增加。食物摄入量的这种中介作用表明了食物可获得性和行为在塑造热浪影响方面的关键作用。我们的结果凸显了纳入行为和生理变量以阐明和预测极端气候事件对生物影响的重要性。
