Cockroach fauna in the Ogasawara Chain Islands of Japan and analysis of their habitats.

A survey of cockroach fauna was carried out on the 3 inhabited islands of the Ogasawara chain island of Japan, namely, Chichijima island, Hahajima island and Iwo island. Seven species, namely, Periplaneta americana (Linnaeus, 1758), Periplaneta australasiae (Fabricius, 1775), Blattella lituricollis (Walker, 1868), Onychostylus vilis (Brunner von Wattenwyl, 1865), Supella longipalpa (Fabricius, 1798), Pycnoscelus surinamensis (Linnaeus, 1758) and Opisthoplatia orientalis (Burmeister, 1838), were collected on Chichijima island. Four species, namely, P. americana, P. australasiae, O. vilis and P. surinamensis were collected on Hahajima island and 6 species, namely, P. americana, P. australasiae, B. lituricollis, O. vilis, P. surinamensis and Neostylopyga rhombifolia were collected on Iwo island. This is the first record of N. rhombifolia and Onychostylus orientalis on the Ogasawara chain islands. Our study increases the recorded taxon of cockroaches on the Ogasawara from 3 families, 5 genera 10 species to 4 families, 7 genera, 12 species. A list of the cockroach species on Ogasawara islands reported to date as well as a key for their identification is also presented. Periplaneta americana and P. australasiae, being the dominant species, together with S. longipalpa, were collected mostly in the indoor environment, indicating their preference for this habitat. Pycnoscelus surinamensis, which is considered as an outdoor insect has been found in semi-household environments such as greenhouse and shed, indicating their new adaptation to the changing environment.