Evolutionary trends in the wing shape of the family Dolichopodidae (Diptera)

Abstract

A comparative analysis was conducted on wing-vein landmarks on 81 species belonging to 27 genera of 11 subfamilies of the family Dolichopodidae for estimating relationships between wing shape and phylogeny. Wing shape was investigated by using the geometric morphometric technique. We used principal components analysis in order to description of wing shape variation among species and subfamilies. To estimate a degree of homoplasy wing shape variation were mapped onto the specific-level phylogenetic tree based on the COI gene (810 characters). Pagel's lambda was used to quantify the phylogenetic signal in wing traits. The analyses demonstrated that the differences among subfamilies were generally associated with changes of R1 length, movement of posterior crossvein and tips of R4+5 and M1+2. The comparative analysis with outgroup taxon allowed for the determination of the evolutionary trends in the family and undertaking a character polarity of wing characters. The analysis revealed that wing shape and size have high phylogenetic signal. The result of our study demonstrated the monophyly of Dolichopodidae subfamily; however there was some degree of homoplasy: the species of the subfamilies, which were not closely relates (Hydrophorinae, Medeterinae and Sciapodinae) tend to have a similar wing shape. The functional significance of the evolutionary trends is discussed.