The chemical defence of Doryphorina beetles (Coleoptera: Chrysomelidae)

Biosynthesis of a defensive insect alkaloid: epilachnene from oleic acid and serine.

“…While we were not able to detect free ethanolamine in the pupal hemolymph of E. varivestis, this amine has been identified in the defensive secretion of other beetles (6). Whether serine decarboxylation occurs before or after the oleic acid and serine moieties are joined, how the crucial amination step is accomplished, and when the fatty acid chain is shortened are among the questions that remain to be studied.…”

“…The epilachnene mass spectrum from the individual fed with L-[2-13C,15N]serine (6) provided evidence that this alkaloid's nitrogen atom is also serine derived. This spectrum showed a significant ionic abundance at m/z 269 (M + 2) compared with a very low abundance at m/z 269 in the mass spectrum of epilachnene.…”

How to Spoil the Taste of Insect Prey? A Novel Feeding Deterrent against Ants Released by Larvae of the Alder Leaf Beetle, Agelastica alni

“…[42] A further glutamic acid derivative, gl-glutamyl-ethanolamine (25), was detected in defensive secretions of the adult Chrysomelinae Labidomera trimaculata, Zygogramma suturalis, and Chrysolina coerulans. [41,43] These compounds are structurally closely related to 1, because each contains a g-conjugated glutamic acid unit.…”

“…This dipeptide is toxic to ants after oral uptake. [40,41] A similar dipeptide, g-l-glutamyl-l-(Z)-2-aminohex-3-enoic acid (24), was found in the defensive secretion of adult Platyphora kollari (Chrysomelinae). [42] A further glutamic acid derivative, gl-glutamyl-ethanolamine (25), was detected in defensive secretions of the adult Chrysomelinae Labidomera trimaculata, Zygogramma suturalis, and Chrysolina coerulans.…”

Chemical defense in Platyphora kollari Baly and Leptinotarsa behrensi Harold (Coleoptera: Chrysomelidae). Hypotheses on the origin and evolution of leaf beetles toxins

“…In contrast, the subtribe Chrysolinina is generally characterized by the production of cardenolides (Pasteels & Daloze 1977;Daloze & Pasteels 1979), although five Chrysolina species feeding exclusively on Hypericum perforatum secrete polyoxygenated steroid glycosides instead (Daloze et al 1985;Randoux et al 1990; Daloze et al 1991), whereas several Oreina species sequester pyrrolizidine alkaloids from their Asteraceae food plants, either alone (in Oreina cacaliae) or in admixture with cardenolides (see Pasteels et al 1995;Hartmann et al 1997, and references therein). In contrast, in the subtribe Doryphorina sensu Daccordi (Seeno & Wilcox 1982), the genus Leptinotarsa is characterised by defensive secretions containing amino acid derivatives, whereas two Calligrapha species produce cardenolides (Daloze et al 1986;Timmermans et al 1992). One species, Zygogramma suturalis is, so far, unique in simultaneously producing cardenolides and amino acid derivatives (Timmermans et al 1992).…”