Gregarine infection in Aedes triseriatus: Impact on behavior and vulnerability to predation

As larvae, Aedes triseriatus are preyed upon by Toxorhynchites rutilus in the southern part of their range. As a result, a number of experiments have been done to study the interaction between the two species. However, none of these studies have considered the impact of Ascogregarina barretti, a gregarine parasite of Ae. triseriatus, on these predator-prey interactions. The dynamics of parasite-mediated predator-prey interactions have been studied in a wide range of organisms. Such studies frequently find that parasitism of prey increases its vulnerability to predation. The study presented here found the reverse to be true of Ae. triseriatus parasitized by A. barretti. Prey infected by A. barretti had higher survivorship than uninfected prey, indicating that the parasite may be altering the behavior of its host and leading to decreased predation by T. rutilus.