Hyperlipaemic response of topically applied synthetic neuropeptides in the plant bug Iphita limbata Stål (Pyrrhocoridae: Heteroptera)

In the present investigation, two different methods viz., injection and topical application methods were employed for applying synthetic neuropeptides, Pyrrhocoris apterus adipokinetic hormone (Pyrap-AKH) and Locusta migratoria adipokinetic hormone-1 (Locmi-AKH-1). The hyperlipaemic activities of the synthetic neuropeptides were determined and compared. Both injection and topical application increased the levels of lipids in the haemolymph was dose dependent. Haemolymph lipid increase induced by Pyrap-AKH (27%) and Locmi-AKH-1 (46%) were dose dependent, hyperlipaemic response was maximal when 10 and 6 pmol of Pyrap-AKH-1 and Locmi-AKH-1 were applied by injection, and however gradual decrease was noticed with higher concentrations of both the synthetic hormones. The maximal hyperlipaemia induced by topically applied Pyrap-AKH and Locmi-AKH-1 is 25 (19%) and 15 pmol (41%) respectively.