How has the environment shaped geographical patterns of insect body sizes? A test of hypotheses using sphingid moths
How has the environment shaped geographical patterns of insect body sizes? A test of hypotheses using sphingid moths
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DOI：
10.1111/jbi.13583
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发表时间：
2019-08-01
影响因子：
3.9
通讯作者：
Beck，Jan
中科院分区：
文献类型：
--
作者：
Beerli，Nicolas;Bartschi，Florian;Beck，Jan
我们绘制了鞘类飞蛾体型的地理格局，并对其纬度分布进行了调查。我们测试了关于它们可能的环境控制的假设，即温度的影响（负：温度大小规则或伯格曼规则；正：反伯格曼规则），食物供应，在极端天气和季节性下对饥饿的稳健性。地理位置旧大陆和澳大利亚/太平洋地区。方法整理950种鞘鱼的体型资料，并绘制其分布图。以体长为重点，我们绘制了100公里网格细胞中所有物种的中位数和最大尺寸。在比较方法中，我们在单变量和多变量模型下，通过将物种的大小与整个范围内遇到的平均环境条件相关联，测试了解释性假设的预测。我们通过逐步将系统发育信息的分类分类纳入分层随机截取混合模型来解释系统发育。结果中位体型具有明显的地理分布规律，在中东和亚洲热带地区种大，在温带和非洲热带地区种小。绝对纬度对体型变化的解释很小，但存在最大体型的纬向倾斜。物种的中位数大小与净初级生产力相关，支持食物供应假说，而其他假说的支持较弱。与系统发育相比，环境相关性对解释总体尺寸变化的贡献要小得多（即<10%）（包括系统发育导致模型解释了70%的变异性）。主要结论热带地区较大物种的直观印象是由较大的极大值形成的。体型中值与纬度的关系非常弱。大多数鞘蛾体型的地理差异可以用它们的系统发育历史来解释。NPP和森林覆盖与体型呈正相关，这支持了食物供应允许更大体型进化的观点。
AimWe mapped the geographical pattern of body sizes in sphingid moths and investigated latitudinal clines. We tested hypotheses concerning their possible environmental control, that is, effects of temperature (negative: temperature size rule or Bergmann's rule; positive: converse Bergmann rule), food availability, robustness to starvation during extreme weather and seasonality.LocationOld World and Australia/Pacific region.MethodsBody size data of 950 sphingid species were compiled and related to their distribution maps. Focusing on body length, we mapped the median and maximum size of all species occurring in 100 km grid cells. In a comparative approach, we tested the predictions from explanatory hypotheses by correlating species' size to the average environmental conditions encountered throughout their range, under univariate and multivariate models. We accounted for phylogeny by stepwise inclusion of phylogenetically informed taxonomic classifications into hierarchical random‐intercept mixed models.ResultsMedian body sizes showed a distinctive geographical pattern, with large species in the Middle East and the Asian tropics, and smaller species in temperate regions and the Afrotropics. Absolute latitude explained very little body size variation, but there was a latitudinal cline of maximum size. Species' median size was correlated with net primary productivity, supporting the food availability hypothesis, whereas support for other hypotheses was weak. Environmental correlations contributed much less (i.e. <10%) to explaining overall size variation than phylogeny (inclusion of which led to models explaining >70% of variability).Main conclusionThe intuitive impression of larger species in the tropics is shaped by larger size maxima. Median body sizes are only very weakly related to latitude. Most of the geographical variation in body size in sphingid moths is explained by their phylogenetic past. NPP and forest cover correlate positively with the body size, which supports the idea that food availability allowed the evolution of larger sizes.