DETOXIFICATION STRATEGIES OF 2 TYPES OF SPIDERS REVEALED BY CYPERMETHRIN APPLICATION

In order to compare the detoxification capacities of two species of sp iders, Linyphia triangularis and Pardosa prativaga were exposed to a c ommonly used pesticide, cypermethrin (a chlorinated pyrethroid). Two d etoxification enzyme systems - glutathione S-transferase (GST) and glu tathione peroxidase (GSH-Px) - were assayed as biomarkers. The two spe cies of spiders have different life-styles and eat different food, and in our experiment were at different stages of their life-cycle. There fore, differences in detoxification strategies could be expected. From our results, we suggest two different strategies. L. triangularis had a generally high basal level of GST, which could be further induced b y exposure to cypermethrin. The basal activity of GSH-Px was relativel y low, and no response to toxic exposure could be traced. Thus, this e nzyme plays only a minor role in the detoxification process of cyperme thrin in L. triangularis. In P. prativaga, a low basal GST activity wa s found. However, the basal level of GSH-Px was comparable to that of L. triangularis. A significant rise in GSH-Px activity (with t-butyl-h ydroxyperoxide as substrate) was apparent 12 hours after exposure. Thi s may indicate that P450 enzyme systems are involved in the cypermethr in metabolising process in P. prativaga. In addition, GSH-Px activity (with H2O2 as substrate) could be traced in P. prativaga but not in L. triangularis, indicating that a true peroxidase system is active in P . prativaga.