What’s for dinner? How novel phenotypes can influence prey selection in assassin bugs (Hemiptera: Reduviidae)

Frequency dependent predation theory suggests that novel phenotypes may be selected as prey at a different rate from the normal phenotype. We examined frequency dependant prey selection in conjunction with general versus specific predation. Our study examined the selection frequency of a novel prey item when introduced to two different species of Reduviidae. The white-spotted assassin bug, Platymeris biguttatus, is a generalist feeder, while the red-spotted assassin bug, Platymeris rhadamanthus, feeds primarily on the rhinoceros beetle (Coleoptera: Scarabaeidae) in the wild. We tested the hypothesis that these two species would respond differently when introduced to a novel prey phenotype. We predicted that the generalist feeders would be more likely to select the novel prey item while specific feeders will be less likely to choose a novel phenotype. The assassin bugs were fed Turkistan cockroaches, Blatta lateralis (Blattodea: Blattidae) for four weeks prior to the experiment. Assassin bugs were divided up into three replicates, with four assassin bugs in each cage. In each feeding cycle, one of the Turkistan roaches was painted with nail polish. These novel phenotypes were randomly assigned during the feedings. By comparing the rate at which the novel phenotype is selected as a prey item, we can identify patterns in prey choice. The implications for prey selection and predator choice will be discussed.