Coccinella septempunctata

Attractive Compounds. While the defence chemistry of ladybird beetles has been extensively investigated, little is known about intraspecific communication. The role of chemical and behavioural cues has been described in mate recognition in Adalia bipunctata. Cuticular hydrocarbons, especially 7- and 9-methyltri-cosane seem to play an important role [301]. In Coccinella septempunctata, 2-isopropyl-3-methoxypyrazine 158 (see Scheme 17) accounting for the dis-... 

The framework of coccinelline-type alkaloids may be generated by linear combination of seven acetate units, as illustrated in Scheme 57 (330,336). An intermediate such as 456 would explain the existence of the different ladybug alkaloids. Support for the polyketide origin has been provided by feeding experiments ( " CHjCOONa and CHg COONa) with Coccinella septempunctata (330). 

Monocyclic Carotenoids. Eighteen carotenoid hydrocarbons have been isolated from the ladybird beetle Coccinella septempunctata. Amongst the minor components were detected small amounts of the new y-ring derivatives 3, 4 -didehydro-y.i/f-carotene (6), 7, 8 -dihydro-y,i/f-carotene (7), and 7, 8, 1T,12 -tetrahydro-y,i -carotene (8). 

A carotenoid unfortunately named neothxanthin, from the fish Neothunnus albacora, is considered to be e,e-caroten-3-ol (6) but has not been characterized fully.Further details of the absorption and mass spectra of the series of y-ring carotenoids obtained from the ladybird beetle Coccinella septempunctata have been published. It is unfortunate that the small amounts of material available did not permit determination of the chirality at C-6 of the y-ring (13). 

Three compounds containing a quinolizidine ring system have recently been isolated from beetles belonging to the family Coccinellidae. The first of these is coccinellin, C13H23NO, which appears to be an effective constituent of the defensive secretion of the common ladybird, Coccinella septempunctata L. Coccinellin is an N-oxide which can be reduced to the parent tertiary base, pre-coccinellin the latter is also present in the haemolymph of the insect. 

Marks, R. J. (1977) Laboratory studies of plant-searching behavior by Coccinella septempunctata L. larvae. Bull. Ent. Res., 67, 235-41. 

The ornate moth Utethesia ornatrix produces (i )-(-)-hydroxydanaidal (Figure 10.4) from pyrrolizidine alkaloids like monocrotaline N-oxide, and uses it as a sex attractant for females as the danaid butterflies do. The aphid Aphis jacobaeae also feeds on Senecio plants and stores these alkaloids. The ladybird Coccinella septempunctata (Plate 3) feeding on the aphids accumulates the pyrrolizidine alkaloids in turn, but does not accumulate cardiac glycosides (see earlier). 

Plate 3 The seven-spotted ladybird Coccinella septempunctata, which produces precoccinelline and coccinelline by reflex bleeding. 

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