Dakota Skipper Butterfly
I recently read a study about the Dakota skipper. The Dakota skipper is a small butterfly, with a wingspan of around one inch. Coloration is variable between the sexes with the upper wing surface of males a towny-orange to brown while females are a darker brown and spotted. The underside of males is dusty yellow-orange and females gray-brown with spots.
Dakota skippers used to be common in its native range which was roughly southeastern Saskatchewan, southern Manitoba, North and South Dakota, Minnesota, Iowa, and northern Illinois. As some of you know, the Dakota skipper is now listed as threatened under the Endangered Species act.
The biology and ecology of the Dakota skipper is poorly understood. For example, it is known that the larvae feed on grasses and grass-like plants, but they have not been observed in the wild. Research conducted by the Minnesota Zoo and University of Minnesota found some interesting differences in how species of grass influence larva growth and survival. They offered five species of native grasses (big bluestem, little bluestem, sideoats grama, porcupine grass, and prairie dropseed) to the larvae along with two introduced grasses (smooth brome and Kentucky bluegrass). They found the highest survival and shortest time to adulthood was on porcupine grass and prairie dropseed. The other native grasses were considered “medium” quality. Those that fed on smooth brome and Kentucky bluegrass did poorly.
The invasion of native prairie by smooth brome and Kentucky bluegrass is extensive. It has been hypothesized that the loss of native prairie coupled with the degradation of the prairie by these invasive introduced grasses is a factor in the species decline. This research seems to support that hypothesis. Prairie dominated by smooth brome and Kentucky bluegrass may be “ecological traps” to Dakota skipper recovery
The road to recovery for the Dakota skipper is going to be challenging. But gaining a better understanding of how different grasses influence larval growth and survival is an important step in better understanding the biology and ecology of the species and help to better focus recovery efforts.