Continuous variation in hind wing length of Galerucella grisescens (Coleoptera, Chrysomelidae, Galerucinae) and genetic basis of wing length determination

Dispersal ability is an important trait for insects that affects their survival and distribution ranges. In this study, we focused on variations in hind wing length in Galerucella grisescens (Joannis 1866) (Coleoptera, Chrysomelidae, Galerucinae). We surveyed frequencies of long-winged (LW) and short-winged or micropterous (SW) individuals in various localities in Japan and conducted crossing experiments using LW and SW individuals to clarify the genetic basis of wing length determination. The SW individuals were mainly found in central Honshu (Kanto, Chubu, and Hokuriku districts), while the LW individuals were widely distributed from Hokkaido to the Southwest Islands of Japan. Hybrid offspring derived from LW and SW parents exhibited hind wings of medium length, and the wing length was maternally affected. These results suggest that the hind wing morph of G. grisescens is determined by polygenic quantitative traits, and the gene(s) of interest may occur on the X-chromosome or other maternal factors.