Host blood source was found to affect both the fecundity and the duration of the gonotrophic cycle of Aedes triseriatus. Mosquitoes were fed on restrained deer, chipmunks, squirrels, humans and suckling mice. Results showed that mosquitoes fed on chipmunks or squirrels, the major La Crosse virus vertebrate amplifier hosts, had greater fecundity but longer gonotrophic time intervals (approximately 2 more days per ovarian cycle) than mosquitoes fed on deer, which is a non-amplifier species. Results were similar for both first and second mosquito gonotrophic cycles. Application of these data to a model determining differential reproductive capacity showed a 24% reduction in the number of second cycle eggs laid by Ae. triseriatus taking the initial blood meal on amplifier species as compared to those taking the initial blood meal from deer. As only those uninfected mosquitoes that feed on an amplifier species have a chance of becoming orally infected and producing infected eggs, this reduced reproductive capacity reduces correspondingly the potential number of vertical infections that can be established during the amplification process.