Climate‐driven thermal opportunities and risks for leaf miners in aspen canopies
Climate‐driven thermal opportunities and risks for leaf miners in aspen canopies
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气候驱动的白杨树冠中潜叶虫的热机会和风险
DOI：
10.1002/ecm.1544
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发表时间：
2022
影响因子：
6.1
通讯作者：
Larkin, Beau G.
中科院分区：
文献类型：
--
作者：
Woods, H. Arthur;Legault, Geoffrey;Kingsolver, Joel G.;Pincebourde, Sylvain;Shah, Alisha A.;Larkin, Beau G.
在树冠中，入射的太阳辐射与树叶和树枝相互作用，在树叶内和树叶之间产生温差，为居住在树叶上的外温动物提供了热量机会和风险。虽然叶生物物理学和昆虫热生态学是很好的理解，很少有研究在单一系统中一起检查它们。我们研究了白杨林冠的温度变化，山杨，以及它对一种常见的食草动物，采叶毛虫的后果。我们在田间遮蔽叶片，并测量对叶温和幼虫生长和存活的影响。我们还估计了幼虫的摄食和生长的热性能曲线，并测量了上限致死温度。直接面对阳光照射的叶子达到最高温度，通常比环境空气温度高3-8°C。然而，辐照驱动的温度升高是短暂的，它们不会改变观察到的潜叶虫的生长速率。孵化器和升温实验表明，幼虫的性能在25至32°C之间达到峰值，在35至40°C之间下降到零，这取决于温度暴露的持续时间。1小时热休克期间的致死温度上限为42-43°C。当幼虫在早春活跃时，温度一般都低到足以将摄食和生长速率抑制在最大值以下，只有很少的估计矿井温度超过最佳温度。观察到的叶或矿的温度从未接近幼虫的致死温度上限。在我们的实验中，在这个地点，幼虫似乎有一个显着的热安全裕度;更紧迫的问题是热量不足。然而，关于矿井温度和幼虫性能曲线的详细信息使我们能够利用关于空气温度的长期数据集来估计未来性能的潜在变化和致命高温对幼虫的长期风险。这一分析表明，在过去20年中，幼虫的表现往往受到寒冷的限制，热应激的风险很低。未来的变暖将提高平均摄食率和生长率，但也会增加暴露在有害或致命高温下的风险。
In tree canopies, incoming solar radiation interacts with leaves and branches to generate temperature differences within and among leaves, presenting thermal opportunities and risks for leaf‐dwelling ectotherms. Although leaf biophysics and insect thermal ecology are well understood, few studies have examined them together in single systems. We examined temperature variability in aspen canopies,Populus tremuloides, and its consequences for a common herbivore, the leaf‐mining caterpillarPhyllocnistis populiella. We shaded leaves in the field and measured effects on leaf temperature and larval growth and survival. We also estimated larval thermal performance curves for feeding and growth and measured upper lethal temperatures. Sunlit leaves directly facing the incoming rays reached the highest temperatures, typically 3–8°C above ambient air temperature. Irradiance‐driven increases in temperature, however, were transient enough that they did not alter observed growth rates of leaf miners. Incubator and ramping experiments suggested that larval performance peaks between 25 and 32°C and declines to zero between 35 and 40°C, depending on the duration of temperature exposure. Upper lethal temperatures during 1‐h heat shocks were 42–43°C. When larvae were active in early spring, temperatures generally were low enough to depress rates of feeding and growth below their maxima, and only rarely did estimated mine temperatures rise beyond optimal temperatures. Observed leaf or mine temperatures never approached larval upper lethal temperatures. At this site during our experiments, larvae thus appeared to have a significant thermal safety margin; the more pressing problem was inadequate heat. Detailed information on mine temperatures and larval performance curves, however, allowed us to leverage long‐term data sets on air temperature to estimate potential future shifts in performance and longer‐term risks to larvae from lethally high temperatures. This analysis suggests that, in the past 20 years, larval performance has often been limited by cold and that the risk of heat stress has been low. Future warming will raise mean rates of feeding and growth but also the risk of exposure to injuriously or lethally high temperatures.