Micro- and macroevolutionary trade-offs in plant-feeding insects

A long-standing hypothesis asserts that plant-feeding insects specialize on particular host plants because of negative interactions (trade-offs) between adaptations to alternative hosts, yet empirical evidence for such trade-offs is scarce. Most studies have looked for microevolutionary performance trade-offs within insect species, but host use could also be constrained by macroevolutionary trade-offs caused by epistasis and historical contingency. Here we used a phylogenetic approach to estimate the micro- and macroevolutionary correlations between use of alternative host-plant taxa within two major orders of plant-feeding insects: Lepidoptera (caterpillars) and Hemiptera (true bugs). Across 1,604 caterpillar species, we found both positive and negative pairwise correlations between use of 11 host-plant orders, with overall network patterns suggesting that different host-use constraints act over micro- and macroevolutionary timescales. In contrast, host-use patterns of 955 true bug spe...长期以来，学界存在一项经典假说：植食性昆虫之所以特化于特定寄主植物，是因为其对不同寄主的适应性之间存在负相互作用，即适应性权衡（trade-offs），但此类权衡的实证证据却极为匮乏。既往多数研究均聚焦于昆虫物种内部的微进化性能权衡，然而寄主利用模式亦可受到上位性（epistasis）与历史偶然性（historical contingency）所介导的宏观进化权衡的制约。本研究采用系统发育分析方法，对两类主要植食性昆虫类群——鳞翅目（Lepidoptera，幼虫俗称毛虫）与半翅目（Hemiptera，即真蝽类）——在利用不同寄主植物类群时的微进化与宏观进化相关性进行了估算。在1604种毛虫样本中，我们发现11个寄主植物目之间的利用模式存在正负双向的两两相关性，整体网络模式显示，不同的寄主利用制约因素分别在微进化与宏观进化时间尺度上发挥作用。与之相对，955种真蝽类的寄主利用模式则……