Search

The "River Disease” (RD), a disorder impacting honeybee colonies located closed to waterways with abundant riparian vegetation (including Sebastiania schottiana, Euphorbiaceae), kills newly hatched larvae. Forager bees from RD-affected colonies collect honeydew excretions from Epormenis cestri (Hemiptera: Flatidae), a planthopper feeding on trees of S. schottiana. First-instar honeybee larvae fed with this honeydew died. Thus, we postulated that the nectars of RD-affected colonies had a natural toxin coming from either E. cestri or S. schottiana. An untargeted metabolomics characterization of fresh nectars extracts from colonies with and without RD allowed to pinpoint xanthoxylin as one of the chemicals present in higher amounts in nectar from RD-affected colonies than in nectars from healthy colonies. Besides, xanthoxylin was also found in the aerial parts of S. schottiana and in the honeydew excreted by E. cestri feeding on this tree. A larva feeding assay where xanthoxylin-enriched diets were offered to 1st instar larvae showed that larvae died in the same proportion as larvae did when offered enriched diets with nectars from RD-colonies. These findings demonstrate that a xenobiotic can mimic the RD syndrome in honeybee larvae and provide evidence of an interspecific flow of xanthoxylin among three trophic levels. Further, our results give information that can be considered when implementing measures to control this honeybee disease.

The “River Disease” (RD), a disorder impacting honeybee colonies located close to waterways with abundant riparian vegetation (including Sebastiania schottiana, Euphorbiaceae), kills newly hatched larvae. Forager bees from RD-affected colonies collect honeydew excretions from Epormenis cestri (Hemiptera: Flatidae), a planthopper feeding on trees of S. schottiana. First-instar honeybee larvae fed with this honeydew died. Thus, we postulated that the nectars of RD-affected colonies had a natural toxin coming from either E. cestri or S. schottiana. An untargeted metabolomics characterization of fresh nectars extracts from colonies with and without RD allowed to pinpoint xanthoxylin as one of the chemicals present in higher amounts in nectar from RD-affected colonies than in nectars from healthy colonies. Besides, xanthoxylin was also found in the aerial parts of S. schottiana and the honeydew excreted by E. cestri feeding on this tree. A larva feeding assay where xanthoxylin-enriched diets were offered to 1st instar larvae showed that larvae died in the same proportion as larvae did when offered enriched diets with nectars from RD-colonies. These findings demonstrate that a xenobiotic can mimic the RD syndrome in honeybee larvae and provide evidence of an interspecific flow of xanthoxylin among three trophic levels. Further, our results give information that can be considered when implementing measures to control this honeybee disease.

The Asian citrus psyllid, Diaphorina citri, is currently the most important pest of citrus worldwide because it vectors ‘Candidatus Liberibacter’ spp., the etiological agents of lethal Huanglongbing (HLB). Reduction of D. citri populations is a key component of HLB management. Identifying potential D. citri attractants, such as volatiles, could be useful for behavioral management of this insect. This could, for instance, enhance catches of adults on monitoring traps. The overall aim of this study was to investigate the response of D. citri to volatiles characteristic of preferred citrus hosts. An ancillary objective was to formulate a synthetic blend of volatiles based on preferred host odors that could enhance monitoring traps. Volatile collections of two preferred citrus species, Duncan grapefruit (Citrus paradise) and sweet orange (Citrus sinensis), were performed in aeration chambers and analyzed by gas chromatography-mass spectrometry. Based on the grapefruit volatile profile, a synthetic blend consisting in d-limonene (0.62 mg), methyl N-methylanthranilate (0.19 mg), β-ocimene (0.11 mg), β-elemene (0.02 mg), and β-caryophyllene (0.02 mg) was prepared in 9.9 mL of dichloromethane and evaluated for attractiveness, as well as the individual compounds, and compared with a positive control of natural volatiles collected from Citrus sinensis. Behavior of D. citri adults was evaluated in two-choice behavioral assays comparing response to lures with different combinations and dosages of the volatiles deployed on yellow sticky traps. Individually, neither d-limonene nor methyl N-methylanthranilate affected behavior of D. citri. However, these volatiles increased catches of D. citri, as compared with solvent control, when presented as components of the synthetic grapefruit blend, as did the natural citrus odor positive control. Importantly, catch of D. citri appeared to vary with the release rate of the identified grapefruit volatile blend, which was attractive at a 0.1 mg loading dosage, but repellent at a dosage only 1 log step higher.

The bronze bug, Thaumastocoris peregrinus Carpintero & Dellape (Heteroptera: Thaumastocoridae), is an exotic emerging pest in Eucalyptus commercial forests in South America, Africa, and southern Europe. Information on the chemical communication system and reproductive ecology of this insect is scant, and it may be relevant for designing management strategies for eucalypt plantations. Males emit large amounts of 3-methyl-2-butenyl butyrate, which attracts conspecific adult males but not females. To learn more about the biological function of this putative male-produced pheromone, we quantified this compound in volatile emissions collected from males, females, and couples, in three 4-h collecting periods during the morning, afternoon, and night of a single 24-h cycle. Our results showed that virgin males emit 3-methyl-2-butenyl butyrate in a diel time pattern, with an almost sevenfold difference between the afternoon emission peak compared to morning or night hours. In addition, we show that in the presence of females, males emit the compound in the same amounts throughout the photocycle. While a definite function cannot yet be attributed to the emission of 3-methyl-2-butenyl butyrate by T. peregrinus males, our findings point to an intraspecific function, possibly one related to male-male competition.

The bronze bug, Thaumastocoris peregrinus Carpintero & Dellape (Heteroptera: Thaumastocoridae), is an exotic emerging pest in Eucalyptus commercial forests in South America, Africa and southern Europe. Information on the chemical communication system and reproductive ecology of this insect is scant, and it may be relevant for designing management strategies for eucalypt plantations. Adults and nymphs usually aggregate in the field, possibly by means of chemical signals. Males emit large amounts of 3-methyl-2-butenyl butyrate, which attracts conspecific adult males but not females. The ecological role of this putative male aggregation pheromone remains unknown. Here, we report olfactometer bioassays showing that late-instar male nymphs are also attracted to synthetic 3-methyl-2-butenyl butyrate and to adult male volatile extracts, which contain this compound as the major component. As previously shown for adult females, nymphs that moulted into females were not attracted to either volatile stimulus. The intra-gender attraction of nymphs and adults may be related to the exploitation of food resources, or as a reproductive strategy for newly emerged males. Further studies on the reproductive behaviour and mating system of T. peregrinus will contribute to understanding the ecological significance of male-male, adult-nymph attraction, as well as the practical applications that may result from these findings.

Diversos parásitos y patógenos afectan la productividad y la supervivencia de las abejas melíferas. Los metabolitos secundarios de las plantas son tratamientos alternativos potenciales, sin embargo, su efecto ha sido poco estudiado sobre las enfermedades microsporidianas. Además, hay poca información sobre la toxicidad resultante de la administración oral prolongada de estas sustancias a las abejas. En esta investigación, evaluamos los efectos in vivo de diferentes aceites esenciales y componentes principales (CPs) sobre la supervivencia de abejas y el desarrollo de Nosema ceranae bajo un régimen de ad libitum sin elección. Las sustancias administradas en el jarabe de sacarosa a las abejas recién emergidas a diferentes concentraciones se consumieron con avidez y causaron diferentes resultados de supervivencia. No obstante, las dosis subletales de sustancias no controlaron el parásito. Diverse parasites and pathogens affect productivity and survival of honey bees. Plant secondary metabolites are poten- tial alternative treatments, however, their effect has been little studied on microsporidian diseases. Furthermore, there is poor information about the toxicity resulting from prolonged oral administration of these substances to bees. In this research, we evaluated in vivo effects of different essential oils and main components (MCs) on bee survival and Nosema ceranae development under an ad libitum non-choice regimen. Substances administered on sucrose syrup to newly emerged bees at different concentrations were avidly consumed and caused different survival performances. Neverthe- less, sublethal doses of substances did not control the parasite. Fil: Porrini, Martín Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Garrido, Paula Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Gende, Liesel Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Rossini, Cármen. Universidad de la República; Uruguay Fil: Hermida, Laura Graciela. Instituto Nacional de Tecnología Industrial; Argentina Fil: Marcangeli, Jorge Augusto. Universidad Nacional de Mar del Plata; Argentina Fil: Eguaras, Martin Javier. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina

When developing new products to be used in honeybee colonies, further than acute toxicity, it is imperative to perform an assessment of risks, including various sublethal effects. The long-term sublethal effects of xenobiotics on honeybees, more specifically of acaricides used in honeybee hives, have been scarcely studied, particularly so in the case of essential oils and their components. In this work, chronic effects of the ingestion of Eupatorium buniifolium (Asteraceae) essential oil were studied on nurse honeybees using laboratory assays. Survival, food consumption, and the effect on the composition of cuticular hydrocarbons (CHC) were assessed. CHC were chosen due to their key role as pheromones involved in honeybee social recognition. While food consumption and survival were not affected by the consumption of the essential oil, CHC amounts and profiles showed dose-dependent changes. All groups of CHC (linear and branched alkanes, alkenes and alkadienes) were altered when honeybees were fed with the highest essential oil dose tested (6000 ppm). The compounds that significantly varied include n-docosane, n-tricosane, n-tetracosane, ntriacontane, n-tritriacontane, 9-tricosene, 7-pentacosene, 9-pentacosene, 9-heptacosene, tritriacontene, pentacosadiene, hentriacontadiene, tritriacontadiene and all methyl alkanes. All of them but pentacosadiene were up-regulated. On the other hand, CHC profiles were similar in healthy and Nosema-infected honeybees when diets included the essential oil at 300 and 3000 ppm. Our results show that the ingestion of an essential oil can impact CHC and that the effect is dose-dependent. Changes in CHC could affect the signaling process mediated by these pheromonal compounds. To our knowledge this is the first report of changes in honeybee cuticular hydrocarbons as a result of essential oil ingestion., Instituto de Investigaciones Bioquímicas de La Plata

Persicaria maculosa (Polygonaceae) (known as lady&rsquo, s thumb) is an annual morphologically variable weed that is widely distributed in Chile. The purpose of this study was to investigate the antifeedant potential of methanolic (MeOH), ethanolic (EtOH), and dichloromethane (DCM) extracts from the aerial parts of this plant collected in the Valpara&iacute, so and Curic&oacute, provinces (Chile) and relate this activity to the antioxidant capacity and the presence of phenolic compounds in the extracts. A phenolic profile based on HPLC-ESI-MS/MS allowed the identification of 26 phenolic compounds, most of them glycosyl derivatives of isorhamnetin, quercetin, and kaempferol. In addition, the total phenolic content (TP), total flavonoids (TF), and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion scavenging (O2&minus, ), ferric-reducing antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) of the extracts are reported. The antifeedant potentials of the plant extracts were tested against Epilachna paenulata, Pseudaletia adultera, Macrosiphum euphorbiae, and Diaphorina citri insects for the first time. The activity against the aphid M. euphorbiae was significant for the DCM extracts of plants from Valpara&iacute, (settling % = 23% &plusmn, 4% and 23% &plusmn, 5%, respectively). The antifeedant activities against the beetle E. paenulata and the lepidoptera P. adultera were significant for Valpara&iacute, so extracts, especially when tested against E. Paenulata (IFP = 1.0 &plusmn, 0.0). Finally, the MeOH and EtOH extracts from Valpara&iacute, so plants reduced the diet consumption of the psilid D. citri (p &lt, 0.05). The results showed that P. maculosa is a good source of flavonoids with some antioxidant capacities and has potential interest as botanical eco-friendly alternative with deterrent activity.

Tomato (Solanum lycopersicum L.) crops are affected by a diversity of pests. Among these pests, the whitefly Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) and the leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) cause large yield losses. The effects from these insects are often minimized by applying synthetic pesticides, although these have many drawback. To characterize novel tools for insect control, essential oils from two Asteraceae (Artemisia absinthium and Eupatorium buniifolium) were studied for their potential toxicity to beneficial insects [honey bees (Apis mellifera L.)] and phytotoxic effects against tomato seeds and vegetative parts. Our results show that seed germination was affected at application rates needed to control the leafminer T. absoluta but not at rates needed to control the whitefly T. vaporariorum. The same trend was found for honeybee toxicity: the use of these essential oils at the amounts needed to control T. vaporariorum would be not acutely toxic for bees. Finally, an experimental greenhouse trial showed that the application of the essential oil from E. buniifolium at 3% on whitefly-infested plants can cause whitefly adult mortality without affecting the crop yield. Fil: Umpiérrez, María Laura. Universidad de la República. Facultad de Química. Departamento de Química Orgánica. Laboratorio de Ecología Química; Uruguay Fil: Paullier, Jorge. Instituto Nacional de Investigación Agropecuaria. Sección Protección Vegetal; Uruguay Fil: Porrini, Martín Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina Fil: Garrido, Paula Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina Fil: Santos, Estela. Universidad de la República. Facultad de Ciencias; Uruguay Fil: Rossini, Carmen. Universidad de la República. Facultad de Química. Departamento de Química Orgánica. Laboratorio de Ecología Química; Uruguay

Various cutaneous glands have been identified as sources of chemical signals that mediate many social interactions in deer. The pampas deer, a species considered near threatened, inhabits grasslands of South America. In this work, the chemical compositions from preorbital, tarsal, and digital gland secretions of semi-captive males were characterized by gas chromatography–mass spectrometry. The composition of these secretions showed a great complexity, with 143 compounds detected. Hierarchical cluster and principal component analyses show no relation to age or secretion type. Five compound classes (esters, fatty alcohols, lactones, sterols, and sulphuretted) differed with glands. The chemical complexity of the secretions, the individual differences in the whole compounds composition, and the absence of clustering by age lead to the hypothesis that these secretions may encode at once for individual information and for social status information. Varias glándulas cutáneas han sido identificadas como productoras de señales químicas que median interacciones sociales en losciervos. El venado de las pampas es una especie considerada casi amenazada que habita los pastizales de Sudamérica. En este trabajo se caracterizó la composición química de las secreciones de las glándulas preorbital, tarsal e interdigital de machos por cromatografía de gases-espectrometría de masas. Estas secreciones mostraron una gran complejidad en su composición, con 143 compuestos detectados. No se observó ninguna agrupación de compuestos relacionada con la edad o el tipo de secreción. Cinco clases de compuestos (ésteres, alcoholes grasos, lactonas, esteroles, y compuestos azufrados) difirieron de acuerdo al origen glandular. La complejidad química de las secreciones, las diferencias individuales en dicha composición, y la ausencia de agrupamiento por edad, llevan a postular la hipótesis de que estas secreciones pueden codificar a la vez tanto información individual como del estado social.

Botanical biopesticides constitute an important tool for Integrated Pest Management practices. Uruguay has a great potential for developing botanical biopesticides from its abundant native flora. Dodonaea viscosa Jacq. is a native Sapindaceae that in preliminary studies was shown to possess a potential deterrent activity against insect models. In this work, ethanolic extracts of the leaves of this species were studied. Bioguided fractionation and supercritical fluid extraction led to the isolation of active compounds. For that purpose four insect models were used: Epilachna paenulata, Spodoptera littoralis, Myzus persicae, and Rhopalosiphum padi, which are pests of crops of economic importance. Lupeol, stigmasterol, stigmast-7-en-3-ol, and a labdane diterpene were isolated and showed differential activity against the models., The work developed in Spain was supported by Programa de Desarrollo de las Ciencias Básicas (PEDECIBA), Comisión Sectorial de Investigación Científica (CSIC), and Organization for the Prohibition of Chemical Weapons (OPCW).

The phytochemical study of Uruguayan specimens of Allophylus edulis (Sapindaceae) yielded the isolation of various natural products being some of them reported for the first time in this species. Although most of them are ubiquitous in the plant kingdom, some revealed in this study to have anti insect properties. Two sesquiterpenes (6,7-Epoxicaryophyllene and spathulenol), two phytosterols (sitosterone and sitosterol), a pentacyclic triterpene (lupeol) and a clerodane diterpene were isolated. 6,7-Epoxycaryophyllene, lupeol and sitosterol showed to be deterrent against the aphid Myzus persicae and the coleopteran Epilachna paenulata. Moreover, the crude ethanolic extract of twigs of A. edulis showed to be deterrent against both insect species being some of its fractions also active against another aphid, Rhopalosiphum padi. Various active compounds against different insect models have been isolated from the twigs extract of A. edulis. The results evidenced synergic as well as antagonistic effects in the mixture, summed to differential activity against the insects, a desirable attribute when developing botanical pesticides.

Cucurbitacins are secondary metabolites that mediate insect plant interactions not only as allomones against generalists but also as kairomones for specialist herbivores. This study was undertaken to identify the potential of cucurbitacin derivatives as insect antifeedant agents. The antifeedant capacity against a Cucurbitaceae specialist [Epilachna paenulata (Coleoptera: Coccinellidae)] and a polyphagous insect [Pseudaletia adultera (Lepidoptera: Noctuidae)] was evaluated in preference tests in which the insects were given a choice between food plants either treated with the cucurbitacin derivatives or treated with the solvent. The activity was found not to be related to the basic cucurbitacin skeleton, as only 15 of the 28 tested cucurbitacin derivatives were active. Only one of the tested compounds was phagostimulant to the specialist insect (the hemissuccinate of 16-oxo-dihydrocucurbitacin B derivative), while all other active derivatives were deterrent against one of the insects (13 compounds) or both of them (3 compounds). Changes in ring A of the cucurbitacins, as well as in the side chain, modified the activity. As a general trend, when chemical modifications of the basic structure produced a change in activity, the response was opposite in both insects used as biodetectors, indicating that a selective variation in the activity may be achieved by chemical modifications of the cucurbitacin skeleton. Fil: Lang, Karen L.. Universidade Federal de Santa Catarina; Brasil Fil: Deagosto, Emilio. Universidad de la República; Uruguay Fil: Zimmermann, Lara Almida. Universidade Federal de Santa Catarina; Brasil Fil: Machado, Vanessa Rocha. Universidade Federal de Santa Catarina; Brasil Fil: Bernardes, Lílian Sibelle Campos. Universidade Federal de Santa Catarina; Brasil Fil: Schenkel, Eloir P.. Universidade Federal de Santa Catarina; Brasil Fil: Duran, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Palermo, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina Fil: Rossini, Carmen. Universidad de la República; Uruguay

Secondary metabolites from plants have been the source of various natural products with anti-insect properties; having some of them already reached the market. In recent years, the drawbacks related to the use of synthetic pesticides have triggered the need to find alternatives and brought about revitalization on bioprospecting programs. In that direction, this work presents the results of a study on a South American native species. The methanolic leaf extract of Clytostoma callistegioides (Bignoniaceae), was hydrolyzed with HCl, and sequentially subjected to Sephadex LH20 and HPLC procedures. Three flavones, not previously obtained from this species, were identified by NMR and UV spectra: 4′-Hydroxywogonin, Acacetin and Galangustin. Two important agricultural pests, Myzus persicae and Rhopalosiphum padi (Hemiptera: Aphididae), were studied in their reluctance to settling on leaf treated with these flavonoids, and the results are here reported in terms of a preference index (PI), calculated as PI = [(%C − %T)/(%C + %T)]; where %C and %T are the percentages of aphids settled on the treated and the control leaf pieces, respectively. While 4′-Hydroxywogonin did not exhibit significant activity against neither of the aphids, Acacetin was active only against R. padi (PI = 0.3 ± 0.1). Further, Galangustin exhibited a better deterrence activity on the settling of both aphids (PI = 0.4 ± 0.1 and 0.8 ± 0.1 for M. persicae and R. padi respectively).

Crocidosema (= Epinotia) aporema (Walsingham) (Lepidoptera: Tortricidae) is a bud borer that feeds on soybean and forage legumes. Its economic importance is restricted to South America, where it can alternate throughout the year between forage and grain legumes. The sex pheromone of C. aporema females is composed of a 15:1 mixture of (7Z,9Z)-dodeca-7,9-dien-1-ol and (7Z,9Z)-dodeca-7,9-dienyl acetate. Aiming at the development of a monitoring tool, it was synthesized both components of the pheromone and evaluated male captures in pheromone traps baited with different blends of synthetic pheromone, in an experimental soybean field in Uruguay. The conjugated dienes were obtained from 2-pentyn-1-ol and 1,7-heptanediol, by oxidation of the former, Wittig coupling and Zn-catalyzed reduction of the triple bond. The 1:1 mixture was the most efficient in capturing males. The pheromone traps were attractive for up to 40 days, even with small septum loads (0.1 mg) and low population levels.

Nowadays, new strategies for pest and disease control to be used in rotation with or replacement of conventional pesticides are required. Essential oils (EOs), as botanical pesticides, provide a potential resource to develop more environmentally friendly and less toxic means of control to be applied in different produces. Tomato crop is affected by many insects and fungal diseases, among which, the insects Trialeurodes vaporariorum and Tuta absoluta, and the fungi Alternaria spp. and Botrytis cinerea are of great incidence. In this work two EOs from Uruguayan specimens of the local species Eupatorium buniifolium and the world-wide distributed Artemisia absinthium (Asteraceae) were characterized in their chemical composition and insecticidal and antifungal activities. We found that the EO from local A. absinthium is rich in oxygenated monoterpenes and belongs to the thujone chemotype (β-Thujone abundance is 56 ± 2 %, and α-Thujone, 1.67 ± 0.07 %). On the other hand, monoterpene hydrocarbons (α-Pinene, 22 ± 2 %) and sesquiterpene hydrocarbons [(E)-β-Guaiene, 10 ± 1 %] are the most abundant components of E. buniifolium EO. Eventhough both EOs chemically differ, they exhibit insecticidal and antifungal activity not only by direct contact but also by contact with their vapors against the tested organisms. These results may indicate that these EOs could be raw material to develop control agents to manage some of the main pests and fungal diseases of tomato crops with only one kind of treatment.

Members of the family Bignoniaceae are mostly found in tropical and neo-tropical regions in America, Asia and Africa, although some of them are cultivated in other regions as ornamentals. Species belonging to this family have been extensively studied in regard to their pharmacological properties (as extracts and isolated compounds). The aim of this review is to summarize the reported scientific evidence about the chemical properties as well as that of the extracts and isolated compounds from species of this family, focusing mainly in insect-plant interactions. As it is known, this family is recognized for the presence of iridoids which are markers of oviposition and feeding preference to species which have became specialist feeders. Some herbivore species have also evolved to the point of been able to sequester iridoids and use them as defenses against their predators. However, iridoids also exhibit anti-insect properties, and therefore they may be good lead molecules to develop botanical pesticides. Other secondary metabolites, such as quinones, and whole extracts have also shown potential as anti-insect agents.

Beekeeping has always been vulnerable to various sanitary drawbacks. The mite Varroa destructor (Mesostigmata: Varroidae), an obligated ectoparasite of honeybees, has been in recent times one of the major problems leading not only to economical losses but also to ecological problems related to the role of honeybees as the most important pollinators on Earth. Varroatosis has been treated by methods that include special practices of beekeeping, physical removal, and the use of synthetic acaricides. None of these methods have, however, rendered complete protection, and there is clear evidence for the evolution of resistance to conventional acaricides. Consequently, the need for alternative control means has prompted the onset of several prospecting programs on botanicals with anti-varroa potential. Among these, essential oils appear as good candidates for safer control. In this review, we provide a concise compilation of the information generated in the last years on essential oils with anti-varroa activity. Future developments in this area demand standardization of bioassay protocols (either in the laboratory for primary screening or in hives), a detailed chemical characterization of the essential oils tested, and comprehensive studies on application methods.

The head lice, Pediculus humanus capitis (Phthiraptera:Pediculidae), is an obligate ectoparasite of humans that causes pediculosis capitis, a nuisance for millions of people worldwide, with high prevalence in children. Pediculosis capitis has been treated by methods that include the physical remotion of lice, various domestic treatments and conventional insecticides. None of these methods render complete protection, and there is clear evidence for the evolution of resistance and cross-resistance to conventional insecticides. Non-toxic alternative options are hence needed for head lice treatment and/or prevention, and natural products from plants, especially essential oils (EOs), are good candidates for safer control agents that may provide good anti-lice activity and low levels of evolved resistance. A few EOs have been tested as repellents with promissory results, although often in vitro tests and clinical trials produce contradictory results. A handful of fixed extracts and several EOs and their individual components have also been tested as contact pediculicides or fumigants. The studies have focused mainly on plant families characterized for the production of EOs. While many EOs and individual compounds showed pediculicide activity, comparing results is difficult due to the diverse bioassay methodologies. Studies of anti-lice activity of individual EO components provide the basis for preliminary conclusions of structure–activity relationships, although no clear patterns can yet be drawn. We here attempt to provide a concise compilation of the available information on anti-lice activity of plant extracts and plant-derived compounds, which we hope may be of help for future developments in this area.

The defensive chemistry of the ladybird beetle Epilachna paenulata (Coleoptera: Coccinellidae) was characterized as a mixture of piperidine, homotropane and pyrrolidine alkaloids. Whole body extracts of adult beetles contain four major alkaloids: 1-(6-Methyl-2,3,4,5-tetrahydro-pyridin-2-yl)-propan-2-one; 1-(6-methyl-2-piperidyl)-propan-2-one; 9-aza-1-methyl-bicyclo[3.3.1]nonan-3-one and 1- (2′′- hydroxyethyl)-2-(12′-aminotridecyl)-pyrrolidine. Comparative studies of the defensive chemistry of eggs, larvae, pupae and adults showed both qualitative and quantitative differences in alkaloid composition among the four life stages, and also within adult age. Laboratory predation bioassays with wolf spiders showed that the adults are better protected than the larvae and pupae. Field tests showed the adult alkaloid extract to be deterrent to ants.

Prospection for new sources of botanical pesticides has shown a revival in the last decades due not only to the fast development of resistance among different pests around the world but also by the need to use less eco-toxic products to control etiological agents of different pest-related problems found in agro-production. In this work, extracts from members of the families Simaroubaceae ( Ailanthus altissima , Castela coccinea and Picrasma crenata ) and Picramniaceae ( Alvaradoa subovata and Picramnia sellowii ) were evaluated for their toxicity against the cattle tick and for their antifeedant activity against insects. At the tested doses, none of the extracts exhibited a good toxicity against larvae of the common cattle tick. On the other hand, antifeedant activity was detected in various extracts. Foliage consumption was completely deterred in adults of the specialist Epilachna paenulata in the cases of the C. coccinea leaf and wood extracts and P. crenata wood extract. For larvae of the generalist Spodoptera frugiperda antifeedant effects were also detected, although in a lesser extent. Phytochemical analyses of the extracts showed the presence of alkaloids in P. crenata (including canthin-6-one) and in C. coccinea . Besides, GC/MS analyses of the wood extract from C. coccinea showed the presence of several steroids (ergot 5-en-3-ol-acetate, stigmastan-3,5 diene and stigmasta-3,5dien-7-one). Anthraquinones (emodin and chrysophanol) as well as chlorogenic acid were detected in the cases of A. subovata and P. sellowii extracts. The differences in deterrent activity could not be atributed to differences in the HPLC chemical profiles of the different extracts.

SUMMARY The opilionid Acanthopachylus aculeatus was shown to produce a defensive secretion containing quinones (2,3-dimethyl-1,4-benzoquinone,2,5-dimethyl-1,4-benzoquinone and 2,3,5-trimethyl-1,4-benzoquinone),confirming the findings reported nearly a half century ago in a classic study. The mechanism by which the opilionid puts the secretion to use is described. When disturbed, the animal regurgitates enteric fluid, which it conveys by intercoxal clefts to the anterolateral corners of the carapace, where the two gland openings are situated. It then injects some of its quinonoid secretion into the fluid, and conveys the mixed liquid along the length of its flanks by way of two special channels. Such a discharge mechanism may be widespread among opilionids of the family Gonyleptidae (suborder Laniatores), to which A. aculeatus belongs. In a bioassay based on a scratch reflex in decapitated cockroaches (Periplaneta americana) the liquid effluent of A. aculeatus was shown to be potently irritating. Use of the effluent was demonstrated to protect the opilionid against ants (Formica exsectoides). Wolf spiders (Lycosa ceratiola) were shown to be minimally affected by the effluent (they showed little response when the fluid was added to their mouthparts as they fed on mealworms, their normal laboratory prey), although they proved to be aversive to mere contact with the opiliond itself, and to reject the animal without inducing it to discharge. A. aculeatus may therefore contain distasteful factors besides its glandular products.

Evidence is presented that pyrrolizidine alkaloid acquired by Utetheisa ornatrix (Lepidoptera, Arctiidae) as a larva from Crotalaria foodplants is incorporated in part into the scales of the adult. A single forewing of a male or female moth may contain in the order of 6 to 13 μg monocrotaline in its scale cover or about 1 to 2% of the moth’s systemic monocrotaline content. Based on estimates of the number of scales per forewing, the monocrotaline content of individual scales is calculated to be in the order of 0.1 and 0.2 ng monocrotaline per male and female scale, respectively. This amounts to concentrations of about 1 and 3%, values roughly at a par with the average systemic concentration (0.5-0.6%) previously determined for monocrotaline in Utetheisa. It is argued that the presence of pyrrolizidine alkaloid in the moth’s scale coating could account for the promptness with which adult Utetheisa are rejected by spiders. It is suggested further that chemical impregnation of scales with substances deterrent to predators may be more widespread among insects than generally assumed.

This study aimed to characterize the chemical composition of Aloysia polystachia, Acantholippia seriphioides, Schinus molle, Solidago chilensis, Lippia turbinata, Minthostachys mollis, Buddleja globosa, and Baccharis latifolia essential oils (EOs), and to evaluate their antibacterial activities and their capacity to provoke membrane disruption in Paenibacillus larvae, the bacteria that causes the American Foulbrood (AFB) disease on honey bee larvae. The relationship between the composition of the EOs and these activities on P. larvae was also analyzed. Monoterpenes were the most abundant compounds in all EOs. All EOs showed antimicrobial activity against P. larvae and disrupted the cell wall and cytoplasmic membrane of P. larvae provoking the leakage of cytoplasmic constituents (with the exception of B. latifolia EO). While, the EOs' antimicrobial activity was correlated most strongly to the content of pulegone, carvone, (Z)-β-ocimene, δ-cadinene, camphene, terpinen-4-ol, elemol, β-pinene, β-elemene, γ-cadinene, α-terpineol, and bornyl acetate; the volatiles that better explained the membrane disruption were carvone, limonene, cis-carvone oxide, pentadecane, trans-carvyl acetate, trans-carvone oxide, trans-limonene oxide, artemisia ketone, trans-carveol, thymol, and γ-terpinene (positively correlated) and biciclogermacrene, δ-2-carene, verbenol, α-pinene, and α-thujene (negatively correlated). The studied EOs are proposed as natural alternative means of control for the AFB disease.

Females of the moth Utetheisa ornatrix (Lepidoptera: Arctiidae) mate preferentially with males that excel in three quantitatively correlated attributes: body mass, systemic content of defensive pyrrolizidine alkaloid (derived from the larval diet), and glandular content of the courtship pheromone hydroxydanaidal (derived from the alkaloid). By so choosing, the females obtain direct phenotypic benefits (alkaloid and nutrient received with the spermatophore), and indirect genetic benefits (genes for large size, a heritable trait). We asked whether the female appraises the courting male on the basis of all three attributes, or whether, as had been postulated, she does so on the basis of the intensity of the pheromonal scent alone. We present data indicating that male possession of hydroxydanaidal is indeed the sole criterion of choice. Females fail to differentiate between males that differ in body mass or alkaloid content if the males lack hydroxydanaidal, but choose between males that are size-matched and alkaloid-free if one of the males has been experimentally endowed with hydroxydanaidal. We show moreover that females are able to differentiate between males that contain unequal quantities of hydroxydanaidal. Females abide by these criteria whether or not they themselves contain alkaloid. Their choice was also unaffected by whether they were confined singly with 2 males in small mating chambers, or were in groups of 10 with 20 males in large flight cages.

The earwig Doru taeniatum (Dermaptera, Forficulidae) has a pair of defensive glands, opening on the 4th abdominal tergite, from which it discharges a spray when disturbed. It aims the discharges by revolving the abdomen, a maneuver that enables it simultaneously to use its pincers in defense. The secretion contains two quinones (methyl-1,4-benzoquinone and 2,3-dimethyl-1,4-benzoquinone) present in the glands as a crystalline mass, together with pentadecane and a (presumably) aqueous phase. The gland openings are minute, with the result that virtually no quinone crystals are expelled with the spray. Only the two liquid phases are discharged, together with the ca. 1% quinone they carry in solution. Such a solute-economizing discharge mechanism appears to be without parallel among insect defensive glands.

The larva of the green lacewing ( Ceraeochrysa cubana ) (Neuroptera, Chrysopidae) is a natural predator of eggs of Utetheisa ornatrix (Lepidoptera, Arctiidae), a moth that sequesters pyrrolizidine alkaloids from its larval foodplant (Fabaceae, Crotalaria spp.). Utetheisa eggs are ordinarily endowed with the alkaloid. Alkaloid-free Utetheisa eggs, produced experimentally, are pierced by the larva with its sharp tubular jaws and sucked out. Alkaloid-laden eggs, in contrast, are rejected. When attacking an Utetheisa egg cluster (numbering on average 20 eggs), the larva subjects it to an inspection process. It prods and/or pierces a small number of eggs (on average two to three) and, if these contain alkaloid, it passes “negative judgement” on the remainder of the cluster and turns away. Such generalization on the part of the larva makes sense, because the eggs within clusters differ little in alkaloid content. There is, however, considerable between-cluster variation in egg alkaloid content, so clusters in nature can be expected to range widely in palatability. To check each cluster for acceptability must therefore be adaptive for the larva, just as it must be adaptive for Utetheisa to lay its eggs in large clusters and to apportion alkaloid evenly among eggs of a cluster.

Epilachnene [(5Z)-11-propyl-12-azacyclotetradec-5-en-14-olide], the principal component of the secretion of the pupal defensive hairs of the Mexican bean beetle (Epilachna varivestis), has antiinsectan activity. Both the R enantiomer of epilachnene, and the S enantiomer (the natural configuration of the compound), proved deterrent in a feeding bioassay with a predaceous coccinellid beetle (Harmonia axyridis). Moreover, both enantiomers proved active in a topical irritancy test with a cockroach (Periplaneta americana).

The carabid beetle Galerita lecontei has a pair of abdominal defensive glands that secrete a mixture of formic acid, acetic acid, and lipophilic components (long-chain hydrocarbons and esters). Formic acid, at the concentration of 80%, is the principal constituent. The beetle ejects the secretion as a spray, which it aims accurately toward parts of the body subjected to assault. At full capacity, the glands store 4.5 mg of formic acid (3% of body mass), enough for upward of six ejections. The beetle reloads the glands at a rate of 126 μg of formic acid per day. For the approximately 500 secretory cells of the glands, this means an hourly output of 10 ng of formic acid per cell, or about 5% of cell volume. Replenishing empty glands to their full formic acid load takes the beetle an estimated 37 days. Replenishing the 0.7 mg of formic acid expended in a single discharge takes 5.5 days.

The Sapindaceae (soapberry family) is a family of flowering plants with about 2000 species occurring from temperate to tropical regions throughout the world. Members of this family have been widely studied for their pharmacological activities; being Paullinia and Dodonaea good examples of genera containing species with these properties. Besides, the family includes many species with economically valuable tropical fruits, and wood (Rodriguez 1958), as well as many genera with reported anti-insect activity. Antioxidant, anti-inflammatory and anti-diabetic properties are the pharmacological activities most commonly described for this family (Sofidiya et al. 2008; Simpson et al. 2010; Veeramani et al. 2010; Muthukumran et al. 2011). These activities are in some cases accounted for isolated phenolic compounds such as prenylated flavonoids (Niu et al. 2010), but in many cases, it is still unknown which are the active principles. Indeed, there are many studies of complex mixtures (crude aqueous or ethanolic extracts) from different species in which several other pharmacological activities have been described without characterization of the active compounds [e.g. antimigrane (Arulmozhi et al. 2005), anti-ulcerogenic (Dharmani et al. 2005), antimalarial (Waako et al. 2005), anti-microbial (Getie et al. 2003)]. Phytochemical studies on Sapindaceae species are abundant and various kinds of natural products have been isolated and elucidated. Examples of these are flavonoids from Dodonaea spp. (Getie et al. 2002; Wollenweber & Roitman 2007) and Koelreuteria spp. (Mahmoud et al. 2001), linear triterpenes from Cupaniopsis spp. (Bousserouel et al. 2005) and caffeine, xanthenes and cathequines from Paullinia spp. (Benlekehal et al. 2001; Sousa et al. 2009). All these compounds are naturally occurring in almost every plant family, however, the Sapindaceae do produce an unusual group of secondary metabolites: the cyanolipids (Avato et al. 2005). Eventhough these compounds exhibit a potential health hazard for humans and animals, for the plants, cyanolipids may have a protective physiological role. However, not many investigations have been developed involving the study of the ecological interactions among the plants producing them and other sympatric organisms. On the other hand, the toxicity of these cyanocompounds might be a potential source of pesticides. Indeed, not only cyanocompounds, but also a wide range of species of Sapindaceae have been tested on their anti-insect activity. Several extracts, fractions or pure compounds of different phenological stages, have been tested against diverse species of lepidopterans, dipterans and coleopterans of major importance in agriculture as well as in veterinary and medical applications. Examples of this include the larvicidal activity of Magonia pubescens against Aedes aegypti

The ethanolic extract of ripe fruits of Melia azedarach (Meliaceae) and its subfractions were tested against four insect species, portraying important agricultural pests. Five limonoids were isolated: two tirucallane type triterpenoids never isolated before from this species (21α-methylmelianodiol, 21β-ethylmelianodiol), as well as three ring C-seco limonoids previously reported on this tree (1-O-detigloyl-1-O-cinnamoylohchinolal, 1-O-detigloyl-1-O-benzoylohchinolal and ohchinolal). The complete NMR data of these natural products are reported here. Different patterns of activity were found among the products tested against the different pest models, emphasizing the value of testing potential biocontrol products against different insect targets., This work was supported by grants from Faculty of Chemistry (FQ), Uruguayan Technological Laboratory (LATU), CSIC-UR, Program for the Development of Basic Sciences (PEDECIBA) (grant PNUD- URU/06/004). Facundo Ibáñez and Roberto Zoppolo from the Instituto Nacional de Investigación Agropecuaria (INIA, Uruguay) provided de limonin standard.

Forest plantations in Uruguay have doubled in the past decade, withEucalyptusspp. leading this growth. The bronze bug,Thaumastocoris peregrinus(Heteroptera: Thaumastocoridae), originally restricted to Australia, is an important emerging pest ofEucalyptusplantations in the Southern hemisphere.T. peregrinusfeeds on matureEucalyptusleaves, causing them to turn brown and often fall from the tree. Although population dynamics and behavioural patterns are not clearly understood, circumstantial observations suggest that males and nymphs aggregate. We used gas chromatography coupled to mass spectrometry to analyze volatile organic compounds emitted by virgin males and females, and characterized a male-specific compound, 3-methylbut-2-enyl butanoate, based on mass spectral data and chromatographic comparison with a synthetic standard. We also performed Y-olfactometer bioassays to test the attraction of virgin males and females toward live virgin males, male volatile extracts, and synthetic 3-methylbut-2-enyl butanoate. Males were attracted toward conspecific males, while virgin females showed no preference, suggesting that male volatiles are not involved in sexual communication. Further olfactometer tests showed that males were attracted to male volatile extracts and to synthetic 3-methylbut-2-enyl butanoate. The ecological significance of this compound and its potential use for the management ofT. peregrinusinEucalyptusforests will be further investigated.

Ladybird beetles produce a large number of defensive alkaloids. Previous studies suggest that the structural diversity of these endogenous alkaloids can be traced to a common biosynthetic route based on the condensation of several acetate units. In this study, adults of Epilachna paenulata, a phytophagous neotropical species, were fed on diet enriched with potential precursors (sodium acetate, fatty acids and the amino acids lysine and ornithine) labeled with stable isotopes ((13)C, (2)H and (15)N). Labeled acetate was incorporated into the structurally related homotropane and piperidine alkaloids. The later also showed incorporation of [methyl-(2)H3] stearic acid. Our results hence support a fatty acid pathway for the biosynthesis of E. paenulata alkaloids. To our knowledge, this is the first report on the incorporation of a labeled fatty acid into a defensive piperidine alkaloid in insects.

Cryptoblabes gnidiella Milliere (Lepidoptera: Pyralidae) is an economically important exotic pest of vineyards in Southern Brazil and Uruguay. The sex pheromone of C. gnidiella was identified as a mixture of (Z)-11-hexadecenal and (Z)-13-octadecenal, and has been used to monitor populations of this pest in Israel. The development of mating disruption for this species may be hampered by the chemical instability of the natural pheromone components. Therefore, studies on more stable pheromone analogs may provide tools for a control strategy based on behavior-modifying chemicals. We report here the electrophysiological and behavioral responses of C. gnidiella males to (Z)-9-tetradecenyl formate and (Z)-11-hexadecenyl formate, structural analogs of the pheromone components. In gas chromatography-electroantennogram detection (GC-EAD) studies, both analogs elicited responses from C. gnidiella male antennae. Pre-exposure to the formates did not affect the subsequent EAD responses to the natural pheromone components. The formates acted as pheromone antagonists in wind tunnel tests, inhibiting the responses of males toward both synthetic pheromone and calling females. In the field, captures of males in pheromone-baited traps decreased, in a dose-response pattern, when different amount of formates were added to the pheromone. These pheromone antagonists, thus, are potentially useful as mating disruptants for C. gnidiella in commercial vineyards.

The chemical composition of the cold-pressed oils obtained from three mandarin cultivars (“Comun,” “Malvasio” and “Ellendale”) and two mandarin hybrids (“Ortanique” and “Malaquina”) grown in Uruguay were examined using a combination of alumina column chromatography and capillary GC. Forty-five constituents were characterized in the oils with the limonene content varying from 75.26–96.23%. The composition and olfactory characteristics of these oils were compared with those of Italian mandarin oil and Uruguayan sweet orange oil. It was found that the “Ortanique” and “Ellendale” oils were very different from normal mandarin oil, with great similarity in composition and olfactory characteristics to sweet orange oil. The oil of “Malaquina” is also similar more to sweet orange oil than mandarin oil although it is quite rich in aliphatic aldehydes, particularly decanal. The oil of the cv. Malvasio has a composition which is between mandarin and sweet orange oils. The oil of cv. Comun is the only one fou...

6 pages, 2 tables.-- Available online Jun 24, 2008. We evaluated the anti-insectan activity of extracts from different vegetative parts of ten plant species native to Uruguay. The selected plants belong to five families: Bignoniaceae: Clytostoma callistegioides, Dolichandra cynanchoides, Macfadyena unguis-cati; Sapindaceae: Dodonaea viscosa, Allophylus edulis, Serjania meridionalis; Lamiaceae: Salvia procurrens, Salvia guaranitica; Solanaceae: Lycium cestroides; and Phytolaccaceae: Phytolacca dioica. The extracts were evaluated in independent bioassays against four insect pests and one beneficial insect. Aphid settling inhibition was evaluated with a grass specialist, Rhopalosiphum padi, and a feeding generalist, Myzus persicae (both Hemiptera: Aphididae). Antifeedant activity was tested with adults of the specialist Epilachna paenulata (Coleoptera: Coccinellidae) and larvae of the generalist Spodoptera littoralis (Lepidoptera: Noctuidae). Finally, contact toxicity was assessed with honey bees, Apis mellifera (Hymenoptera: Apidae). Strong settling inhibition (SI) activity (expressed as %SI, where 100% means complete inhibition by the extract) was found only for the twig extracts of A. edulis (Sapindaceae) against M. persicae (%SI = 77 ± 4). Antifeedant activity (expressed as % of feeding reduction (FR), where 100% means no consumption on extract-treated diet) against E. paenulata was significant for the leaf extracts of L. cestroides (Solanaceae) (%FR = 100 ± 0) as well as of all Bignoniaceae and Sapindaceae species. No extracts were active against S. littoralis larvae, and most of them were innocuous to honey bees, with the exception of L. cestroides and S. meridionalis leaf extracts. OPCW (grant L/ICA/ICB/111817/06), TWAS (grant RGA 05-318), MAEC-AECI (LC fellowship), IFS (grant F/3079-1), FIRCA-NIH, DGI-Spain (CTQ2006-15597-C02-01/PPQ), PEDECIBA (grant PNUD-URU/06/004) and CSIC-UdelaR.

Crocidosema aporema (Walsingham) is a major pest of legumes in the southern cone of Latin America. The mating behaviour of two allopatric populations (Uruguay and Brazil) of C. aporema kept in captivity was studied by observing the posture of calling females, the temporal pattern of pheromone emission and mating, and the response of males to calling females in olfactometer tests. Female calling and mating was observed during the scotophase, from the first to the seventh night after adult emergence. Male response was evaluated at night using a single calling female in a Y-shaped olfactometer. Females adopted a characteristic calling posture, extruding the pheromone gland from the tip of the abdomen. Most females started calling during the second scotophase, and all females called from the third, between the fifth and seventh hours after the onset of the scotophase. Most of the couples mated once throughout the experiment, between the third and sixth night and during the middle of the dark phase. Males preferentially chose the female arm in olfactometer tests, considering both the first arm chosen and the number of visits during the observation period. Our results describe for the fi rst time the temporal pattern associated to the reproductive behaviour of C. aporema. We also provide evidence that this tortricid is monoandrous, and that pheromones are used in intersexual communication for mate finding. Our data will be used to optimize the collection of female sex pheromones for chemical characterization in order to develop a monitoring tool for this pest.

Epinotia aporema (Walsingham) is a Neotropical pest of legumes in southern South America. Its importance has increased during the last decade owing to the significant growth of soybean production in the region. Monitoring of E. aporema is difficult due to the cryptic behavior of the larvae, and hence, chemical control is carried out preventively. We analyzed the female-produced sex pheromone so as to develop monitoring traps and explore pheromone-based control methods. We analyzed pheromone gland extracts by combined chromatographic, spectrometric, and electrophysiological methods. Based on the comparison of retention indices, mass spectra, and electroantennogram (EAD) activity of the insect-produced compounds with those of synthetic standards, we identified two EAD-active compounds, (Z,Z)-7,9-dodecadienol and (Z,Z)-7,9-dodecadienyl acetate (15:1 ratio), as sex pheromone components of E. aporema. We also studied the behavior of males in wind tunnel tests using virgin females and different combinations of synthetic standards (15:1, 1:1, and 1:0 alcohol/acetate) as stimuli. A significantly greater percentage of males reached the chemical source with the 15:1 synthetic mixture than with any of the other treatments, indicating that these two compounds are pheromone components.

Coccinellid beetles contain a variety of defensive alkaloids that render them unpalatable to predators. Epilachna paenulata (Coleoptera: Coccinellidae) is a South American ladybird beetle that feeds on plants of the Cucurbitaceae family. The defensive chemistry of E. paenulata has been characterized as a mixture of systemic piperidine, homotropane, and pyrrolidine alkaloids. Whole body extracts of adult beetles contain four major alkaloids: 2-(2'-oxopropyl)-6-methylpiperidine (1); 1-(6-methyl-2,3,4,5-tetrahydro-pyridin-2-yl)-propan-2-one (2); 1-methyl-9-azabicyclo[3.3.1]nonan-3-one (3); and 1-(2''-hydroxyethyl)-2-(12'-aminotridecyl)-pyrrolidine (4). Comparative studies of the defensive chemistry of eggs, larvae, pupae, and adults showed differences in alkaloid composition and concentration among life stages. While adults contained mainly the homotropane 1-methyl-9-azabicyclo[3.3.1]nonan-3-one (3), eggs showed the highest concentration of the piperidine 2-(2'-oxopropyl)-6-methylpiperidine (1). We studied the origin of this alkaloid in the eggs by feeding newly emerged, virgin adult beetles with [2-(13)C]-labeled acetate, and by performing crosses between (13)C-fed and unlabeled males and females. GC-MS analysis of alkaloids from (13)C-fed males and females showed high incorporation of (13)C into the alkaloids, as evidenced from a 20-30% increase of isotopic peaks in diagnostic fragment ions, confirming the expected endogenous origin of these alkaloids. In addition, analyses of eggs from different crosses showed that labeled alkaloids from both parents are incorporated into eggs, indicating that E. paenulata males transfer alkaloids to the females at mating. Biparental endowment of chemical defenses into eggs has been shown previously in insects that acquire defensive compounds from dietary sources. To our knowledge, this is the first report of biparental egg endowment of endogenous defenses.

The first syntheses of two deoxythiocyanocyclitols (4-deoxy-4-thiocyano- l -chiro-inositol and deoxythiocyanoconduritol F) and two deoxysulfonylcyclitol acetals are reported by a chemoenzymatic enantioselective route. The compounds were prepared by a sequence of enzymatic and ruthenium-catalyzed dihydroxylations, and the results were studied regarding reaction conditions and co-catalyst for different derivatives. The new compounds were included in a minilibrary of deoxygenated cyclitols and evaluated for their capacity to influence the feeding behavior of Epilachna paenulata (Coleoptera: Coccinellidae), a common pest of the Curcubitaceae crops.