No Wolbachia infection was detected in Drosophila elegans collected from the wild in the Ryukyu Islands, Japan

Drosophila elegans is a tropical and subtropical species distributed in southeast Asia and breeds on flowers of morning glory (Ipomoea spp.), trumpet (Brugmansia candida) and turmeric (Cucurma domestica) (Okada and Carson 1982; Sultana et al. 1999; Yoshida et al. 2000). Natural host plants of D. elegans are Ipomoea in the Ryukyu Islands, Japan. A male of D. elegans stays singly on a flower and shows territorial behavior; when another male visits, he chases and kicks the competitor, and pushes him out of the flower. In contrast, when a female visits the flower to lay eggs, he courts her. Two morphs are found in this species: black morphs from the Ryukyu Islands and Taiwan and brown morphs from southern China, Philippines, Indonesia, and New Guinea (Bock and Wheeler 1972; Okada and Carson 1982; Lemeunier et al. 1986; Hirai and Kimura 1997). Reproductive and behavioral manipulation by Wolbachia is reported in many insect taxa, including D. melanogaster (Kose and Karr 1995; Riegler et al. 2005; De Crespigny et al. 2006). However, it is less clear whether Wolbachia infection affects reproduction and other biological processes in D. elegans. Although Bourtzis et al. (1996) reported no Wolbachia detection in a laboratory strain of brown morph of D. elegans that was collected from Baguio City, Luzon, Philippines, there is no attempt to detect Wolbachia in freshly collected D. elegans flies, in our literature search. The present study attempted to detect Wolbachia in D. elegans (black morph) freshly collected from the wild on Okinawajima Island, Iriomote Island and Ishigaki Island, the three largest islands of the Ryukyu Islands.