Thermal tendencies in OoencyrtusfecundusFerriere&Voegele (Hymenoptera: Encyrtidae), egg parasitoid of sunn pest

Insects are poikilothermes, hence environmentalfactors, and primarily temperature can affect their biological activities and behavior. In this study thermal range preferred by OoencyrtusfecundusFerrier &Voegelewas investigated by a device producing a thermal gradient from 16 to47ºC. Temperature of different parts of the arena was precisely recorded by eight thermometers entered the arena from marginal walls of the apparatus. Three entries were prepared in cold, middle and warm areas of the device. In order to exclude possible tendencies of the release point, experiment was done three times each from an entry. Twenty wasps were released each time and number of the parasitoids as well as current temperature of any part was recorded after 5, 15 and 30 minutes. The highest frequency of the wasp (89.25%) was occurred in a spectrum of 23.47-29.54 ºC while 46.66% of them were assembled in center of the arena where mean temperature was 26.03 ºC. Wasp's distribution was affected by release point as significant discrepancies were observed between all pairs of the experiments. The results revealed that the wasp searches for the sites withdesirable temperaturesby limited locomotionbut avoid further movements as soon as it finds tolerable temperature.