2006 Volume 46 Issue 3 Pages 126-137
We observed oviposition behavior of the ectoparasitoid wasp, Euplectrus separatae that parasitized on the common army worm Pseudaletia separata. The female wasps always oviposit on the dorsal surface of three segments from the 3rd thoracic to the 2nd abdominal segment of the host. This oviposition behavior may be important to escape from the aggressive defense behavior of the host at the time of oviposition. We attempted to develop a new method because several experiments out of analyzed oviposition behavior patterns in E. separatae seemed to be appropriate as teaching materials for high school students. It is very difficult to practice all of the experiments on this wasp oviposition behavior in a class at high school but it is possible to carry out one or two parts of the experiments.
High school students in Aichi prefecture have observed the oviposition behavior of E. separatae. And they got the following conclusions as follows. (1) An extract of host frass by ethyl ether gave rise to the searching behavior of a female wasp. (2) As the female wasp found out her host, she mounted the posterior part of the host abdomen. As soon as the host moved forward, the female wasp also moved forward on the host’s body. The female wasp laid eggs after stopping near the host head (the first segment of abdomen). (3) The peristaltic movment of the host was the trigger for the female wasp to move forward.
Every student understood the meaning of the experiments on the wasp’s oviposition behavior. And most of the students could reach to the desired conclusions. Moreover as the time schedule is suitable, we judged this experiment of the wasp’s oviposition behavior is suitable for high school’s biology class.
