THE PHYSIOLOGICAL COSTS OF FLIGHT CAPABILITY IN WING-DIMORPHIC CRICKETS

Nutritional indices, triglyceride levels and flight muscle development al profiles were compared between long-winged (LW) and short-winged (S W; flightless) morphs of the crickets Gryllus rubens Scudder and G. fi rmus Scudder. This was done to identify potential physiological costs of flight capability in adults. The LW morph of each species converted a lower proportion of assimilated nutrients into biomass (reduced ECD ) than did the SW morph. This documents increased respiratory metaboli sm in the LW morph. Triglyceride concentration was higher in LW vs. SW adults. This suggests that the elevated respiration in the LW morph m ay be at least partially due to the increased biosynthesis of this hig h energy substance. Preliminary data indicate higher respiration rates of LW functional vs. SW vestigial flight muscles. Collectively, these data suggest that the energetic cost of flight capability in adults r esults from biosynthesis of triglyceride flight fuel and flight muscle maintenance but not flight muscle growth. No flight muscle growth was observed in adults.