Evolution of Specialization: A Phylogenetic Study of Host Range in the Red Milkweed Beetle (Tetraopes tetraophthalmus)
Evolution of Specialization: A Phylogenetic Study of Host Range in the Red Milkweed Beetle (Tetraopes tetraophthalmus)
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DOI：
10.1086/659948
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发表时间：
2011-06-01
影响因子：
2.9
通讯作者：
Agrawal, Anurag A.
中科院分区：
文献类型：
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作者：
Rasmann, Sergio;Agrawal, Anurag A.
专业化在大多数食草昆虫谱系中很常见，食草昆虫是地球上最多样化的生物群体之一。为了解决如何和为什么专业化是保持在进化的时间，我们假设，植物防御和其他生态属性的潜在宿主植物将预测的性能专家根食草食动物（红马利筋甲虫，Tetraopes tetraophthalmus）。使用比较系统发育和功能性状的方法，我们评估了决定昆虫寄主范围跨越18种马利筋。幼虫存活率下降，从真正的主机，马利筋的系统发育距离，这表明适应植物性状驱动专业化。在几个根性状的测量，只有cardenolides（有毒的防御化学品）与幼虫的生存，cardenolides也解释了系统发育的距离效应在遗传控制的多元回归分析。此外，马利筋与其他Tetraopes甲虫有已知的联系，比缺乏Tetraopes草食动物的物种更好的主机，和马利筋的特定叶面积值（叶功能和栖息地关系的性状）类似于A。丁香是较好的寄主，而不是具有分歧值的物种。因此，我们可以得出结论，系统发育距离是一个综合措施的表型和生态属性的马利筋物种，特别是防御cardenolides，它可以用来解释专业化和限制主机转移随着进化的时间。
Specialization is common in most lineages of insect herbivores, one of the most diverse groups of organisms on earth. To address how and why specialization is maintained over evolutionary time, we hypothesized that plant defense and other ecological attributes of potential host plants would predict the performance of a specialist root-feeding herbivore (the red milkweed beetle, Tetraopes tetraophthalmus). Using a comparative phylogenetic and functional trait approach, we assessed the determinants of insect host range across 18 species of Asclepias. Larval survivorship decreased with increasing phylogenetic distance from the true host, Asclepias syriaca, suggesting that adaptation to plant traits drives specialization. Among several root traits measured, only cardenolides (toxic defense chemicals) correlated with larval survival, and cardenolides also explained the phylogenetic distance effect in phylogenetically controlled multiple regression analyses. Additionally, milkweed species having a known association with other Tetraopes beetles were better hosts than species lacking Tetraopes herbivores, and milkweeds with specific leaf area values (a trait related to leaf function and habitat affiliation) similar to those of A. syriaca were better hosts than species having divergent values. We thus conclude that phylogenetic distance is an integrated measure of phenotypic and ecological attributes of Asclepias species, especially defensive cardenolides, which can be used to explain specialization and constraints on host shifts over evolutionary time.