Isolation and identification of apolar metabolites of ingested 20-hydroxyecdysone in frass ofHeliothis virescens larvae

Abstract

A large amount of 20-hydroxyecdysone was orally administered to larvae of the tobacco budworm,Heliothis virescens, in order to investigate its detoxification mechanisms. Four major relatively nonpolar metabolites were isolated from their frass. These compounds were identified as the 22-linoleate, 22-palmitate, 22-oleate, and 22-stearate of 20-hydroxyecdysone using various forms of spectroscopy, including NMR. This is the first report of this type of metabolite from an insect.

Cannibalism of Helicoverpa zea (Lepidoptera: Noctuidae) from Bacillus thuringiensis (Bt) Transgenic Corn Versus Non-Bt Corn

“…Most of the species examined have been lepidoptera, due to the pre-eminence of this order among phytophagous pests. Some species are very tolerant, such as H. virescens (Kubo et al 1987), H. armigera (Robinson et al 1987), and S. littoralis (Blackford et al 1996). Other species, Cynthia cardui and Tyria jacobaeae, for example, are semitolerant (Blackford and Dinan 1997a), while others are highly susceptible, such as S. frugiperda, Pectinophora gossypiella (Kubo et al 1981(Kubo et al , 1983, Acrolepiopsis assectella (Arnault and Sláma 1986), A.…”

“…However, certain insect species remain unaffected by dietary phytoecdysteroids. This is the case for Heliothis virescens (Kubo et al 1987), Heliothis armigera (Robinson et al 1987), Spodoptera littoralis (Blackford et al 1996), and Lacanobia oleracea (Blackford and Dinan 1997b). These species have developed effective detoxification mechanisms against ingested phytoecdysteroids.…”

Distribution and metabolism of exogenous ecdysteroids in the egyptian cotton leafwormSpodoptera littoralis (lepidoptera: noctuidae)

“…Both Helicoverpa species (Family: Noctuidae) are able to feed on diets containing high levels of ecdysteroid without exhibiting any adverse effects (Robinson et al, 1987;Kubo et al, 1987) a phenomenon which has been attributed to the production and rapid excretion of ecdysteroid 22-fatty acyl esters. As a free C-22 hydroxyl group appears to be a requirement for moulting hormone activity (Bergamasco and Horn, 1980), conjugation at this position with a long-chain fatty acid probably represents a very efficient inactivation pathway.…”

Cannibalism of <I>Helicoverpa zea</I> (Lepidoptera: Noctuidae) from <I>Bacillus thuringiensis</I> (Bt) Transgenic Corn Versus Non-Bt Corn

“…Most of the species examined have been lepidoptera, due to the pre-eminence of this order among phytophagous pests. Some species are very tolerant, such as H. virescens (Kubo et al 1987), H. armigera (Robinson et al 1987), and S. littoralis (Blackford et al 1996). Other species, Cynthia cardui and Tyria jacobaeae, for example, are semitolerant (Blackford and Dinan 1997a), while others are highly susceptible, such as S. frugiperda, Pectinophora gossypiella (Kubo et al 1981(Kubo et al , 1983, Acrolepiopsis assectella (Arnault and Sláma 1986), A.…”

“…However, certain insect species remain unaffected by dietary phytoecdysteroids. This is the case for Heliothis virescens (Kubo et al 1987), Heliothis armigera (Robinson et al 1987), Spodoptera littoralis (Blackford et al 1996), and Lacanobia oleracea (Blackford and Dinan 1997b). These species have developed effective detoxification mechanisms against ingested phytoecdysteroids.…”