title: Loss of flight promotes beetle diversification.
abstract: The evolution of flight is a key innovation that may enable the extreme diversification of insects. Nonetheless, many species-rich, winged insect groups contain flightless lineages. The loss of flight may promote allopatric differentiation due to limited dispersal power and may result in a high speciation rate in the flightless lineage. Here we show that loss of flight accelerates allopatric speciation using carrion beetles (Coleoptera: Silphidae). We demonstrate that flightless species retain higher genetic differentiation among populations and comprise a higher number of genetically distinct lineages than flight-capable species, and that the speciation rate with the flightless state is twice that with the flight-capable state. Moreover, a meta-analysis of 51 beetle species from 15 families reveals higher genetic differentiation among populations in flightless compared with flight-capable species. In beetles, which represent almost one-fourth of all described species, repeated evolution of flightlessness may have contributed to their steady diversification since the Mesozoic era.
authors.affiliation: Department of Forest Entomology, Forestry and Forest Products Research Institute, 1 Matsunosato Tsukuba, Ibaraki 305-8687, Japan. hiroshiikeda@affrc.go.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ikeda
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Teiji
authors.initials: T
authors.lastname: Sota
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D003062:Codon; D001517:Coleoptera / Q000235:genetics*; D004463:Ecology; D004777:Environment; D019143:Evolution, Molecular; D005426:Flight, Animal; D014644:Genetic Variation; D005843:Geography; D007313:Insecta / Q000235:genetics*; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D003062:Codon