Rapid species radiations can provide insight into the process of speciation and diversification. Chrysoperla carnea, the common green lacewing, was once thought to be a single insect species with a near worldwide distribution. Species-specific vibrational mating songs revealed more than twenty morphologically cryptic species in the Chrysoperla carnea-group. Rapid diversification in this clade seems to have been driven, at least in part, by their precise substrate-borne vibrational duets performed prior to copulation. In this dissertation, I examine speciation in the Chrysoperla carnea-group by reconstructing the evolutionary history of the clade and identifying the genomic basis of a mating song trait critical to the maintenance of species boundaries in this group.
In Chapter 1, I assemble and annotate a de novo reference genome of Chrysoperla carnea sensu stricto, the first available for a neuropteran insect. In Chapter 2, I infer the evolutionary history of the carnea-group using reduced representation genome sequencing. Resolved species relationships indicate repeated phenotypic radiations, with multiple parallel evolution of ecomorphs on different continents. These analyses also reveal a history of hybridization in the clade. In Chapter 3, I identify a single large genomic region associated with the mating song feature ‘volley period,’ using QTL mapping. This genomic region contains several candidate genes for lacewing song phenotype, including the gene doublesex, which is critical to song production in Drosophila. Additionally, I demonstrate strong genetic linkage between volley period phenotype and preference for volley period. Overall, this dissertation advances our understanding of carnea-group lacewing diversification and speciation
