The Philippines is a possible source of the Bactrocera dorsalis complex species (Diptera, Tephritidae) occasionally collected in the Ryukyu Islands of Japan; analyses of mitochondrial DNA

The Oriental fruit fly, Bactrocera dorsalis (Hendel), was eradicated from all Japanese territories in 1986; however, because neighboring countries remain infested by this or closely related species of the B. dorsalis complex, a small number of flies occasionally fly into the Ryukyu Islands of southwestern Japan. In order to examine the geographic origins of these flies, we compared restriction-banding patterns of the PCR-amplified mitochondrial 12S ribosomal RNA gene (rDNA) fragment (300bp-long) among 455 specimens collected in the Ryukyu Islands, Taiwan, and the Philippines, and detected from fruits imported from the Philippines and Continental China and intercepted at Narita International Airport. Of five banding patterns detected using the restriction enzyme MseI, one pattern was observed only from insects originating in the Philippines and the Sakishima region in the southwestern part of the Ryukyu Islands. In phylogenetic analysis based on the sequence obtained in this and previous Studies (1, 138 bp-long mitochondrial DNA fragment from 16S to 12S rDNA), insects showing this banding pattern were tightly grouped with B. philippinensis Drew and Hancock endemic to the Philippines. Based on the results, we discussed the possibility that the fruit flies might have flown into the Sakishima region directly from the Philippines.