Utilization of lipid for flight and reproduction in Spodoptera litura (Lepidoptera: Noctuidae)

Abstract

Abstract. Research of the physiological traits of a long-distance migratory insect, the common cutworm Spodoptera litura, in rela tion to flight and reproduction, was focused on triacylglycerol (TG) levels and their fatty acid composition.Tethered flight experiments demonstrated that three-day old male moths can fly more than 20 h. Among eight identified fatty acids of which the adult TG is composed, the ratios of the following unsaturated fatty acids, palmitoleic acid (C 16:1), oleic acid (C 18:1), linoleic acid (C 18:2) and linolenic acid (C 18:3), gradually declined with longer flight duration. On the other hand, the TG levels of non-flown males reared for ten days on only water, were the same as those of three-day old males after 12 hr of flight, but the ratios of these unsaturated fatty acids in TG's remained nearly unchanged. These results suggest that the unsaturated fatty acids in TG are mainly used as a flight energy source.As ovarian development in females of this species occurs shortly after adult emergence, long-distance migratory capacity has been regarded as highly unlikely. In fact, ovarian development was completed within three days after adult emergence and females laid eggs thereafter. During this three day period TG increased in the ovary, accompanied by increasing ratios of unsaturated fatty acids in the TG's and the ovary eventually occupied most of the abdomen, in spite of a nearly constant level of TG in the abdomen and unchanged ratio of its unsaturated fatty acids. These facts support the transfer of TG from the fat body to the ovary, and further suggest that the mature females utilize the TG deposited in the ovaries as a flight energy source. Then if they migrate a long distance, they use residual TG after flight for egg production.

Analysis of the lipids mobilized by adipokinetic hormones in the firebug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

“…It seems there is at least a partial specificity of individual locust AKHs for certain FAs, with Locmi-AKH-I preferentially mobilizing unsaturated FAs (mostly linoleic acid) and AKH-II and AKH-III saturated FAs (mostly stearic) (Tom ala et al, 2010). This accords with the Murata & Tojo (2002) finding that in locusts unsaturated FAs in TGs are mainly used as an energy source during flight, and that Locmi-AKH-I is more involved in lipid mobilization during flight than Locmi-AKH-II and Table 2). The bars represent SD, n = 3 for haemolymph samples and n = 12 for FB samples.…”

Factors influencing flight potential of Choristoneura conflictana

“…Metabolism of lipids, carbohydrates and amino acids provides energy to power flight muscles ( Judge et al , 1991;Sappington et al , 1995;Murata & Tojo, 2002 ). Lipids, gained through larval ( Coll & Yuval, 2004 ) or adult feeding ( Wheeler, 1996;Hanski et al , 2006 ), are efficiently metabolized and are commonly used as an energy source by insects that disperse over great distances ( Judge et al , 1991;Haunerland, 1997 ).…”

The effect of flight on reproduction in an outbreaking forest lepidopteran

“…This dichotomy supports the assumption that mating results in increased egg production (Outram, 1971; Loher et al , 1987; Wheeler, 1996; Adams, 2000), even when flight is a factor. The main sources of energy for flight in insects are unsaturated fatty acids found in triacylglycerol (Murata & Tojo, 2002). Fatty acids that are not used during flight are transferred to the ovaries post‐flight (Murata & Tojo, 2002).…”

“…The main sources of energy for flight in insects are unsaturated fatty acids found in triacylglycerol (Murata & Tojo, 2002). Fatty acids that are not used during flight are transferred to the ovaries post‐flight (Murata & Tojo, 2002). If this occurs in C. conflictana , resources transferred to the ovaries after flight may be the reason for the increase in potential fecundity of flown and subsequently mated females in the present study.…”