Systematics and evolution of predatory flower flies (Diptera: Syrphidae: Syrphinae ) based on exon-capture sequencing
Description
Syrphidae, one of the most species-rich dipteran families, provides important ecosystem services such as pollination, biological control of pests, recycling of organic matter, redistributions of essential nutrients, among others. Flower fly adults show a common feeding strategy on pollen and nectar, but their larval feeding habits are strikingly diverse. In the present study high-throughput sequencing was used to capture and enrich exons as a genome reduction method for the first time for any Diptera group. With the help of the BaitFisher software, we developed a new bait kit (SYRPHIDAE1.0) to target 1945 CDS regions belonging to 1312 orthologous genes. This new bait kit was successfully used to exon-capture the targeted loci in 121 flower fly species across the different subfamilies of Syrphidae. We analyzed different amino acid and nucleotide data sets (1302 loci and 154 loci) with the Maximum Likelihood and the Multispecies Coalescent approaches. Our maximum-likelihood and coalescent-based analyses resolved highly supported similar topologies, although the degree of the SRH (global stationary, reversibility and homogeneity) conditions varied greatly between amino acid and nucleotide data sets. The sisterhood of Pipizinae and Syrphinae is recovered in all our analyses, confirming a common origin of taxa feeding on soft-bodied arthropods. Based on our results, we define Syrphini stat.rev. to include the genera Toxomerus and Paragus. Our divergence estimate analyses with BEAST inferred the origin of the Syrphidae in the Lower Cretaceous and the diversification of predatory flower flies occurred around the K-Pg boundary.