Measuring the Sensitivity of an Indirect Predator Gut Content ELISA: Detectability of Prey Remains in Relation to Predator Species, Temperature, Time, and Meal Size,

The gut contents of three species of insect predators that were fed either a variable or a fixed number of pink bollworm eggs but held at variable time and temperature regimes were assayed by an indirect enzyme-linked immunosorbent assay (ELISA). The sensitivity and efficacy of the monoclonal antibody-based ELISA was dependent on the predator species examined. Small predators were more immunoresponsive to the ELISA than large predators. Furthermore, the assay sensitivity was dependent on the number of prey consumed, elapsed time after feeding, and temperature at which the predators were held. The smaller predator species retained recognizable traces of prey remains for longer periods than larger predator species. The ELISA efficacy decreased with increasing ambient temperature. A series of regression equations have been developed to estimate the median detection interval of prey in a predatorʹs gut that takes into account the predator species examined, the quantity of prey consumed, and ambient after-meal temperature.