QUANTIFYING THE VENOM DOSE OF THE SPIDER CUPIENNIUS-SALEI USING MONOCLONAL-ANTIBODIES

The variation in venom dose with prey size of the neotropical wanderin g spider Cupiennius salei was examined experimentally. Monoclonal anti bodies were raised against the venom toxins of C. salei. Mab 9H3, reco gnizing the main toxin CSTX-1, was used to quantify the venom by enzym e-linked immunosorbent assay (ELISA). Crickets (Acheta domesticus) in four size classes were randomly offered to sixteen mature female spide rs at 14 d intervals. The prey items were removed from spiders five mi nutes after the initial bite and subsequently homogenized for ELISA me asurements. The quantity of venom expended was significantly related t o the size of prey, ranging from 0.15 mu l for the smallest (100 110 m g) to 1.53 mu l for the largest (600-660 mg) crickets. Adaptations to prey size were also reflected in capturing behavior. None of the small est, but almost 50% of the largest crickets were wrapped in silk follo wing the spiders bite. Some other behavioral features may reduce the e nergetic costs of venom production, In 22% of the smallest crickets no venom was detectable, with the majority showing mechanical damage as a result of fang contact. This indicates, that C. salei does not rely exclusively on its venom when feeding on small prey. Some other aspect s such as the site of the bite and the speed of paralyzation and their consequences associated with the amount of expended are discussed. (C ) 1998 Elsevier Science Ltd. All rights reserved.