Physical factors in host selection of the parasitoid fly, Exorista japonica Townsend (Diptera : Tachinidae)

抄録

We investigated the infiuence of physical factors, i.e., texture, color, shape and size, on host selection of the tachinid fiy, Exorista japonica, using various host models in choice tests. Female flies approached and examined equally semi-cylindrical black rubber tubes, paper tubes and silicone tubes of the same size, 4.0 ×1.0×0.5cm, but oviposited only on the black rubber tubes. They examined black tubes more frequently than white tubes. They did not examine black rubber sheets but they did examine black rubber cubes. Also, female fiies preferred models of small diameter (0.8>1.0>1.2cm) and those that were longer (2.0<4.0<6.0cm). These results indicated that female fiies recognized a target's color before examination, and the texture and curvature of targets by tarsal examination. E, japonica females appear to have a host size preference.