A NEW METHOD FOR IMMUNOLOGICALLY MARKING PREY AND ITS USE IN PREDATION STUDIES

We introduce a new method for immunologically examining predator gut c ontents. It differs from previously described gut content analyses bec ause it does not require the development of prey-specific antibody pro bes. Instead, insect prey were marked with a readily available antigen , rabbit immunoglobulin G (IgG). We then assayed predators that had fe d on IgG labeled prey with an enzyme-linked immunosorbent assay (ELISA ) using goat anti-rabbit IgG. Of the predator species that fed on the IgG labeled prey, 98.8% of those with chewing mouthparts scored positi ve for IgG 1 h after feeding. Our prey-labeling ELISA was less efficie nt for detecting IgG prey remains in predators with piercing/sucking m outhparts. Only 29.5% of these individuals scored positive for rabbit IgG in their guts Ih after feeding. An additional study was conducted to measure the retention time of IgG-labeled prey in the guts of two s pecies of predators with chewing mouthparts. Results from this experim ent showed that the retention time varied depending on the predator an d prey species examined. Results from these studies indicate that this marking technique could have widespread use for analyzing the gut con tents of predators with chewing mouthparts, but it has limited applica tion for those predators with piercing/sucking mouthparts.