Effects of plant-derived compounds on larvae of a blow fly species that causes secondary myiases: laboratory studies.

No-choice and binary-choice bioassays were used to test the effect of a range of plant-derived insecticides on the behaviour of larvae of the black blow fly Phormia regina (Meigen). Azadirachtin (100 and 10 ppm), pyrethrum extract (10 ppm) and the naphthoquinone BTG 505 (1000 ppm) acted as deterrents for P. regina larvae.

Influence of a short exposure to teflubenzuron residues on the predation of thrips by Iphiseius degenerans (Acari: Phytoseiidae) and Orius laevigatus (Hemiptera: Anthocoridae).

A short duration (24h) leaf-disc bioassay was used to determine the effects of teflubenzuron residues on the predation levels of two predators, Iphiseius degenerans (Berlese) and Orius laevigatus (Fieber), foraging on nymphs of two species of thrips, Frankliniella occidentalis (Pergande) and Heliothrips haemorrhoidalis (Bouche), on a range of different species of plant. Teflubenzuron did cause thrips mortality during the 24-h bioassay; it was more active against H haemorrhoidalis than F occidentalis. Teflubenzuron did not cause significant mortality to either species of predator, although on some plants the effectiveness of both predators was reduced in the presence of teflubenzuron.

Relationship between nutritional composition of plant species and infestation levels of thrips.

Levels of soluble protein and carbohydrate (raffinose, sucrose, glucose, and fructose) in leaves from a selection of plant species were measured to determine if a relationship existed between these nutrients and infestation by Frankliniella occidentalis and Heliothrips haemorrhoidalis. Most species of host plant examined contained a higher proportion of protein than carbohydrates, and overall, leaves from species of plants that supported populations of thrips had greater levels of protein than leaves from nonhost species. New leaves and flowers that supported F.

Toxicity and behavioural effects of diet-borne alkaloids on larvae of the black blowfly, Phormia regina.

Larvae of the black blowfly, Phormia regina (Meigen) (Diptera: Calliphoridae) were exposed for 24 h to artificial diets that contained one of the following alkaloids: arecoline, caffeine, nicotine, quinine, sparteine or strychnine at either 1000 or 100 p.p.m.

Influence of odor from wood-decaying fungi on host selection behavior of deathwatch beetle, Xestobium rufovillosum.

Adult females of Xestobium rufovillosum de Geer demonstrated anemotactic orientation when exposed to an odor plume containing volatiles generated by wood-decaying fungi (Coriolus versicolor, Donkioporia expansa) and decayed oak wood (Quercus petraea, Quercus robur). They did not orient towards undecayed oak wood, beech (Fagus sylvatica), or pine wood (Pinus sylvestris). Although all insects tested showed anemotactic orientation, responses were nonlinear with respect to insect age.

Responses of Spodoptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves.

Thirteen plants growing in Tunisia were tested against Spodoptera littoralis larvae. From the acetone extract of Ajuga pseudoiva leaves, showing interesting antifeedant activity, three new (1-3) and two known (4-5) active clerodane diterpenoids were isolated following a bioassay-guided chromatography.

Bioactive sesquiterpenes from Santolina rosmarinifolia subsp. Canescens. A conformational analysis of the germacrane ring.

The hexane extract of aerial parts of Santolina rosmarinifolia subsp. canescens afforded eight new sesquiterpenes in addition to known compounds. Their structures were determined by spectroscopic methods and chemical transformations.

From a phagostimulant natural product to semisynthetic antifeedants against Spodoptera littoralis larvae: chemical transformations of the neoclerodane diterpenoid scutegalin B.

Scutegalin B (4), a natural neoclerodane diterpenoid possessing phagostimulant activity against larvae of the lepidopteran Spodoptera littoralis, has been subjected to a series of chemical transformations obtaining several derivatives. The activity of some of these changes to antifeedant (10, 12, 16, and 17), although other derivatives are inactive (6, 7, and 15) or maintain phagostimulant activity (8 and 9) of the starting material (4). The most potent antifeedant was 16, which possesses 16,15-lactone and a (19S)-19, 2alpha-hemiacetal groups instead of the 16,15-lactol and (19R)-(19-O-tigloyl)19,2alpha-hemiacetal of the phagostimulant precursor 4.

Developmental inhibition ofSpodoptera litura (Fab.) larvae by a novel caffeoylquinic acid from the wild groundnut,Arachis paraguariensis (Chod et Hassl.).

A novel compound, 1-caffeoyl-4-deoxyquinic acid (1-CdQA) has been identified along with 3-caffeoylquinic acid (3-CQA) and 5-caffeoylquinic acid (5-CQA) (syn. chlorogenic acid) in the foliage ofArachis paraguariensis, a wild species of groundnut that is highly resistant to attack by the larvae ofSpodoptera litura. When neonate larvae were fed on diets treated with 3-CQA or 1-CdQA, their development was severely inhibited compared to larvae on untreated diets, and the effects were similar in nature and magnitude to those observed for larvae feeding on diets treated with 5-CQA, rutin, and quercetin.

Variation in chemosensitivity and the control of dietary selection behaviour in the locust.

Investigations into the behavioural and underlying physiological mechanisms of dietary selection are presented for the locust, Locusta migratoria. Locusts were fed for 4, 8 or 12 h on one of four chemically defined artificial diets: diet PC, which was nutritionally complete; diet P, containing no digestible carbohydrate; diet C, containing no protein; and diet O, which lacked both protein and digestible carbohydrate. Following this pretreatment, the locusts were provided with both the P and the C diet in a choice test.

Behavioral and electrophysiological study of antifeedant mechanisms associated with polyhydroxy alkaloids.

Eleven polyhydroxy alkaloids of plant origin were tested for anti-feedant effects against larvae of the lepidopteransSpodoptera littoralis, Spodoptera frugiperda, Heliothis virescens, andHelicoverpa armigera. Data from behavioral and electrophysiological investigations were correlated to reveal information on the mode of action of the antifeedants. The pyrrolidine DMDP was an effective antifeedant for all four species, whereas the piperidines fagomine and XZ-1 and the pyrrolizidine alexine were all ineffective as antifeedants.

Insect antifeedant activity associated with compounds isolated from species ofLonchocarpus andTephrosia.

The antifeedant activity of a series of 21 chalcones, flavanes, and flavanones isolated from the generaLonchocarpus andTephrosia (Leguminosae) was assessed by behavioral and electrophysiological bioassays against larvae ofSpodoptera littoralis andS. exempta. The antifeedant activity is related to the molecular structure of the compounds, and possible modes of interaction with the insect taste receptors are discussed.

Insect antifeedant properties of anthranoids from the genusVismia.

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.

The ultrastructure of an olfactory sensillum on the maxillary palps of locusta migratoria (L.).

The olfactory sensilla on the maxillary palp tip of Locusta migratoria (L.) resemble the surrounding contact chemoreceptors in general morphology. The perforated peg has a thicker wall than is commonly found in olfactory sensilla.

The significance of palpation by the maxillary palps of Locusta migratoria (L): an electrophysiological and behavioural study.

Palpation increases the amount of sensory input reaching the central nervous system compared with that obtained from sustained contact but that increase is not essential to allow discrimination. During a meal on favoured food, phagostimulatory input from the palps is not needed to drive feeding. When less favoured food is taken, phagostimulatory input from the palps may enhance feeding.

Behavioural and electrophysiological studies of taste discrimination by the maxillary palps of larvae of Locusta migratoria (L.).

1. Behavioural studies show that larvae of Locusta migratoria (L.) can discriminate between certain simple chemicals and between chemicals obtained from plant sources.