context-dependent effects of ranaviral infection on northern leopard frog life history traits上下文相关的ranaviral感染对北方豹蛙生活史的影响特征.pdfVIP

Context-Dependent Effects of Ranaviral Infection on Northern Leopard Frog Life History Traits 1 1 2 ` 1 Pierre Echaubard , Kevin Little , Bruce Pauli , David Lesbarreres * 1 Genetics and Ecology of Amphibians Research Group (GEARG), Department of Biology, Laurentian University, Sudbury, Canada, 2 Environment Canada, Science and Technology Branch, National Wildlife Research Centre, Carleton University, Ottawa, Canada Abstract Pathogens have important effects on host life-history traits, but the magnitude of these effects is often strongly context- dependent. The outcome of an interaction between a host and an infectious agent is often associated with the level of stress experienced by the host. Ranavirus causes disease and mortality in amphibian populations in various locations around the world, but most known cases of ranaviral infection have occurred in North America and the United Kingdom. While Ranavirus virulence has been investigated, the outcome of Ranavirus infection has seldom been related to the host environment. In a factorial experiment, we exposed Northern leopard frog (Lithobates pipiens, formerly Rana pipiens) tadpoles to different concentrations of Ranavirus and investigated the effect of host density on certain life-history traits, namely survival, growth rate, developmental stage and number of days from virus exposure to death. Our results suggest a prominent role of density in driving the direction of the interaction between L. pipiens tadpoles and Ranavirus. We showed that increasing animal holding density is detrimental for host fitness as mortality rate is higher, day of death earlier, development longer and growth rate significantly lower in high-density tanks. We observed a linear increase of detrimental