Spodoptera Larvae Research Articles

Acute, synergistic and antagonistic effects of some aromatic compounds on the Spodoptera littoralis Boisd. (Lep., Noctuidae) larvae

The efficacy of 30 aromatic compounds and their mutual binary combinations was tested for acute toxicity against the larvae Spodoptera littoralis. Based on a comparison of the lethal doses, the thymol, carvacrol and trans-anethole were selected as the most effective, and LD50 was estimated for them at 9, 15 and 18μg/larva, respectively, and LD90 at 28, 35 and 41μg/larva, respectively. In total, 435 binary combinations were tested, of which 135 combinations showed a significant synergic effect, while 150 combinations showed a significant antagonistic effect on mortality. Only 6 substances were identified as being able to create a synergic effect with more than 20 substances: γ-terpinene, limonene, p-cymene, trans-anethole, borneol and camphor. l-carvone and gallic acid created an antagonistic effect with the highest frequency.The highest synergic effect was achieved for the combination of camphor and borneol, with the place of expected mortality estimated at 4.8% and mortality at 88.6%. In order to verify the synergic interaction of camphor and borneol, the effectiveness in terms of acute toxicity for S. littoralis larvae was determined for three fundamental mixing ratios of the substances. Significantly different LD50 values (88 and 134μg/larva, respectively) were found for camphor/borneol mixtures prepared in the ratios 2:1 and 1:1, respectively.The information learned can thus be used in the development of new botanical insecticides based on EOs, and particularly in the creation of formulations.

Efektifitas Ekstrak Daun Nimba (Azadirachta indica) dengan Pelarut Metanol dan Air terhadap Hama Spodoptera litura F.

Synthetic insecticide which is commonly used to control pest has negative impact to human health and environment. Besides, it is not effective to prevent pest. However, the usage of insecticide made of plant can provide an alternative because it has less side effects and easy degradation in nature. The Nimba plant ( Azadirachta indica ) is know to have insecticide element, anti-eating, and able to disturb the growth of insects. This research was carried out at the laboratory of plant protection Faculty of Agriculture and the Laboratory of Biology Faculty of Mathematics and Natural Science, Riau University. The research was carried out by factorial experiment in Completely Randomized Design with three factors, seven levels, and five replications. The three factors were the spraying of nimba leaves extract on the larvae Spodoptera litura by different solvent and water thinner which were methanol solvent and acetone thinner, methanol solvent and water thinner, and water solvent and water thinner. The treatment of each factor resulted in the different extract concentration of nimba leave. Those are 0%, 1%, 3%, 6%, 10%, 15%, and 20%. The result of research proved that nimbi leave extract using methanol solvent and acetone thinner had better result in poisoning pest. At 1% concentration level it was effective to prevent larvae S. litura which was equivalent with the concentration of 15% nimbi leave extract with methanol solvent and water thinner, and also with 20% nimbi leave extract with water solvent and water thinner.

Feeding non-preference by Spodoptera frugiperda and Spodoptera eridania on tomato genotypes

Larvae of the genus Spodoptera spp. are highly polyphagous and can cause economical losses in several agricultural crops. Given their growing importance in the tomato crop, especially for industry, this work aimed to evaluate the feeding non-preference by larvae of Spodoptera frugiperda (J. E. Smith, 1797) and Spodoptera eridania (Cramer, 1782) on tomato genotypes and classify them by the levels of resistance. The commercial cultivar Santa Clara was set as the susceptible standard and line PI 134417 as the resistant standard to evaluate the lines PI 134418, PI 126931, LA 462 and LA 716. Feeding non-preference tests were performed under non-choice and free-choice conditions to evaluate the genotype attractiveness to larvae at predetermined times after their release, as well as the leaf area consumed. Overall, the genotypes LA 716 and PI 126931 were the least attractive to S. frugiperda, whereas Santa Clara was the most attractive and consumed. For S. eridania, the genotypes PI 126931, LA 462, LA 716 and PI 134418 were the least preferred for feeding, and Santa Clara and PI 134417 were the most attractive and consumed. The genotypes LA 716 and PI 126931 are moderately resistant to S. frugiperda and S. eridania; PI 134418 and LA 462 are moderately resistant to S. eridania; PI 134417 is susceptible to S. frugiperda and S. eridania; and Santa Clara is highly susceptible to both S. frugiperda and S. eridania.

Arthropod Abundance in Two Maize Fields in Western Central Mexico

Arthropod abundance was monitored in maize (Zea mays L.) crops on two farms located in western central Mexico during a single growing season. At the first farm (El Calvario, Michoacán), a no-tillage system was used in maize plots, while in the second farm (Singuio, Michoacán), a conventional tillage system was established. At these sites, sampling was conducted on nine occasions at seven day-intervals. Soil arthropods were captured using pitfall traps. At each sample point, maize plants were randomly selected and the number of arthropods observed on each plant was recorded. Poecilus mexicanus Chaudoir (Coleoptera: Carabidae) was the most abundant insect captured and comprised 75% (n = 2530) of the total capture of arthropods. Other carabid species together represented 18% of the total capture of arthropods at these sites and was significantly greater in the no-tillage farm compared to the conventional tillage farm. Staphylinids were the second most common group and were more abundant in the no-tillage than conventional tillage farm; Platydracus sp. Thomson (Coleoptera: Staphylinidae) was the most abundant staphylinid captured and was most abundant in the no-tillage farm. No differences between the abundance of the remaining arthropods were observed between the farms. The abundance of arthropods associated with maize plants on these two farms was not clearly affected by the type of cultivation. Over the course of the study, the abundance of fall armyworm larvae Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) was very low (maximum 0.16 ± 0.02 insects/plot) on both farms; infestation by this pest did not differ significantly between farms. In conclusion, the no-tillage farm seemed to favor some beneficial predators present in/on the soil (e.g., carabids and staphylinids), possibly because these insects exhibit a preference for more diverse habitats and because they are more sensitive to the type and timing of cultivation practices.

ISOLATION AND PHENOTYPIC CHARACTERISATION OF MORPHOLOGY IN FUNGUS Beauveria bassiana (Balsamo) Vuillemin COLONY NATURALLY FROM LEAF SURFACE, SOIL, AND INSECT AS HOST IN TOMATO PLANTATION

Virulence of fungus Beauveria bassiana as pathogen on insect can be predicted according to phenotypic character in colony morphology. First of all, isolates of three different habitats were taken. Furthermore, their phenotypic characters was further characterised in B. bassiana colony and the colony growth rate was also monitored. The three natural habitats comprised insects, soil in tomato plantation and the surface of tomato leaves. The result showed that B bassiana isolate managed to be isolated from the three natural habitats involving larva Spodoptera litura and Helicoverpa armigera , the soil, and surface of tomato leaves. B bassiana isolate of insect habitat represented phenotype in colony morphology with curved character, while isolate of the leaves’ surface and soil indicated phenotype in colony morphology with raised and bowl-shaped character. In addition to the colony characters, varied growth rate was also indicated by isolate from each habitat. Isolate of insect with curved colony character represented higher growth rate than that of the leaves’ surface or the soil with raised and bowl-shaped colony character. The colony with curved character represented phenotypic character of isolate B bassiana with high growth rate. Thus, B. bassiana isolate with the curved colony of insect served as an isolate which was expected to be virulent as controlling agent to biological elements. Keywords: B. bassiana isolate, phenotypic characters in colony morphology, colony growth rate, habitat of fungus Normal 0 false false false EN-US X-NONE X-NONE

Insecticidal effect of furanocoumarins from fruits of Angelica archangelica L. against larvae Spodoptera littoralis Boisd.

The essential oil (EO) and extracts (EXs) obtained from the seeds of Angelica archangelica were used to determine the efficacy in terms of chronic and acute toxicity, antifeedancy and growth inhibition of Spodoptera littoralis larvae. The EO and the EXs were analyzed by GC/MS and HPLC. The EO contained β-phellandrene as the major substance (60%). Furanocoumarins were identified in the EXs obtained using organic solvents, with the majority content of imperatorin (50–56%). Their varying efficacy was caused by the different composition of the EO and EXs obtained. Significant acute toxicity was caused only by the EO (LD50 96μg/larva). Significantly higher chronic toxicity was found for the EXs obtained using organic solvents (LD50 was estimated at 0.32, 0.82 and 0.52mgg−1 for benzene, acetone and methanol, respectively), compared to the EO (LD50 7.53mgg−1). All the tested EXs and the EO caused growth inhibition. The highest larval growth inhibition was caused by the benzene extract, with ED50 estimated at 2.4μgg−1. All EXs and the EO also showed antifeedant activity. However, the benzene extract showed the highest efficacy (ED50 0.31μgcm−2), while the least efficacy was shown by the water extract (ED50 1.92μgcm−2). In order to determine the dependence of biological efficacy of the EXs, LD50 and ED50 values were subjected to regression and correlation analysis. The analysis showed dependence between the total content of furanocoumarins in the extracts and chronic toxicity (R2=0.8451; P<0.01) or larval growth inhibition (R2=0.8941; P<0.01). This dependence was also confirmed for all individual furanocoumarins except bergapten, which showed no dependence.Based on a comparison of the determined efficacy and yield of the extracts, extracts from A. archangelica seeds obtained using methanol can be recommended as suitable for the development of botanical insecticides against S. littoralis larvae.

Record of New Species of Parasitoids on Larvae of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and Dichomeris famulata Meyrick (Lepidoptera: Gelechiidae) in Maize (Zea mays L.) in Brazil

The knowledge of the flow of parasitoids in cultivated areas is a practice that should be adopted for choosing a best method for the regulation of pest populations. The objective of this study was to determine the occurrence of parasitoids associated with lepidopterous larvae Spodoptera frugiperda (J. E. Smith) (Noctuidae) and Dichomeris famulata Meyrick (Gelechiidae) in maize under organic and conventional production system. The experiment was conducted at the National Research Center for Maize and Sorghum (CNPMS) in Sete Lagoas, Minas Gerais State, Brazil. During all cycle of maize (variety BR 106) for each production system three times a week, 10 plants and/or 10 ears were sampled from each of the 24 plots. At the laboratory larvae were distributed in individual rearing containers with artificial diet until the end of the biological cycle. Hymenoptera parasitoids emerged from S. frugiperda included the Ichneumonidae Campoletis flavicincta, Colpotrochia sp. nov., Eiphosoma laphygmae e Ophion flavidus and the Braconidae Chelonus (Chelonus) insularis, Dolichozele koebelei e Exasticolus sp. nov. Colpotrochia sp. nov., Dolichozele koebelei and Exasticolus sp. nov. are registered for the first time parasitizing S. frugiperda. From larvae of D. famulata emerged the Braconidae Cotesia sp., Glyptapanteles sp., Phanerotoma sp. (Group Fuscovaria) and Chelonus (Microchelonus) sp. nov. (first occurrence in D. famulata). The results indicate the potential of the parasitoids to natural biological control agents for use in integrated management programs of phytophagous insects in maize.

Insecticidal activities ofGinkgo bilobaseed coat extracts againstSpodoptera exigua(Lepidoptera: Noctuidae)

AbstractThe present study relates to a methanol extract of the seed coat ofGinkgo biloba, and tested particularly on the third instar larvae ofSpodoptera exigua. The extract was found to have an inhibitory effect on the growth of the larvae besides bringing a change in the nutrient reserves in the body of the insect. Topical application of five different doses of the methanol extract resulted in a mortal effect to third instar larvae ofS. exiguathat is very much dependent on the dose as well as duration of exposure. Lower doses revealed lower mortality after 24 h of application. At doses of 1.00, 2.00, 4.00, 8.00 and 16.00 ng/larva, mortalities were 9.25, 26.07, 50.32, 56.28 and 92.44%, respectively. The dose for 50% mortality (LD50) of methanol extracts by applied by a topical method with 1 µL of acetone solution was 1.92 ng/larva. Nutrient reserves like protein, glycogen and lipid are known to regulate pupation and adult emergence. These reserves have been found to be lower in treated larvae, indicating the insecticidal role of methanol extracts fromG. bilobaagainst third instar larvae ofS. exigua.

Quantitative Evaluation of (+)-Δ3-Carene Metabolites from Living Larvae of Spodoptera litura by Headspace Solid-phase Microextraction

In this study, a simple, rapid, and solvent-free method for quantitative determination of (+)-Δ(3)-carene metabolites released from larvae of Spodoptera litura was developed using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Further, we calibrated and validated the HS-SPME method for the quantitation of the loss of substrates owing to their biotransformation by the larvae. (+)-Δ(3)-Carene metabolites were extracted at 25°C for 30 min using an SPME fiber over a period of 24 h; the SPME fiber used was made of divinylbenzene-carboxen-polydimethylsiloxane. This technique was used to analyze the time course of the larval headspace, and the results of this analysis were used to propose a metabolic pathway. An external calibration curve was used for the quantification of (+)-Δ(3)-carene metabolites from the larval headspace. The total release volume of the larvae was calculated at 24 % of the dosage. Moreover, the biotransformation by S. litura began 2 h after it was injected with (+)-Δ(3)-carene. The method was validated by calculating the limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, and linearity. The LOD and LOQ corresponded to signal/noise ratios of 3 and 10, respectively. The LODs ranged from 0.002 to 0.003 nmol/mL, and the LOQs ranged from 0.007 to 0.009 nmol/mL. This method was sensitive enough to quantitate the (+)-Δ(3)-carene metabolites released from the Spodoptera larvae. The developed SPME method can have wide applications in various in vivo larval metabolite studies.

Crystallization of α- and β-carotene in the foregut of Spodoptera larvae feeding on a toxic food plant

In the animal kingdom, carotenoids are usually absorbed from dietary sources and transported to target tissues. Despite their general importance, the uptake mechanism is still poorly understood. Here we report the “red crop” phenomenon, an accumulation of α- and β-carotene in crystalline inclusions in the enlarged foregut of the polyphagous Spodoptera larvae feeding on some potentially toxic plant leaves. The carotene crystals give the insect foregut a distinctive orange-red color. The crystals are embedded in a homogenous lawn of the bacterium Enterococcus casseliflavus, but the carotene seems to be selectively taken from the food plant. Caterpillars which fail to develop these carotene crystals exhibit a high mortality or fail to develop to adulthood. The crystallization of carotene and the enlargement of the foregut thus appears to manifest a multiple-step physiological adaptation of the insects to toxic food plants.

Interaction of Bacillus thuringiensis vegetative insecticidal protein with ribosomal S2 protein triggers larvicidal activity in Spodoptera frugiperda.

Vegetative insecticidal protein (Vip3A) is synthesized as an extracellular insecticidal toxin by certain strains of Bacillus thuringiensis. Vip3A is active against several lepidopteran pests of crops. Polyphagous pest, Spodoptera frugiperda, and its cell line Sf21 are sensitive for lyses to Vip3A. Screening of cDNA library prepared from Sf21 cells through yeast two-hybrid system with Vip3A as bait identified ribosomal protein S2 as a toxicity-mediating interacting partner protein. The Vip3A-ribosomal-S2 protein interaction was validated by in vitro pulldown assays and by RNA interference-induced knockdown experiments. Knockdown of expression of S2 protein in Sf21 cells resulted in reduced toxicity of the Vip3A protein. These observations were further extended to adult fifth-instar larvae of Spodoptera litura. Knockdown of S2 expression by injecting corresponding double-stranded RNA resulted in reduced mortality of larvae to Vip3A toxin. Intracellular visualization of S2 protein and Vip3A through confocal microscopy revealed their interaction and localization in cytoplasm and surface of Sf21 cells.

Fatty Acid-amino Acid Conjugates Diversification in Lepidopteran Caterpillars

Fatty acid amino acid conjugates (FACs) have been found in noctuid as well as sphingid caterpillar oral secretions; in particular, volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants. These induced volatiles, in turn, attract natural enemies of the caterpillars. In a previous study, we showed that N-linolenoyl-L-glutamine in larval Spodoptera litura plays an important role in nitrogen assimilation which might be an explanation for caterpillars synthesizing FACs despite an increased risk of attracting natural enemies. However, the presence of FACs in lepidopteran species outside these families of agricultural interest is not well known. We conducted FAC screening of 29 lepidopteran species, and found them in 19 of these species. Thus, FACs are commonly synthesized through a broad range of lepidopteran caterpillars. Since all FAC-containing species had N-linolenoyl-L-glutamine and/or N-linoleoyl-L-glutamine in common, and the evolutionarily earliest species among them had only these two FACs, these glutamine conjugates might be the evolutionarily older FACs. Furthermore, some species had glutamic acid conjugates, and some had hydroxylated FACs. Comparing the diversity of FACs with lepidopteran phylogeny indicates that glutamic acid conjugates can be synthesized by relatively primitive species, while hydroxylation of fatty acids is limited mostly to larger and more developed macrolepidopteran species.

Pattern and Consequences of Floral Herbivory in Four Sympatric Ipomoea Species

Flowers are expected to be under strong selection pressure to be attractive to pollinators. Yet, floral traits that serve in pollinator attraction may inadvertently attract animals that consume flowers. We expected animals to utilize floral cues in targeting plants to attack so for three field seasons we examined florivory in four sympatric Ipomoea species that differed in their pollination syndrome (flower color and shape) as well as their geographic origin (native vs. introduced). Most of the damage to Ipomoea flowers was caused by larval Spodoptera spp. that consumed all or parts of the corolla, pistil and stamens. There was no overall difference in damage levels to flowers of the bee or hummingbird-pollinated plants. However, florivores exhibited a strong preference for the native, bumble bee-pollinated I. cordatotriloba relative to the remaining three non-native Ipomoea species. The non-native, hummingbird-pollinated I. hederifolia and I. quamoclit consistently experienced the lowest florivory rates. There were reproductive consequences to florivory as damaged flowers had reduced fruit set. Seed set was not influenced by corolla damage, but was reduced when flowers suffered damage to reproductive organs. The results of our study suggest that flower-eating insects are not focusing in on traits associated with different pollination syndromes, but are preferentially visiting the native Ipomoea species, and this may contribute to the successful invasion of introduced Ipomoea plants that suffer reduced damage levels.

New Haemolytic Potential Assay on an Alternative Insect Model

A new screening test of a haemolytic potential is presented on Spodoptera larvae in vivo. The assay was evaluated using phenylhydrazine, the well-known xenobiotic which induces haemolysis in mammals. Haemocyte disintegration causes changes in total haemocyte counts and differentials. It is shown that only qualitative evaluation of panoptically stained haemolymph smears is sufficient, fast and cheap to detect haemolytic potential. The presented assay also prevents unneeded, non-ethical use of vertebrates.

Influence of polyploidy on insect herbivores of native and invasive genotypes of Solidago gigantea (Asteraceae)

Herbivores are sensitive to the genetic structure of plant populations, as genetics underlies plant phenotype and host quality. Polyploidy is a widespread feature of angiosperm genomes, yet few studies have examined how polyploidy influences herbivores. Introduction to new ranges, with consequent changes in selective regimes, can lead to evolution of changes in plant defensive characteristics and also affect herbivores. Here, we examine how insect herbivores respond to polyploidy in Solidago gigantea, using plants derived from both the native range (USA) and introduced range (Europe). S. gigantea has 3 cytotypes in the US, with 2 of these present in Europe. We performed bioassays with generalist (Spodoptera exigua) and specialist (Trirhabda virgata) leaf-feeding insects. Insects were reared on detached leaves (Spodoptera) or potted host plants (Trirhabda) and mortality and mass were measured. Trirhabda larvae showed little variation in survival or pupal mass attributable to either cytotype or plant origin. Spodoptera larvae were more sensitive to both cytotype and plant origin: they grew best on European tetraploids and poorly on US diploids (high mortality) and US tetraploids (low larval mass). These results show that both cytotype and plant origin influence insect herbivores, but that generalist and specialist insects may respond differently.

Evaluación del comportamiento del complejo Spodoptera con la introducción de algodón transgénico al Tolima, Colombia

Se comparó el comportamiento de las larvas del complejo Spodoptera (Lepidoptera: Noctuidae) entre lotes comerciales de algodón convencional y genéticamente modificado (Cry1Ac) en el Tolima, Colombia. Se evaluaron 83 cultivos de algodón (315 ha) y sus respectivos refugios (12,6 ha) en tres estados de desarrollo: vegetativo, reproductivo y maduración. En cada visita se seleccionaron al azar siete plantas por hectárea y se registró el número de larvas de Spodoptera frugiperda, S. ornithogalli y S. sunia, el tamaño (pequeñas &lt; 0,5 cm, medianas entre 0,5 y 1,5 cm, y grandes &gt; 1,5 cm) y su ubicación en la plantas (hojas, flores y cápsulas). En el análisis de los datos se utilizó una prueba de dependencia no paramétrica de Ji-cuadrado (X2). La dependencia del porcentaje de larvas del complejo Spodoptera por planta fue significativamente mayor (0,0021) en las plantas transgénicas (11,98% SE 4,03) que en las convencionales (9,13% SE 3,08). Este patrón se conservó al analizar los datos por especie y estado de desarrollo de la planta. En ambos materiales genéticos se registró una dependencia espacial significativa (0,0001) entre las especies observadas y las estructuras de la planta: S. frugiperda predominó en flores y cápsulas, S. ornithogalli, en hojas y flores y S. sunia, en hojas. No hubo una dependencia significativa entre los materiales genéticos y las estructuras vegetales con el tamaño de las larvas. Se registraron larvas de todos los tamaños en flores y cápsulas, estructuras donde la expresión de la proteína Bt es baja.

Evaluation of a PK/PBAN analog with an ( E)-alkene, trans-Pro isostere identifies the Pro orientation for activity in four diverse PK/PBAN bioassays

The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a multifunctional role in an array of important physiological processes in a variety of insects. An active core analog containing an ( E)-alkene, trans-Pro isosteric component was evaluated in four disparate PK/PBAN bioassays in four different insect species. These bioassays include pheromone biosynthesis in the moth Heliothis peltigera, melanization in the larval Spodoptera littoralis, pupariation acceleration in the larval fly Neobellieria bullata, and hindgut contraction in the cockroach Leucophaea maderae. The conformationally constrained analog demonstrated activity equivalent to parent PK/PBAN peptides of equal length in all four PK/PBAN bioassays, and matched and/or approached the activity of peptides of natural length in three of them. In the melanization bioassay, the constrained analog exceeded the efficacy (maximal response) of the natural PBAN1-33 by a factor of 2 (at 1 nmol). The results provide strong evidence for the orientation of Pro and the core conformation adopted by PK/PBAN neuropeptides during interaction with receptors associated with a range of disparate PK/PBAN bioassays. The work further identifies a scaffold with which to design mimetic PK/PBAN analogs as potential leads in the development of environmentally favorable pest management agents capable of disrupting PK/PBAN-regulated systems.

Slow cell infection, inefficient primary infection and inability to replicate in the fat body determine the host range of Thysanoplusia orichalcea nucleopolyhedrovirus

Thysanoplusia orichacea multicapsid nucleopolyhedrovirus (ThorMNPV) carrying an enhanced green fluorescent protein (EGFP) gene expression cassette (vThGFP) was used to study host-range mechanisms. Infection kinetics showed that vThGFP replication in Sf21 cells was too slow to suppress cell growth. Wide-host-range Autographa californica MNPV (AcMNPV) could speed up vThGFP infection and enhance the vThGFP infection rate in Sf21 cells. The enhancement was not due to recombination, as no recombinant virus was isolated from co-infection by plaque assay. No improvement of vThGFP infection in Sf21 was found by AcMNPV cosmid transactivation assay. However, culture medium from Sf21 cells infected with AcMNPV did enhance vThGFP replication in Sf21. Third-instar larvae of Spodoptera frugiperda, S. exigua and Helicoverpa zea were not killed by feeding with vThGFP polyhedra but were killed by intrahaemocoelic injection using budded viruses (BVs). This suggested that insufficient BVs were generated during the primary infection in the midgut. vThGFP infected haemocytes, tracheae and Malpighian tubules but not fat bodies of larvae of S. frugiperda, S. exigua and H. zea. Third-instar S. frugiperda larvae co-infected by injection with vThGFP and vAcDsRed2, an AcMNPV expressing a red fluorescent protein gene, showed EGFP expression in the fat body. This result suggests that vAcDsRed2 could help vThGFP to replicate in the fat body or trans-activate EGFP expression in the fat body. All these results suggested that slow cell infection, insufficient primary infection and inability to replicate in the fat body control the host range of ThorMNPV.

Fatty Acid Amides, Previously Identified in Caterpillars, Found in the Cricket Teleogryllus taiwanemma and Fruit Fly Drosophila melanogaster Larvae

Fatty acid amides (FAAs) are known elicitors that induce plants to release volatile compounds that, in turn, attract foraging parasitoids. Since the discovery of volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] in the regurgitant of larval Spodoptera exigua, a series of related FAAs have been identified in several other species of lepidopteran caterpillars. We screened 13 non-lepidopteran insects for the presence of FAAs and found that these compounds were present in adults of two closely related cricket species, Teleogryllus taiwanemma and T. emma (Orthoptera: Gryllidae), and larvae of the fruit fly, Drosophila melanogaster (Diptera: Drosophilidae). When analyzed by liquid chromatography/mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF), the gut contents of both crickets had nearly identical FAA composition, the major FAAs comprising N-linolenoyl-L-glutamic acid and N-linoleoyl-L-glutamic acid. There were also two previously uncharacterized FAAs that were thought to be hydroxylated derivatives of these glutamic acid conjugates, based on their observed fragmentation patterns. In addition to these four FAAs containing glutamic acid, N-linolenoyl-L-glutamine and a small amount of volicitin were detected. In D. melanogaster, N-linolenoyl-L-glutamic acid and N-linoleoyl-L-glutamic acid were the major FAAs found in larval extracts, while hydroxylated glutamic acid conjugates, volicitin and N-linolenoyl-L-glutamine, were detected as trace components. Although these FAAs were not found in ten of the insects studied here, their identification in two additional orders of insects suggests that FAAs are more common than previously reported and may have physiological roles in a wide range of insects besides caterpillars.

A new steroid glycoside and furochromones from Cyperus rotundus L.

Further phytochemical investigation of the aerial parts of Cyperus rotundus L. afforded a new steroid glycoside named sitosteryl (6′-hentriacontanoyl)-β-D-galactopyranoside (4) in addition to three furochromones, khellin (2), visnagin (3) and ammiol (9). Furthermore, benzo-α-pyrone (coumarin) (1), salicylic acid (5), caffeic acid (6), protocatechuic acid (7), p-coumaric acid (8), tricin (10) and isorhamnetin (11) were isolated. The structures of these compounds were established by spectroscopic methods. The isolated furochromones were tested for insect antifeedant activity against larvae Spodoptera littoralis when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay. Also, visnagin, khellin and sitosteryl (6′-hentriacontanoyl)-β-D-galactopyranoside showed strong cytotoxic activity against L5178y mouse lymphoma cells and were also active in the brine shrimp lethality test.