A convenient estimation of the sources of sweet potato weevils, Cylas formicarius (Fabricius) (Coleoptera: Brentidae), in recently invaded areas in Japan, by random amplified polymorphic DNA technique

RAPD-PCR was used to clarify the genetic properties of the sweet potato weevil, Cylas formicarius, which was collected from several of the Southwest Islands, Ogasawara Islands, Muroto City and Yakushima Island in Japan. PCR amplification of C. formicarius DNA using three primer sets, i.e., T13/T13, T05/T05, and T01/T07, resulted in products of several different sizes among individuals and primer sets. The 393 wild weevils tested were classified into 27 distinctive categories by combining the three patterns detected for each weevil. The frequency of these categories varied both among islands and among collection sites within the same island. The categories confirmed for weevils from Muroto City and Yakushima Island were detected only in those from Okinawa-Hontou Island and the more northern islands of the Southwest Islands. C. formicarius from these islands probably invaded Muroto City in 1995 and Yakushima Island in 1997.