First Comprehensive Description of Salt Marsh Skipper (Panoquina panoquin) (Hesperiidae) Natural History: Confirmation of a Second Host Plant In Virginia Salt Marshes

Abstract

In a rapidly changing world, a complete understanding of a butterfly species' natural history and information about each of the life stages from egg to adult is more important than ever. For many butterfly species, records on life history strategies and habitat requirements are often lacking, especially for immature stages. The salt marsh skipper (Panoquina panoquin) is one such example of an understudied species. As a specialist of salt marshes, studying these immature stages is important for understanding how this species interacts with and uses its habitat. The goal of this study was to fill in gaps in our knowledge of the natural history and habitat preferences of the salt marsh skipper. We conducted field surveys of ovipositing females in three Virginia coastal marshes (5 sites) between May and October 2021. In doing so, we characterized host plant use and oviposition microhabitat. We also tracked eggs and larvae to assess survival in relation to natal host plant. We observed the oviposition of 32 eggs, 15 of which were on Distichlis spicata and 17 on Spartina alterniflora. All life stages used S. alterniflora, including feeding by larvae, confirming this species as a novel host plant. S. alterniflora was the most abundant grass in egg plots and we found no difference between random and egg plot microhabitat. In the microhabitat analysis, we found that host plant use was largely associated with the more abundant of the two grasses in a plot. D. spicata, however, was preferred in cases of up to 26% more S. alterniflora cover relative to D. spicata. Lastly, we documented an overall successful hatching rate of 19% with equal risk of egg mortality on both host plants. While our results still indicate that the salt marsh skipper is a specialist, it has a broader range of habitat and might be able to cope with marsh decline better than previously thought.