Effect of thiodan on survival, behaviour and predatory performance of a spider, Plexippus paykulli (Savigny et Audouin, 1827).

Plexippus paykulli (Savigny et Audouin, 1827) is a jumping spider that has great potential to suppress insect pests of agricultural crops. In the present study effects of Thiodan (insecticide) on the survival, locomotion, insecticide avoidance behaviour and predation rate of P. paykulli were investigated. Thiodan caused 40% mortality at the recommended field rate concentration (5µl of insecticide /400 µl of water). P. paykulli did not avoid the surface treated with the Thiodan (1/4 th of recommended field rate). Calculated LD50 value was 8.23 µl (SE± 2.01). There was also no difference in resting time of Thiodan treated and control spiders. However, predation rate of Thiodan treated spiders was significantly reduced (up to70%) compared to the control spiders. We also observed change in the locomotory pattern and speed of the treated spiders. It is concluded that Thiodan affect locomotory pattern and reduces the predatory performance of studied species, so before recommending this insecticide for the IPM programme in the study area, its affects on the other beneficial organisms should be investigated.