2018 Volume 68 Issue 1 Pages 19-41
Ground beetles (Carabidae and Braconidae) are widely recognized as bioindicators, yet major questions about their biology remain unanswered. In particular, although hind wings are important for dispersal, few studies have examined them except in a few species of Carabinae. Here, we examined the morphology of the hind wings, flight muscles, and hind-wing-to-body-length ratio (HWBL), and the relationship between habitat and wing type. We conducted sampling in 2011–2013 using pitfall and aerial traps across a Satoyama landscape in Chiba Prefecture, central Japan. We analyzed the hind wings of 2,925 beetles belonging to 72 species and the body size of 4,883 of beetles in 78 species. We found 60 macropterous, eight brachypterous, two wing dimorphic, and two polymorphic species, but no apterous beetles. Considering the relationship between HWBL and flight capability, we postulated that the species with HWBL≤0.75 were flightless, while those with HWBL≥0.9 could probably fly. We documented three subtypes of brachypterous morphology: stick-shaped, shrunken, and elongated brachyptery. We also revealed the presence of wing polymorphic species. Among the subfamilies studied, Carabinae appeared to be at the most advanced stage of brachyptery, Pterostichinae showed great variation in the hind wings, Zabrinae and Harpalinae are probably active fliers, and one species of Callistinae showed developmental variation in the wingtip. We consider stick-shaped brachyptery to be the most advanced stage in the evolution of ground beetle flightlessness, because no stick-shaped brachypterous individuals were found in wing dimorphic or polymorphic species.
