FURTHER DEVELOPMENT FOR TESTING THE EFFECTS OF PESTICIDES ON WOLF SPIDERS

Based on preliminary guidelines of the ''Biologische Bundesanstalt fur Land- und Forstwirtschaft'' (BBA, Germany) for testing the effects of pesticides on wolf spiders (genus Pardosa, Lycosidae, Araneae), two t est series were carried out with the pesticides Karate (a.i. lambda-cy halothrin) and a noname product. At start of the test the pesticides w ere applied onto spiders and a sand substrate with an application appa ratus. Thereafter, the mortality, the behavior, and the feeding rate w ere observed up to 14 days. Ninety-eight percent of the tested individ uals belonged to the species Pardosa amentata. The results of the Kara te experiments indicated a considerably higher reaction for males than for females. The aggression of the spiders proved to be a stress fact or when the vessel was inhabited by more than one spider and caused hi gher mortality in individuals treated with pesticides. Spiders raised from cocoons in the laboratory were in general less sensitive than ani mals collected in the field and accustomed to laboratory conditions. E xperiments performed with the noname pesticide in different seasons re vealed that the sensitivity of the animals was influenced by their age . The parameters of mortality, behavior, and feeding rate proved to pr ovide data adequate for evaluating the lethal and sublethal effects of the substances examined, The results suggest that the test method may be improved by (i) using spiders raised from cocoons in laboratory, ( ii) using fine gauze to prevent the escape of food flies, (iii) testin g in the same season when application of the pesticide is planned in t he field, (iv) using one animal per test vessel to avoid cannibalism a nd intraspecific stress, (v) providing additional feedings to avoid ca nnibalism, and (vi) assessing effects of chemicals on both sexes separ ately. Summarized, the modified test method is suggested as an adequat e method for testing the effects of pesticides on wolf spiders (Pardos a sp.). Use of the test during the registration proceeding is proposed as part of the testing program for effects of pesticides on beneficia l arthropods. (C)1995 Academic Press, Inc.