Spodoptera alkaloids

Johnson, N. D. and Bentley, B. B. 1988. Effects of dietary protein and lupine alkaloids on growth and survivorship of Spodoptera eridania. J. Chem. Ecol. 14, 1391-1403... 

Insects have evolved mechanisms to tolerate plant toxins. Such mechanisms enable them to use a plant as a food source that is avoided by other herbivores, and provides the herbivore with its own ecological niche.9 For example, insects may prevent accumulation of detrimental alkaloids in the hemolymph by efficient excretion. Larvae of Spodoptera littoralis (Lepidoptera, Noctuidae) feed freely on plants containing pyrrolizidine alkaloids that are rapidly excreted and only transiently detectable in the hemolymph. Even pyrrolizidine alkaloids directly injected into the hemolymph are efficiently excreted.48 The same has been observed... 

This MLA fraction was also tested for insecticidal activity against Spodoptera eridania and Musea domeStica, and was toxic to both. A previous study by Aiyar et al. had shown that MLA was the alkaloid responsible for causing the death of cattle feeding on Delphinium brownii in Western Canada (10) They also demonstrated that MLA had a neuromuscular blocking action in a rat phrenic nerve-diaphragm preparation, which was probably due to an effect on the nicotinic cholinergic receptor. The EC50 for this effect was 2.3 pM. 

Clay K, Cheplick GP. Effect of ergot alkaloids from fungal endophyte-infected gasses on fall armyworm (Spodoptera furgiperda). J Chem Ecol 15 169-182, 1989. 

Similarly it has been shown that the most potent norditerpenoid alkaloids acting as inhibitors of mammalian and insect cholinergic receptors have the C-l 8 anthranilic acid esterification, characteristic of the Delphinium norditerpenoid alkaloid methyllycaconitine (MLA), structurally-related to aconitine [40-42], MLA also had antifeedant effects against Spodoptera eridania with associated post-ingestive and toxic effects at doses within the effective antifeedant dose range of compound 30 [40], suggesting a similar antifeedant mode of action between MLA/aconitine and the C-20 diterpenoid alkaloids. 

The first scientific paper dealing with a non-alkaloid sesquiterpene polyol ester showing insect antifeedant activity was published by Wakabayashi et al. [128], who reported that celangulin (1), isolated from the ethyl ether extract of Chinese bittersweet root bark, exhibited activity against Spodoptera frugiperda (Noctuidae, Lepidoptera) larvae. Thus, addition of the compound in the diet at a concentration of 5 and 10 ppm, the average body weight of larvae was reduced to 61% and 37%, respectively. 

Regulation of the biosynthesis of secondary metabolites cannot be seen as separate from the role of these products for the plant. However, in most cases this role is not known. In the case of C. roseus an antifeedant activity against Spodoptora larvae has been reported for vinblastine and catharan-thine 49). A nematocidal effect has been reported for serpentine 50). Antifeedant activity against Spodoptera caterpillars for C. roseus leaf extracts has been described as well 49,51). Luijendijk et al. 52,53) found that besides alkaloids, also nonpolar compounds are involved in the antifeedant... 

Cornelius, W. W. Akeng a, T. Obiero, G. 0. Lutta, K. P. activities Antifeedant of the Erythrinaline alkaloids from Erythrina latissima against Spodoptera littoralis (Lepidoptera Noctuidae). Rec. Nat. Prod., 2009, 32, 96-103. 

Among some other quinoline alkaloids, N-methylflindersine was isolated firom rutaceous plants such as O. japonica and Fagara chalybea and showed antifeedant activity against insects Spodoptera exempta) [10]. Eduli-nine, on the other hand, isolated from Zanthoxylum simulans (Rutaceae), was shown to possess analgesic and anticonvulsive activities [11]. 

Pyrrolizidine alkaloids are feeding deterrents and insecticidal for many species of insects (Schneider, 1987 Wink, 1993b). Some insects, such as Melanchra persicariae and Spodoptera littoralis feed on Senecio vulgaris, which contains pyrrolizidine alkaloids, but do not sequester the alkaloids. The larvae are cryptically colored (Schneider, 1987). Certain insects appear to be able to excrete these alkaloids without harm. For example, senecionine (5), its A -oxide, and hydrolytic products, including retronecine (1), were found in the honeydew of the aphid Myzus persicae when this insect fed on Senecio vulgaris (Molyneux et al., 1990). 

Extracts from leaves of L. montanus, L. aschenbornii, L. stipulatus grown in Mexico showed insecticidal activity toward larvae of the Fall Armyworm (Spodoptera frugiperdd) [57]. The extracts of L. montanus and L. aschenbornii contain sparteine as the major constituent, while the major alkaloids in L. stipulatus extract are aphylline and an epiaphyUme-Uke alkaloid. This last one was found to be the most effective against larvae of S. frugiperda. Extracts of L. montanus and L. aschenbornii were found to have toxicity similar to sparteine [57]. 

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