DENSITY-DEPENDENT PHASE POLYMORPHISM AFFECTS RESPONSE TO ADIPOKINETIC HORMONE IN LOCUSTA

1. Haemolymph lipid levels were measured before and after injection of graded doses of corpus cardiacum (CC) extracts, and of synthetic adipokinetic hormone (AKH) I, to solitary and gregarious adult males of Locusta migratoria migratorioides. 2. Gregarious locusts showed higher resting lipid levels and a consistently higher increase of haemolymph lipids, 90-100 min after injection. 3. Haemolymph volume was lower in solitary than in gregarious locusts; therefore, the phase-dependent differences in haemolymph lipid levels and in adipokinetic response were not caused by differences in haemolymph volume. 4. The authors conclude that solitary locusts have lower haemolymph lipid levels and a less intense response to AKH than gregarious locusts.