Histochemistry of flight muscles in the jamaican fruit bat, Artibeus jamaicensis : Implications for motor control

Two fast‐twitch fiber types are histochemically identified in the primary flight muscles of Artibeus jamaicensis . These are classified as type IIa and IIb according to an acid‐preincubation staining protocol for myosin ATPase. All fibers in the bat flight muscles exhibit relatively intense staining properties for NADH‐TR, suggesting a high oxidative capacity. The glycolytic potential of all fibers is rather low, as assessed by stains for alpha‐GPD. This two‐type histochemical profile appears to parallel biphasic electromyographic patterns observed in these muscles and leads us to propose that flight muscle histochemistry and activation are mediated by a “two‐gear” neuromuscular control system. In contrast, earlier studies on Tadarida brasiliensis demonstrate the existence of a “one‐gear” neuromuscular control system, exemplified by the presence of one fiber type. These observations are discussed with respect to the natural history and flight styles of several species.