ADIPOKINETIC NEUROPEPTIDES AND FLIGHT METABOLISM IN 3 MOTH SPECIES OFTHE FAMILIES SPHINGIDAE, SATURNIIDAE AND BOMBYCIDAE

Methanolic extracts from corpora cardiaca of three moth species, Hippo teon eson (Sphingidae), Imbrasia cytherea (Saturniidae) and Bombyx mor i (Bombycidae) show adipokinetic activity in conspecific bioassays. Ha emolymph carbohydrates in these moths are not affected. These extracts are also active in heterologous bioassays: haemolymph lipids are incr eased in Locusta migratoria, whereas a small effect on haemolymph carb ohydrates was observed in Periplaneta americana. Therefore, locusts ca n be used to monitor adipokinetic activity in corpora cardiaca from mo th extracts during isolation. The three moth species possess an adipok inetic peptide with the same retention time on reversed phase high per formance liquid chromatography (RP-HPLC) as a peptide isolated previou sly from Manduca sexta, which was code-named Mas-AKH. H. eson contains a second active peak with a similar retention time on RP-HPLC as the hypertrehalosaemic peptide isolated previously from Helicoverpa tea, c ode-named Hez-HrTH. Both synthetic peptides, Mas-AKH and Hez-HrTH, pro duce an adipokinetic effect in the three experimental moth species. In H. eson, the haemolymph concentration of Mas-AKH or Hez-HrTH needed t o elicit a maximum hyperlipaemic response is about 20 to 30 nM. Flight behaviour in the three moth species is quite different: H. eson is a good hovering flyer, I, cytherea is a comparatively bad flyer and B. m ori males show only degenerate flight movements during their mating da nce. Haemolymph lipid levels in H. eson decrease drastically during 15 min of flight and return to pre-flight levels in a subsequent rest pe riod. The amount of lipids metabolized during flight is 10.9 mg/g x hr . Haemolymph carbohydrate levels drop during flight, but remain low du ring the 45 min of recovery. Haemolymph lipids in ''dancing'' males of B. mori remain constant. In individuals, however, which have low init ial lipid levels in the blood, lipid concentrations increase significa ntly in a subsequent 15 min rest period after ''dancing''. Metabolic c hanges during flight in I. cytherea were not investigated due to this species' poor flight performance.