Meeting Abstract
Bat wings contain muscle and elastin fibers embedded in thin, compliant membranes. These structures are present in all bat species studied to date and are thought to affect the extensibility and camber of the wing during flight. Determining the structure and arrangement of these fibers is critical to understanding the aerodynamic performance of the membrane. Using histological techniques, we examined the trailing edge of Seba’s short-tailed fruit bat, Carollia perspicillata. In this species, the spanwise, caudalmost edge of the armwing comprises two layers of collagen surrounding an array of muscle cells and a large elastin fiber, composed of small fibrils. We examined the arrangement of the muscle cells and elastin fiber along the length of the trailing edge of the armwing, and investigated the mode of attachment of both tissue types at its proximal (hind limb) and distal (digit V) ends. Many muscle cells originate at the tibia, run spanwise along the trailing edge, and insert within the membrane. The large elastin fiber at the trailing edge widens (35μm to 265μm) rostrocaudally as it extends distally. The presence of muscles near the trailing edge suggests that C. perspicillata has some active control of this part of the wing membrane. The muscles might provide proximal stiffness when contracted or reduce skin looseness during upstroke. The large elastin bundle could act as a “hem” that prevents tearing while providing stability and durability. It may also help fold the wing during upstroke or keep the trailing edge taut, reducing flutter throughout the wingbeat cycle. Studying the morphology of the trailing edge of bat wings can inform our understanding of how skin is modified for flight and improve the design of compliant, membranous materials that encounter aerodynamic forces.
