Collaborative Research -- Mating Signals and Demographic Divergence: Species Comparisons and an Experimental Test

Lay概要Cocroft、Hunt和WoodMating信号可以在物种形成过程的早期发生分歧，但尚不清楚信号分歧是在物种形成过程中起直接作用，还是其他过程(如生态专门化)的副产品。我们的目标是确定交配信号在一组以植物为食的昆虫多样化中的作用。Enchenopa binotata树蝉物种复合体由9个物种组成，这些物种是北美各种乔木和灌木的专家。大量证据表明，这一群体的物种形成是一系列向新寄主植物转移的结果。宿主转移改变了生活史的时间，再加上宿主的高度保真度，允许特征上的差异，从而提高在新宿主上的表现。我们的研究将通过减少祖先和新寄主植物种群之间的基因流动来检验交配信号的差异在物种形成中的重要性这一假说。我们的项目将包括：(1)对现存的9个Enchenopa binotata物种的振动交配信号进行比较研究；(2)将物种内和物种之间的信号变化模式与DNA序列差异模式进行比较；以及(3)确定在实验寄主移位的种群中是否发生了信号和生活史特征的差异。这项研究将为交配信号和分歧之间的关系提供补充图片，不仅在完全分化的物种中，而且在寄主植物小种形成的早期阶段的谱系中。这项研究的结果将加强我们对物种形成的基本了解，并可能提供实际好处，例如更好地理解农业害虫是如何在新的寄主物种上形成的。

Lay SummaryCocroft, Hunt and WoodMating signals can diverge early in the process of speciation, but it is unclear whether signal divergence plays a direct role in speciation or is a byproduct of other processes such as ecological specialization. Our goal is to determine the role of mating signals in the diversification of a group of plant-feeding insects. The Enchenopa binotata species complex of treehoppers consists of nine species that are specialists on various trees and shrubs in North America. Considerable evidence suggests that speciation in this group occurred as a result of a series of shifts to novel host plants. A host shift alters life history timing, which, in combination with high host fidelity, allows divergence in traits that enhance performance on a novel host. Our research will test the hypothesis that divergence in mating signals is important in speciation by reducing gene flow between populations on ancestral and novel host plants. Our project will integrate (1) a comparative study of vibrational mating signals in the nine extant Enchenopa binotata species; (2) comparison of patterns of signal variation within and among species with patterns of DNA sequence divergence; and (3) determination of whether divergence in signals and life history traits has occurred in experimentally host-shifted populations. This research will provide a complementary picture of the relationship between mating signals and divergence not only in fully differentiated species, but also in lineages in the early stages of host plant race formation. Results of this research will enhance our basic understanding of speciation, and may provide practical benefits such as an improved understanding of how agricultural pests become established on novel host species.