The relations of adipokinetic response and body lipid content in locusts (Locusta migratoria migratorioides) with special reference to phase polymorphism

Adipokinetic response, as expressed in an increase of haemolymph lipids after injection of adipokinetic hormone, and total body lipid content were assessed in crowded (gregarious) and isolated (solitary), as well as in newly aggregated and newly separated adult males of Locusta migratoria migratorioides. Both the adipokinetic response and lipid content of the body were higher in crowded than in isolated locusts, but changes of density did not exert a parallel effect on these two characteristics. In spite of some correlation, the adipokinetic hormone-induced hyperlipaemic response did not depend solely on body lipid content. Therefore, the differential adipokinetic response of crowded and isolated locusts is a valid phase characteristic which seems to be affected by both phase-dependent differences in body lipid content and phase-dependent differences unrelated to body lipid content.