Local adaptation and evolutionary potential of multi-host parasites.

摘要

In this thesis I test predictions relating to two problems in parasite ecology. First, I test whether host species range influences the likelihood of finding local parasite adaptation and second, whether the abundance of a given host species locally determines parasite traits or fitness. Using a novel statistical analysis and a critical literature review, I found that parasites with many host species were less likely to be adapted to local populations of single host species, after correcting for differences in experimental approaches and other factors that may have confounded results. Using empirical approaches and detailed field studies, I found that the water mite Limnochares americana Lundblad, a parasite with many dragonfly hosts, appears to track an abundant host, Leucorrhinia frigida Hagen, and has higher fitness on this host compared to a less abundant host Nannothemis bella (Uhler). Together, these findings indicate that use of multiple host species has implications for testing local adaptation theory.