Genome size increase in the phytophagous ladybird beetle Henosepilachna vigintioctomaculata species complex (Coleoptera: Coccinellidae)

Abstract

This study reports genome size (C-value) estimates for seven species of ladybird beetles (Coleoptera: Coccinellidae) in Japan using flow cytometry. The results demonstrated genome sizes of 1.0-1.4Gb in four closely related phytophagous ladybird beetles belonging to the Henosepilachna vigintioctomaculata species complex. These values were approximately two times larger than that of a congeneric phytophagous ladybird beetle H.vigintioctopunctata (0.66Gb), and of two very distantly related common carnivorous ladybird beetles, Harmonia axyridis (0.46Gb) and Coccinella septempunctata (0.42Gb). These lines of evidence suggest that rapid and large genome size increase occurred just after the branching of the common ancestor of the H.vigintioctomaculata species complex from other ladybird species.