Altizer, Sonia M

S 3RD INTERNATIONAL BUTTERFLY ECOLOGY AND EVOLUTION SYMPOSIUM CRESTED BUTTE, COLORADO, USA AUGUST 1998 Altizer, Sonia M. Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota 55108 USA. Host migration and the prevalence of a protozoan parasite in monarch butterfly populations Seasonal migration is exhibited by many groups of animals, and may exert strong effects on host-parasite interactions. Among populations of monarch butterflies infected with the protozoan parasite, Ophryocystis elektroscirrha, I have found that disease prevalence is inversely related to host migratory distance. Long-distance movement by monarchs may directly reduce disease prevalence if infected hosts are less likely to successfully migrate. Migration may also select for increased host resistance or decreased parasite virulence if heavily infected hosts are unable to migrate and survive between reproductive intervals. Using a series of cross-inoculation experiments, I have shown that host and parasite strains from different populations vary, with resistance highest and virulence lowest in the population that migrates the farthest distance. To assess the genetic basis for these differences in host resistance, I constructed a line cross experiment using parental and F1-hybrid lines from two North American monarch populations. As predicted, families derived from the longest-distance migrants were more resistant to disease strains from both populations. In addition, parasite strains were less able to infect the F1-hybrid crosses compared to hosts from either parental population. These results suggest that loci with both additive and non-additive effects are responsible for genetic divergence in host resistance, and that novel host genotypes in general may be more likely to resist infection. Anthony, N.M., Ganser, D., Gelembiuk, G. & ffrench-Constant, R.H. Department of Entomology, University of Wisconsin-Madison, Madison WI 53706 USA. Conservation genetics of the Karner blue butterfly (Lycaeides melissa samuelis) The Karner blue butterfly Lycaeides melissa samuelis, currently recognized as one of several subspecies of the more widespread Melissa blue butterfly L. melissa, was recently listed as federally endangered. A number of factors are believed to have led to the dramatic decline of the Karner blue, the most important being the fragmentation and loss of its native habitat. Remaining populations are thus widely separated, increasing the probability of local extinction in the absence of colonization from neighboring areas. Although this butterfly has been the subject of intense conservation efforts, little if anything is known of its population genetic structure. Moreover, its taxonomic status remains unclear. We are therefore interested in: (1) assessing the phylogenetic position of the Karner blue in relation to other closely related butterflies and (2) examining genetic variation within and among Karner blue populations. To address these aims, we have developed a set of DNA-based markers including the A+T rich region and COI/COII genes from the mitochondrial genome as well as several nuclear microsatellite loci. Results