FLIGHT-MUSCLE FATTY-ACID BINDING-PROTEIN SYNTHESIS IN JUVENILE AND ADULT FORMS OF THE DESERT LOCUST, SCHISTOCERCA-GREGARIA

The flight muscle of mature adult desert locusts contains large amounts of a fatty acid binding protein (FABP). The protein, which is absent at the beginning of the adult stage, accumulates in muscle cytosol during the first 2 weeks after metamorphosis. In insects treated with metamorphosis controlling hormones and anti-hormones, the intracellular concentration of FABP was determined with enzyme-linked immunosorbent assays and electron microscopical/immunogold labeling techniques. FABP content was found to be similar in both sexes of normal adults and in precocious adults. No FABP, however, was found in last instar nymphs, methoprene induced supernumerary nymphs and azadirachtin induced over-aged nymphs. The results indicate that FABP synthesis does not occur prior to metamorphosis, but is always initiated in differentiated adult flight muscle. FABP synthesis in adult muscle, however, is not directly stimulated by any hormone from the brain or adjacent endocrine glands.