Critical links between biodiversity and health in wild bee conservation.

Wild bee populations are declining due to human activities, such as land use change, which strongly affect the composition and diversity of available plants and food sources. The chemical composition of food (i.e., nutrition) in turn determines the health, resilience, and fitness of bees. For pollinators, however, the term 'health' is recent and is subject to debate, as is the interaction between nutrition and wild bee health. We define bee health as a multidimensional concept in a novel integrative framework linking bee biological traits (physiology, stoichiometry, and disease) and environmental factors (floral diversity and nutritional landscapes). Linking information on tolerated nutritional niches and health in different bee species will allow us to better predict their distribution and responses to environmental change, and thus support wild pollinator conservation.

Scope for non-crop plants to promote conservation biological control of crop pests and serve as sources of botanical insecticides.

Besides providing food and shelter to natural enemies of crop pests, plants used in conservation biological control interventions potentially provide additional ecosystem services including providing botanical insecticides. Here we concurrently tested the strength of these two services from six non-crop plants in managing cabbage pests in Ghana over three successive field seasons. Crop margin plantings of Ageratum conyzoides, Tridax procumbens, Crotalaria juncea, Cymbopogon citratus, Lantana camara and Talinum triangulare were compared with a bare earth control in a three-way split plot design such that the crop in each plot was sprayed with either a 10% (w/v) aqueous extract from the border plant species, a negative control (water) and a positive control (emamectin benzoate 'Attack' insecticide). Pests were significantly less numerous in all unsprayed treatments with non-crop plant margins and in corresponding sprayed treatments (with botanical or synthetic insecticide positive control) while treatments with bare earth margin or sprayed with water (negative controls) had the highest pest densities. Numbers of predators were significantly depressed by synthetic insecticide but higher in other treatments whether unsprayed or sprayed with botanical insecticide. We conclude that some plant species have utility in both conservation biological control and as source of botanical insecticides that are relatively benign to natural enemies. In this crop system, however, the additional cost associated with using botanical insecticides was not justified by greater levels of pest suppression than achieved from border plants alone.

Responses to colour and host odour cues in three cereal pest species, in the context of ecology and control.

Many insects show a greater attraction to multimodal cues, e.g. odour and colour combined, than to either cue alone. Despite the potential to apply the knowledge to improve control strategies, studies of multiple stimuli have not been undertaken for stored product pest insects. We tested orientation towards a food odour (crushed white maize) in combination with a colour cue (coloured paper with different surface spectral reflectance properties) in three storage pest beetle species, using motion tracking to monitor their behaviour. While the maize weevil, Sitophilus zeamais (Motsch.), showed attraction to both odour and colour stimuli, particularly to both cues in combination, this was not observed in the bostrichid pests Rhyzopertha dominica (F.) (lesser grain borer) or Prostephanus truncatus (Horn) (larger grain borer). The yellow stimulus was particularly attractive to S. zeamais, and control experiments showed that this was neither a result of the insects moving towards darker-coloured areas of the arena, nor their being repelled by optical brighteners in white paper. Visual stimuli may play a role in location of host material by S. zeamais, and can be used to inform trap design for the control or monitoring of maize weevils. The lack of visual responses by the two grain borers is likely to relate to their different host-seeking behaviours and ecological background, which should be taken into account when devising control methods.

Caffeine in floral nectar enhances a pollinator's memory of reward.

Plant defense compounds occur in floral nectar, but their ecological role is not well understood. We provide evidence that plant compounds pharmacologically alter pollinator behavior by enhancing their memory of reward. Honeybees rewarded with caffeine, which occurs naturally in nectar of Coffea and Citrus species, were three times as likely to remember a learned floral scent as were honeybees rewarded with sucrose alone. Caffeine potentiated responses of mushroom body neurons involved in olfactory learning and memory by acting as an adenosine receptor antagonist. Caffeine concentrations in nectar did not exceed the bees' bitter taste threshold, implying that pollinators impose selection for nectar that is pharmacologically active but not repellent. By using a drug to enhance memories of reward, plants secure pollinator fidelity and improve reproductive success.

The effect of cicerfuran, an arylbenzofuran from Cicer bijugum, and related benzofurans and stilbenes on Leishmania aethiopica, L. tropica and L. major.

The effect of 3 arylbenzofurans and 7 stilbenes on the growth of Leishmania parasites and human monocytes was evaluated. Promastigotes from cultures of L. aethiopica, L. major and L. tropica were tested in the exponential phase of growth. All compounds were active at concentrations of 100 microg/mL within 6 hours. The 2-hydroxylstibene showed activity at a concentration < 1 microg/mL, with an LD (50) of 3 - 5 microg/mL after 48 hours of incubation. The most active compounds: cicerfuran, 2-hydroxy-2'-methyl-4',5'-methylenedioxystilbene, 2-hydroxy-2'-methoxy-4',5'-methylenedioxystilbene and 2-hydroxystilbene had even stronger activity against the temperature-induced amastigotes of L. aethiopica, with the latter having the highest relative potency against all three species. Leishmanicidal activity seemed to be associated with the level of oxygen substitution in each compound. The ratio between leishmanicidal activity on promastigotes and toxicity to human cells suggested that the compounds could be considered as leishmanicidal drug leads.

Identification of methyl salicylate as the principal volatile component in the methanol extract of root bark of Securidaca longepedunculata Fers.

Securidaca longepedunculata Fers (Polygalaceae) is commonly used as a medicine in many parts of Africa and shows promise for protecting stored grain against insect pests. Analysis of a methanol extract of the root bark by gas chromatography linked to mass spectrometry (GC/MS) showed a major component accounting for over 90% of the volatile material. This was identified as methyl 2-hydroxybenzoate (methyl salicylate) by comparison of the GC retention times and mass spectrum with those of synthetic standards. This conflicts with an earlier report that the major component is methyl 4-hydroxybenzoate. Two minor components had mass spectra characteristic of 2-hydroxybenzoate esters and were identified as methyl 2-hydroxy-6-methoxybenzoate and its benzyl analogue, again conflicting with an earlier report.

Can larvae of the pod-borer, Helicoverpa armigera (Lepidoptera: Noctuidae), select between wild and cultivated pigeonpea Cajanus sp. (Fabaceae)?

Experiments were conducted to observe the feeding and food selection-behaviour of different instars of the pod-borer Helicoverpa armigera (Hübner) in response to choices between the cultivated and a wild species of Cajanus. First and second instars fed upon a cultivated variety of Cajanus cajan in preference to a wild species, C. scarabaeoides and on flowers of C. cajan, rather than pods or leaves of C. cajan. First and second instars preferred pods of C. scarabaeoides with trichomes removed to pods with trichomes present. All instars fed upon pods of C. cajan rather than those of C. scarabaeoides. Solvent extraction of the pod surfaces affected the feeding of larvae, in some instances. They preferred the unextracted pods of C. cajan; the extracted pod of C. scarabaeoides (first and second instars) or the unextracted pod of C. scarabaeoides (fourth and fifth instars). Glass-fibre disc bioassays showed that the methanol, hexane and water extracts from the pod-surface of C. cajan stimulated the feeding of fifth instars. The experiments have shown that characteristics of C. cajan, such as either the compounds present or the type and distribution of trichomes on the plant surfaces, can determine the susceptibility of C. cajan to pod-borer larvae.

The torturous road to democracy--domestic crisis in Nepal.

Largely unnoticed by the outside world, an armed Maoist insurgence has wrested control of areas in 45 of Nepal's 75 administrative regions and has resulted in more than 1700 deaths since 1996.(1) State figures indicate that 1000 of these people were Maoist and about 400 were police-120 of whom died in attacks on police outposts in early April and July of 2001 alone. The remainder were "class enemies" of the "People's War"-ie, members of ruling parties. As public security collapses, the consequences for the Nepalese are random imprisonment, torture, and risk of extrajudiciary execution from both sides. Torture has increased greatly as a consequence of the insurgence, but was already deeply rooted in Nepalese authority and used as a primary approach to solving crime. More than 70% of Nepalese prisoners claim to have been tortured while in custody, and at least 50% claim they signed confessions as a result. INSEC (Informal Sector Service Centre), a human rights organisation, documented 1035 cases of state perpetrated torture in the year 2000,(2) which has been suggested to be a gross underestimate of the true figure. The long-term physical, social, and psychosocial consequences for survivors are often severe. The Centre for Victims of Torture, Nepal, a non-government organisation based in Kathmandu, has been studying the effect of torture on survivors, and has implemented Nepal's only treatment programmes for those brave enough to seek help.

Insect antifeedant activity of three new tetranortriterpenoids from Trichilia pallida.

Three new tetranortriterpenoids, methyl 6-hydroxy-11 beta-acetoxy-12 alpha-(2-methylpropanoyloxy)-3,7-dioxo-14 beta,15 beta-epoxy-1,5-meliacadien-29-oate (3), methyl 6,11 beta-dihydroxy-12 alpha-(2-methylpropanoyloxy)-3,7-dioxo-14 beta,15 beta-epoxy-1,5-meliacadien-29-oate (4), and methyl 6-hydroxy-11 beta-acetoxy-12 alpha-(2-methylbutanoyloxy)-3,7-dioxo-14 beta,15 beta-epoxy-1,5-meliacadien-29-oate (5), have been isolated from the roots of Trichilia pallida. The related compounds hirtin (1) and deacetylhirtin (2) were also obtained. Compound 4 had the greatest antifeedant activity of 1-5 when tested against larvae of four species of Lepidoptera.

Effects of isoflavonoids from Cicer on larvae of Heliocoverpa armigera.

Four recently identified isoflavonoids, isolated from wild relatives of chickpea, Cicer arietinum, were shown to deter larval feeding by Heliocoverpa armigera at 100 ppm, judaicin and maackiain retained their antifeedant activity at 50 ppm and 10 ppm, respectively. The isoflavonoids were tested in combinations and with chlorogenic acid; the combinations containing judaicin and maackiain were most active, and chlorogenic acid enhanced the antifeedant activity of all four isoflavonoids. H. armigera was the only one of four noctuids to be deterred by all four isoflavonoids. Spodoptera littoralis was deterred by judaicin alone and S. frugiperda by maackiain alone. Heliothis virescens and S. exigua were not deterred from feeding by any of the isoflavonoids. When incorporated into a diet, isoflavonoids decreased the weight gain of early stadia larvae of H. armigera more than they did later stadia, and maackiain and judaicin were most potent. We conclude that the isoflavonoids. especially maackiain and judaicin, could play a role in decreasing the susceptibility of Cicer to attack by H. armigera.

Toxicity following accidental ingestion of Aconitum containing Chinese remedy.

Various species of Aconitum are commonly used in traditional Chinese medicine. These plants are known to contain highly potent cardiotoxins. A 22 year old Chinese male accidentally ingested a herbal liniment prepared from Aconitum with near fatal results. His ventricular tachyarrhythmias responded to standard treatment including the use of i.v. magnesium.

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. The effects of all the compounds were dose related, and their optimal concentration was approximately 3 mM, which corresponds to the total foliar concentration of both caffeoylquinic acids and quercetin diglycosides inA. paraguariensis. After 24 h, the development of third stadium larvae feeding on diets treated with 5-CQA, rutin and 1-CdQA was promoted compared to larvae on control diets, but after 96 hr larvae feeding on treated diets had gained significantly less weight than those on the control diets. 1-CdQA, 3-CQA, and quercetin dyglycosides (previously identified in the foliage ofA. paraguariensis) are considered to be valuable components in resistance of groundnuts toS. litura and may provide useful genetic markers in future breeding for resistance to this pest.