Larvae of the silver-spotted skipper (Epargyreus clarus; Hesperiidae), exhibit two interesting behaviors: they construct shelters from leaves of their leguminous host plants (Lind et al. 2001), and they forcefully eject their frass pellets (fecal matter) great distances away from their shelters (Weiss 2003 ). We are investigating the process through which larvae are able to build shelters that are almost invariant in shape and size, and are also studying the evolutionary history and ecological role of frass ejection behavior. 

Larvae belonging to many disparate lepidopteran families eject their frass, and the behavior has likely evolved independently a number of times. We have carried out field and lab studies to test three hypotheses regarding the ecological role of frass ejection: deterrence of natural enemies; maintenance of a hygienic environment; and preservation of space within the shelter. Our results suggest that elimination of chemical cues for natural enemies is a driving force behind the evolution of frass ejection behavior in skipper caterpillars; hygiene and crowding are less important in this system. We are also investigating the ecological implications of waste disposal in a range of animal taxa; hence, FAECOLOGY, or defecation ecology!

We enjoy bringing our charsimatic caterpillars into pre-school and elementary classrooms in the area. They are a great way for kids to learn about the butterfly life cycle, and to practice their observation skills - it's fun to watch a caterpillar build a shelter or fling a frass pellet! (Kids and Caterpillars)