D3301: From water born to airborne: The natural history of Samea multiplicalis and Elophila obliteralis

A majority of Lepidoptera are terrestrial, and they are very adapted to life on land. Yet there is a small percentage of Lepidoptera that have evolved within close proximity to water and that have taken on an aquatic or semi-aquatic lifestyle. Only about 0.5% of the165,000 known lepidopterans are aquatic, and the majority of these are found within the family Crambidae. Elophila obliteralis and Samea multiplicalis are respectively aquatic and semi-aquatic moths in the family Crambidae where the preimaginal stages (egg, larvae, pupa) undergo a portion of their development in the water. Neither have filamentous gills but possess other adaptations such as using silk to their advantage when feeding and forming leaf cases. The two species have a broad host range of aquatic plants, including invasive species such as water lettuce (Pistia stratiotes. Studies have shown these moths could play a role as a biological control agent for invasive species, but little is known about their natural history, development times and specific adaptations to living in an aquatic environment. In this study, S. multiplicalis and E. obliteralis were collected and reared in the laboratory on water lettuce to better understand the natural history of these species. We recorded their development times and described in detail their behavioral adaptations to living in an aquatic environment, including the use and application of their silk. We also for the first time provide high quality photographic material of each life stage of both species.