Meeting Abstract

80.2  Wednesday, Jan. 6  Wing damage and flight performance in dragonflies: Effects of area loss on force production and aerial predation COMBES, S.A.*; CRALL, J.D.; MUKHERJEE, S.; Harvard University scombes@oeb.harvard.edu

Age-related wing damage is common in flying insects, with accumulated tears and tattering often resulting in significant area loss. Aerodynamic theory predicts a resulting decline in flight performance, and previous studies have documented changes in biomechanical variables during simple flight assays. However, several studies have shown that these changes do not necessarily translate into increased energetic costs or decreased survival rates – thus, the impact of wing damage on wild insects remains unclear. We tested the effects of wing area loss on the ability of Libellulid dragonflies to produce flight forces and perform natural aerial behaviors. We first carried out a laboratory experiment designed to repeatedly elicit high force production. Dragonflies were dropped in mid-air and filmed with high-speed video as they attempted to arrest their fall and fly up towards a light. Drop tests were performed before and after symmetric wing area removal, with forewing and hindwing alterations performed on different groups. After wing area removal, dragonflies were less effective at producing vertical forces to arrest their fall, and their subsequent ascending flight was slower and less steep. To examine the relevance of these findings to more natural flight behaviors, we assessed aerial predation success of dragonflies in an outdoor artificial habitat, quantifying success rate before and after hindwing area removal. Our results suggest that wing damage does in fact compromise dragonfly flight performance, and highlights the importance of extending laboratory studies of locomotory performance to more complex, ecologically relevant behaviors.