Choice of Oviposition Site by Gray Treefrogs: the Role of Potential Parasitic Infection

The role of potential infection by parasitic trematodes in the choice of oviposition site choice by gray treefrogs, Hyla versicolor, was examined in a randomized experiment using 25 experimental pools. Treatment pools containing low (five snails) or high (10 snails) densities of either infected or uninfected trematode vector Pseudosuccinea columella were compared with control pools containing no P. columella. Treatments had significant effects on the number of gray treefrog eggs deposited in pools. Compared to control pools, fewer eggs were laid in all treatment pools, either because fewer pairs laid eggs, or fewer eggs were laid per visit. Pools containing infected P. columella also had fewer eggs deposited relative to pools containing uninfected P. columella. The gray treefrog, H. versicolor, can discriminate between oviposition sites, based on the species present and the potential for infection. Choice of oviposition site can be a mechanism that determines the composition of ecological communities as well as influencing parental reproductive success. Our results emphasize the importance of disease agents in shaping patterns of distribution, and they underscore the importance of understanding how potential hosts may use behavior to mitigate infection risk.