The Indiana bat (Myotis sodalis) is a federally endangered bat species found in the eastern United States. Populations of this species have declined steadily since regular surveys began, despite extensive conservation efforts. It remains at risk because a significant proportion of the population hibernates in a small number of caves and mines, and they are highly susceptible to human and natural disturbance.
The identification of any genetically differentiated groups of M. sodalis that may require independent conservation measures is critical to the development of federal and state management plans. Researchers are using molecular methods to examine levels of genetic variation, current levels of genetic structure and gene flow among populations, and the presence of discrete evolutionary lineages. Studies on winter populations using mitochondrial DNA have identified four groups of genetically distinct populations, including a large group of populations in the Midwest encompassing the majority of known hibernacula. Another smaller group of populations was found in the Appalachians, and two groups were found in New York. Overall, levels of mitochondrial DNA diversity were high in most populations, with the exception of three populations in New York (comprising the two Northeastern population groups) which were colonized more recently than populations in other parts of the range.
Further studies on winter populations using nuclear DNA (microsatellites) are necessary to confirm the presence of the population groups identified using mitochondrial DNA, and clarify sex-specific patterns of dispersal. In addition, we need to estimate effective population size, and independently assess levels of genetic diversity within populations. Additional analyses of summer populations using both mitochondrial and nuclear DNA will allow us to define the geographic extent of interacting populations, and to describe the linkage between summer breeding habitat and hibernacula.
Because Indiana bats are rarely encountered in large numbers, obtaining enough tissue samples for population genetic analyses is extremely challenging. We would be grateful for any samples collected, and they will be used to provide important context and background for the management of this declining bat species.