Breeding Behaviors of the Endangered Prairie Butterfly Oarisma poweshiek (Lepidoptera: Hesperiidae) in Relation to Environmental Factors in an Ex Situ Conservation Setting

The Poweshiek skipperling Oarisma poweshiek (Parker, 1870) (Lepidoptera: Hesperiidae) is an endangered prairie obligate butterfly native to the north central United States and southern Canada. Conservation efforts for this species rely on ex situ approaches for population augmentation and reintroductions. As such, improving our understanding of the behaviors of Poweshiek skipperlings and maximizing their reproductive output in an ex situ setting are critical for the success of associated conservation initiatives. In this study, we examined the frequency of breeding behaviors exhibited by Poweshiek skipperlings in relation to various environmental factors: sunlight intensity (measured in lux), ambient temperature, and age. Sunlight intensity was a significant predictor of breeding behavior frequency, but we did not detect an effect of ambient temperature on breeding behavior. We also documented a generally negative relationship between age and breeding behavior frequency for both sexes. The results of our study underscore the importance of natural sunlight in encouraging breeding behaviors in an ex situ conservation environment. Ex situ observations also can help identify environmental conditions that promote high levels of Poweshiek skipperling activity, which could be used to optimize the timing of in situ population surveys.