Yamawaki Yoshifumi, Kainoh Yooichi
Department of Biology, Faculty of Science, Kyushu University, Japan.
Zoolog Sci. 2005 May;22(5):563-70. doi: 10.2108/zsj.22.563.
We presented the tachinid fly Exorista japonica with moving host models: a freeze-dried larva of the common armyworm Mythimna separata, a black rubber tube, and a black rubber sheet, to examine the effects of size, curvature, and velocity on visual recognition of the host. The host models were moved around the fly on a metal arm driven by motor. The size of the larva, the velocity of movement, and the length and diameter of the rubber tube were varied. During the presentation of the host model, fixation, approach, and examination behaviours of the flies were recorded. The fly fixated on, approached, and examined the black rubber tube as well as the freeze-dried larva. Furthermore, the fly detected the black rubber tube at a greater distance than the larva. The rubber tube elicited higher rates of approach and examination responses than the rubber sheet, suggesting that curvature affects the responses of the flies. The length, diameter, and velocity of host models had little effect on response rates of the flies. During host pursuit, the fly appeared to walk towards the ends of the tube. These results suggest that the flies respond to the leading or trailing edges of a moving object and ignore the length and diameter of the object.
粘虫的冻干幼虫、黑色橡胶管和黑色橡胶片，以研究大小、曲率和速度对宿主视觉识别的影响。宿主模型由电机驱动的金属臂围绕苍蝇移动。改变幼虫的大小、移动速度以及橡胶管的长度和直径。在展示宿主模型期间，记录苍蝇的固定、接近和检查行为。苍蝇会固定、接近并检查黑色橡胶管以及冻干幼虫。此外，苍蝇在比幼虫更远的距离就能检测到黑色橡胶管。橡胶管引发的接近和检查反应率高于橡胶片，这表明曲率会影响苍蝇的反应。宿主模型的长度、直径和速度对苍蝇的反应率影响很小。在追逐宿主期间，苍蝇似乎朝着管子的两端走去。这些结果表明，苍蝇对移动物体的前缘或后缘做出反应，而忽略物体的长度和直径。
