Geographic variation of elytral color in the sweet potato weevil, Cylas formicarius (Fabricius) (Coleoptera: Brentidae), in Japan

抄録

To use elytral color morphs of Cylas formicarius as a genetic marker in its eradication using the sterile insect technique, the geographic distribution of the morphs was examined in the three main infested areas of Japan (Central Ryukyus, Southern Ryukyus, and Ogasawara Islands). In addition to the two known color morphs in Japan (bluish elytra (BE) and greenish elytra (GE)), the piceous elytra (PE) was found mainly in the Southern Ryukyus at low frequency. The color morph frequencies varied between the Central and Southern Ryukyus and between locations within the two areas, while only BE was found in the Ogasawara Islands. PE would be useful for genetically marking sterile weevils to be released. Similarly, GE would be useful in some islands where GE is rarely or not found. BE frequencies on two islands in the Central Ryukyus (Amami and Okinawa) and two islands in the Southern Ryukyus (Miyako and Ishigaki) in 2006–2007 were higher than in 2002–2003.