GENETIC CRITERIA FOR ESTABLISHING EVOLUTIONARILY SIGNIFICANT UNITS INCRYANS BUCKMOTH

Buckmoths (Hemileuca spp.) are day-flying saturniid moths with diverse ecologies and host plants. Populations that feed on Menyanthes trifol iata, known commonly as Cryan's buckmoths, have been found in only a f ew bogs and fens near eastern Lake Ontario in New York and near Ottawa in Ontario, Canada. Because of their unique ecological traits, geogra phic isolation from other Hemileuca populations and the small number o f sites they occupy, there is concern that the Cryan's buckmoth popula tions are phylogenetically distinct and should be protected. The Cryan 's buckmoths have not yet been taxonomically described and do not appe ar to have clear distinguishing morphological characters. Both molecul ar genetic traits (allozymes and mitochondrial DNA sequences) and an e cologically based character (host performance) were investigated to de termine whether these populations possess fixed diagnostic characters signifying genetic differentiation from other eastern Hemileuca popula tions. Such differences would merit separate conservation management a s an evolutionarily significant unit. Our studies showed that the Crya n's buckmoths clearly belong to the Hemileuca maia species group, but they could not be readily distinguished from other members of that gro up by means of molecular genetic techniques. There were no fixed diffe rences in alleles or haplotypes distinguishing any of the populations or species, suggesting-recent divergence. Nonetheless, in the host-pla nt performance experiment only the Cryan's buckmoth larvae were able t o develop on M. trifoliata, a significant difference from other Hemile uca larvae tested. The Cryan's buckmoth appears to be unique in host p erformance and warrants protection and management as an evolutionarily significant unit. In cases such as this where groups appear to have r ecently diverged, investigations into ecologically significant traits may provide indicators of conservation significance as reliable as mol ecular genetic markers.