Potential impacts on Japanese fauna of canestriniid mites (Acari: Astigmata) accidentally introduced with pet lucanid beetles from Southeast Asia

Abstract

To develop a risk-assessment system for small organisms accidentally introduced with imported organisms, we investigated as a first case study parasitic canestriniid mites, which have been imported into Japan via pet lucanid beetles from Southeast Asia. We collected mites from pinned specimens of Japanese lucanids collected before 1999—when the Japanese government lifted a ban on the import of the beetles—and living mites from imported and native lucanid beetles collected after that. No foreign canestriniid was found on any of the native Japanese beetles. Because the mites collected from imported beetles were different from Japanese species, we conclude that the foreign mites have not yet established wild populations in Japan. However, because the Japanese mites migrate between hosts without host physical contact, introduced mites are assumed to be able to migrate from a foreign to Japanese host. In fact, possible contamination was observed in pet shops. We observed host switching in only one direction: Southeast Asian Canestrinia nr spectanda switched to Japanese Dorcus rectus, but Japanese Coleopterophagus berlesei never switched to Indonesian D. titanus. The foreign mites reproduced between 15°C and 25°C, suggesting that the mites could survive in mountainous sites in southern Japan and at low elevations in northern Japan. The ability of foreign parasitic canestriniids to infect and survive on Japanese hosts at temperatures characteristic of much of Japan leads us to conclude that these mites present a potential risk to Japanese endemic canestriniids as well as to native Japanese lucanids.