The investigators will study the phylogeny and geography of host associations among populations of Papilio zelicaon (Lepidoptera) that differ in the host plants they use in northwestern United States and southwestern Canada. The proposed work will use the broad range of umbelliferous species fed on by P. zelicaon to relate the intraspecific geographic patterns of host use to phylogeny. Objective 1 of the proposed work will test for differences in oviposition preference and specificity among females from populations that are oligophagous. The oviposition preference and specificity trials will show the geographic pattern for variation in oviposition preference and specificity among females tested. Objective 2 will take advantage of molecular techniques to analyze mitochondrial DNA and allozyme variation and construct a phylogeny of host use the same populations used in objective 1. In objective 3 the same techniques will be used to show the number of times a novel host (fennel, Foeniculum vulgare) has been colonized, and the extent to which fennel-feeding populations have diverged from native host populations. Together, these 3 objectives will provide a better understanding of how phylogeny and geography interact to produce regional patterns of host specificity in phytophagous insects.
