Clove Buds Essential Oil: The Impact of Grinding on the Chemical Composition and Its Biological Activities Involved in Consumer's Health Security.

This study is aimed at identifying the chemical composition of the essential oil extracted from the Syzygium aromaticum seeds, as well as investigating its biological activities, insecticide effect, and allelopathic properties. The extraction yield was about 14.3 and 7.14% for grounded and ungrounded seeds, respectively. The GC-MS analysis allowed the identification of 17 heterogeneous compounds, including eugenol (68.7-87.4%), as major compound, cyperene (20.5-7.2%), phenethyl isovalerate (6.4-3.6%), and cis-thujopsene (1.9-0.8%), respectively, for grounded and ungrounded seeds. Concerning the antibacterial activity, the diameter of the inhibition zone reached 35 mm when the essential oil extracted from grounded seeds was applied against Escherichia coli. Regarding the antioxidant activity via the DPPH radical scavenging test, the IC50 varied from 1.2 ± 0.1 to 2.8 ± 0.5 µg/mL. With respect to reducing power, the efficient concentration EC50 ranged from 32 to 50 µg/mL. The essential oil exhibited also an allelopathic effect against seeds of Hyoscyamus niger, as well as an insecticide effect against Sitophilus oryzae with a DL50 value of 252.4 µL/L air. These findings enhance the use of this spice as a natural food preservative and encourage its use in several fields, including pharmaceutical, cosmetics, agriculture, and therapy, that could be a strategic way to guarantee the consumer's health.

Genome-Wide Association Studies (GWAS) for Yield and Weevil Resistance in Sweet potato (Ipomoea batatas (L.) Lam).

KEY MESSAGE: We apply the GWAS to sweet potato genome, and identified the SNPs associated with yield and weevil resistance. The sweet potato (Ipomoea batatas (L.) Lam) is a highly heterozygous, outcrossing, polyploid species, which presents challenges for genetic analysis. Therefore, we considered that genome-wide association studies (GWAS) may be applied to the study of the sweet potato genome. The yield of two sweet potato varieties [Purple Sweet Lord (PSL) and 90IDN-47] was assessed at two locations (Kumamoto and Okinawa prefectures) in Japan in 2013 and the yield scores were used for GWAS. The results showed that there were several single nucleotide polymorphisms (SNP) above the significance thresholds in PSL; two peaks were detected in Kumamoto and Okinawa on the Ib03-3 and Ib01-4 linkage groups of PSL, respectively. As for 90IDN-47, one relatively high peak was detected in Kumamoto on the Ib13-8 linkage group. Interestingly, although high peaks above significance thresholds were detected in Kumamoto and Okinawa in PSL, the peaks were located in different linkage groups. This result suggests that the genetic regions controlling yield may change in response to environmental conditions. Additionally, we investigated the degree of weevil damage to the plants, which is the greatest problem in sweet potato cultivation in Okinawa. In this experiment, no SNPs were identified above the significance thresholds. However, one relatively high peak was found in the 90IDN-47 genotype, which showed resistance to weevils. On the other hand, one relatively high peak was also detected in the PSL genotype, which showed susceptibility to weevils. These results suggest that two regions could affect weevil resistance and may contain the gene(s) controlling weevil resistance.

Biochemical efficacy, molecular docking and inhibitory effect of 2, 3-dimethylmaleic anhydride on insect acetylcholinesterase.

Evolution of resistance among insects to action of pesticides has led to the discovery of several insecticides (neonicotinoids and organophosphates) with new targets in insect nervous system. Present study evaluates the mode of inhibition of acetylchlonesterase (AChE), biochemical efficacy, and molecular docking of 2,3-dimethylmaleic anhydride, against Periplaneta americana and Sitophilus oryzae. The knockdown activity of 2,3-dimethylmaleic anhydride was associated with in vivo inhibition of AChE. At KD99 dosage, the 2,3-dimethylmaleic anhydride showed more than 90% inhibition of AChE activity in test insects. A significant impairment in antioxidant system was observed, characterized by alteration in superoxide dismutase and catalase activities along with increase in reduced glutathione levels. Computational docking programs provided insights in to the possible interaction between 2,3-dimethylmaleic anhydride and AChE of P. americana. Our study reveals that 2,3-dimethylmaeic anhydride elicits toxicity in S. oryzae and P. americana primarily by AChE inhibition along with oxidative stress.

Synergistic Combinations of a Pyrethroid Insecticide and an Emulsifiable Oil Formulation of Beauveria bassiana to Overcome Insecticide Resistance in Listronotus maculicollis (Coleoptera: Curculionidae).

The annual bluegrass weevil, Listronotus maculicollis (Kirby), is a major pest of golf course turf in eastern North America and has become particularly problematic owing to widespread development of insecticide resistance. As an alternative option to manage resistant adult L. maculicollis, we explored combinations of the pyrethroid insecticide bifenthrin with an emulsifiable oil formulation of the entomopathogenic fungus Beauveria bassiana strain GHA (Bb ES). Combinations synergistically enhanced mortality in both insecticide-susceptible and insecticide-resistant L. maculicollis adults in the laboratory when bifenthrin was used at LC50s for each population. To determine the component behind the synergism, technical spores of B. bassiana GHA and the emulsifiable oil carrier in the fungal formulation were tested separately or in combination with bifenthrin. In both separate and combined applications, the emulsifiable oil carrier was responsible for high mortality within 3 d after treatment and interacted synergistically with bifenthrin, whereas fungus-induced mortality started later. Strong synergism was also observed in three field experiments with a relatively resistant L. maculicollis population. Combinations of Bb ES and bifenthrin hold promise as an effective L. maculicollis management tool, particularly of pyrethroid-resistant populations.

Comparative morphometric and chemical analyses of phenotypes of two invasive ambrosia beetles (Euwallacea spp.) in the United States.

The polyphagous shot hole borer (PSHB), Euwallacea sp., was first detected in 2003 in Los Angeles County, California, USA. Recently, this invasive species has become a major pest of many hardwood trees in urban and wildland forests throughout southern California. PSHB is nearly identical in morphology and life history to the tea shot hole borer (TSHB), Euwallacea fornicatus, an invasive pest of hardwoods in Florida, USA and many other parts of the world. However, molecular studies have suggested that the taxa are different species. We conducted morphometric and chemical analyses of the phenotypes of Euwallacea sp. collected in southern California (Los Angeles County) and E. fornicatus collected in Florida (Miami-Dade County). Our analyses indicated that PSHB has 3 larval instars. The third larval instar was separated from the first 2 instars by head capsule width with 0 probability of misclassification. The body length, head width, and pronotal width of PSHB adult males were significantly less than those of females. Head width and pronotal width of female PSHB were significantly less than those of female TSHB. In contrast, body length, and ratio of body length to pronotal width of female PSHB were significantly greater than those of female TSHB. However, females of these 2 species could not be separated completely by these 4 measurements because of the overlapping ranges. Cuticular hydrocarbons detected in both species were exclusively alkanes (i.e., n-alkanes, monomethylalkanes, dimethylalkanes, and trimethylalkanes). Cuticular hydrocarbon profiles of PSHB males and females were similar, but they both differed from that of TSHB females. Cuticular hydrocarbons of PSHB were predominantly internally branched dimethylalkanes with backbones of 31 and 33 carbons, whereas cuticular hydrocarbons of TSHB females were dominated by internally branched monomethylalkanes and dimethylalkanes with backbones of 28 and 29 carbons. Multiple compounds within these classes appear to be diagnostic for PSHB and TSHB, respectively.

Transgenic sugarcane overexpressing CaneCPI-1 negatively affects the growth and development of the sugarcane weevil Sphenophorus levis.

KEY MESSAGE: Transgenic sugarcane expressing CaneCPI-1 exhibits resistance to Sphenophorus levis larvae. Transgenic plants have widely been used to improve resistance against insect attack. Sugarcane is an economically important crop; however, great losses are caused by insect attack. Sphenophorus levis is a sugarcane weevil that digs tunnels in the stem base, leading to the destruction of the crop. This insect is controlled inefficiently by chemical insecticides. Transgenic plants expressing peptidase inhibitors represent an important strategy for impairing insect growth and development. Knowledge of the major peptidase group present in the insect gut is critical when choosing the most effective inhibitor. S. levis larvae use cysteine peptidases as their major digestive enzymes, primarily cathepsin L-like activity. In this study, we developed transgenic sugarcane plants that overexpress sugarcane cysteine peptidase inhibitor 1 (CaneCPI-1) and assessed their potential through feeding bioassays with S. levis larvae. Cystatin overexpression in the transgenic plants was evaluated using semi-quantitative RT-PCR, RT-qPCR, and immunoblot assays. A 50% reduction of the average weight was observed in larvae that fed on transgenic plants in comparison to larvae that fed on non-transgenic plants. In addition, transgenic sugarcane exhibited less damage caused by larval attack than the controls. Our results suggest that the overexpression of CaneCPI-1 in sugarcane is a promising strategy for improving resistance against this insect.

Effect of Chipping and Solarization on Emergence and Boring Activity of a Recently Introduced Ambrosia Beetle (Euwallacea sp., Coleoptera: Curculionidae: Scolytinae) in Southern California.

Polyphagous shot hole borer (Euwallacea sp., Coleoptera: Curculionidae: Scolytinae) has recently invaded southern California. The beetle, along with its associated fungi, Fusarium euwallaceae, Graphium sp., and Acremonium sp., causes branch dieback and tree mortality in a large variety of tree species including avocado (Persea americana Mill.) and box elder (Acer negundo L.). With the spread of the beetle through Los Angeles, Orange, and San Diego Counties in California, there is increasing concern that felled trees and pruned branches infested with polyphagous shot hole borer should receive sanitation treatment to reduce the potential spread of the beetle from the movement of untreated wood. We tested two sanitation methods to reduce beetle populations, chipping with a commercial chipper and solarization by covering logs with clear or black plastic in full sun. Both chipping and solarization decreased beetle emergence and boring activity compared to untreated control logs. Chipping was most effective for chip sizes <5 cm. Solarization was most effective using clear polyethylene sheeting during hot summer months, particularly August, when daily maximum temperatures were ≥35°C. Beetles persisted for 2 mo or more when solarization was applied during the spring or fall.

First record of Otibazo (Coleoptera: Curculionidae: Molytinae) outside of Japan, with description of a new species from Vietnam.

A new species of wingless leaf litter weevil, Otibazo polyphemus sp. n., is described from Tam Dao, northern Vietnam. This is the fourth named species in the genus, with its three other species known only from Japan. Habitus and genitalia of the male holotype are illustrated and DNA barcoding data are provided. 

Effects of Phaseolus vulgaris (Fabaceae) seed coat on the embryonic and larval development of the cowpea weevil Callosobruchus maculatus (Coleoptera: Bruchidae).

Bruchid beetles infest various seeds. The seed coat is the first protective barrier against bruchid infestation. Although non-host seed coats often impair the oviposition, eclosion and survival of the bruchid Callosobruchus maculatus larvae, morphological and biochemical aspects of this phenomenon remain unclear. Here we show that Phaseolus vulgaris (non-host) seed coat reduced C. maculatus female oviposition about 48%, increased 83% the seed penetration time, reduced larval mass and survival about 62 % and 40 % respectively. Interestingly, we found no visible effect on the major events of insect embryogenesis, namely the formation of the cellular blastoderm, germ band extension/retraction, embryo segmentation, appendage formation and dorsal closure. Larvae fed on P. vulgaris seed coat have greater FITC fluorescence signal in the midgut than in the feces, as opposed to what is observed in control larvae fed on Vigna unguiculata. Cysteine protease, α-amylase and α-glucosidase activities were reduced in larvae fed on P. vulgaris natural seed coat. Taken together, our results suggest that although P. vulgaris seed coat does not interfere with C. maculatus embryonic development, food digestion was clearly compromised, impacting larval fitness (e.g. body mass and survivability).

[Influence of fruit size of Camellia meiocarpa on growth of oil tea weevil, Curculio chinensis (Coleoptera: Curculionidae)].

The relationship between mature larval mass of oil tea weevil (Curculio chinensis) and fruit volume of its host plant oil tea (Camellia meiocarpa) was fitted with Logistic equation in order to understand the restriction of host fruit size on large larval growth and development of the weevil. The results showed that the larval mass increased with the increasing host fruit volume, which was in good conformity with the Logistic model. The weevil larval growth followed the principle of diminishing marginal utility, and it could be divided into two periods, the fast-growing period (<3.216 cm3, one larva per fruit; <4.747 cm3, two larvae per fruit ) and the asymptotic growing period (>3.216 cm3, one larva per fruit; >4.747 cm3, two larvae per fruit). The minimum fruit size threshold was 1500 cm3 for one larva per fruit, and 2.539 cm3 for two larvae per fruit. The temporal pattern that the mature larvae exited from their host fruits was established, the number of larvae escaping from their host fruits decreased daily after the fruit collection, and the larval escaping peak largely appeared from 6:00 to 10:00 AM with 43.9% of total escaping number, and especially from 7:00 to 8:00 AM with 21.1% of total escaping number. The bigger the larvae, the earlier exited from their host fruits. The restriction of fruit size on growth and development of oil tea weevil was observed, and it should be a behavioral adaptation strategy to increase the offspring' s fitness for the parental weevil adults to oviposit on the bigger fruits.

Repelência e atividade inseticida de pós vegetais sobre Zabrotes subfasciatus Boheman em feijão-fava armazenado / Repellency and insecticidal activity of plant powders on Zabrotes subfasciatus (Boh. ) on stored lima beans

O objetivo desta pesquisa foi avaliar o potencial inseticida de Piper nigrum L. (pimenta do reino), Ruta graveolens L. (arruda), Laurus nobilis L. (louro), Syzygium aromaticum (L.) Merr. & L.M.Perry (cravo da índia), Chenopodium ambrosioides L. (mastruz), Piper tuberculatum Jaqc. (pimenta de macaco), Tagetes erecta L. (cravo de defunto), Cymbopogon nardus L. (citronela) e Melissa officinalis L. (erva cidreira) sobre Z. subfasciatus Boh. através dos testes de confinamento, onde os insetos foram confinados durante cinco dias em um recipiente contendo dez grãos de feijão-fava com 0,3 g do pó da planta a ser testada, e, com chance de escolha por meio de uma arena circular, os insetos tiveram a possibilidade de escolha entre grãos com os pós e a testemunha, grãos sem pó das plantas. Observou-se que houve plantas que atuaram como inseticida, outras que repeliram o inseto e não causaram a morte, e outras, que além de repelir também mataram os insetos quando em contato (cravo da índia e matruz). Concluímos que: P. nigrum, P. tuberculatum, S. aromaticum e C. ambrosioides são tóxicas à Z. subfasciatus causando-lhes a morte, L. nobilis, T. erecta, e C. nardus não apresentaram efeito tóxico sobre Z. subfasciatus, C. ambrosioides, S. aromaticum, e C. nardus são repelentes à Z. subfasciatus; P. nigrum, P. tuberculatum, e T. erecta são neutras, e que M. officinalis não apresentou nenhum efeito sobre Z. subfasciatus em relação aos parâmetros avaliados.

The purpose of this research was to evaluate the insecticidal potential of Piper nigrum L., Ruta graveolens L., Laurus nobilis L., Syzygium aromaticum Merr. & L.M.Perry., Chenopodium ambrosioides L., Piper tuberculatum Jaqc., Tagetes erecta L., Cymbopogon nardus L. and Melissa officinalis L. against Zabrotes subfasciatus by free choice, in which, by means of a circular arena, insects had a choice, treatments with or without powder and no choice tests, where insects were confined for five days in a container containing ten grains of lima beans with 0.3 g of powder to be tested. It was observed that some plants have killed the insect while others just repelled the insect, causing no harm to it. Also, one of the studied plants repelled and killed the insects (S. aromaticum, C. ambrosioides and P. tuberculatum). We can conclude that: P. nigrum, P. tuberculatum, S. aromaticum e C. ambrosioides are toxic to the Z. subfasciatus, causing its death. L. nobilis, T. erecta e C. nardus do not present any toxic effect over Z. subfasciatus. C. ambrosioides, S. aromaticum e C. nardus are repellent to Z. subfasciatus. P. nigrum, P. tuberculatum e T. erecta are neutral and M. officinalis have presented no effects over Z. subfasciatus in relation to the parameters evaluated.

Aplicabilidad de estadística multivariada para estudios nutricionales: bioensayo con el gorgojo de arroz (Sitophilus oryzae L) / Applicability of Multivariate Statistics for nutritional studies: bioassay rice weevil (Sitophilus oryzae L)

El análisis de componentes principales (PCA), escalamiento multidimensional no-métrico (MDS) y el análisis de similaridad (ANOSIM) son técnicas estadísticas multivariadas, las dos primeras representan gráficamente de manera simultánea las unidades estadísticas y las variables que las caracterizan, evaluando similaridades entre las unidades y correlaciones entre las variables, la última técnica dota de un test estadístico no paramétrico para comparar agrupaciones de las unidades. Este trabajo evaluó la aplicabilidad de estas técnicas para valorar la calidad nutricional de la dieta, utilizando el bioensayo del gorgojo de arroz. Las dietas ensayadas fueron: almidón de maíz; almidón de papa; 5% glucosa; arvejas; ayuno y ayuno con agua. Se estudiaron las variables supervivencia, variación de peso y composición corporal. El PCA y MDS mostraron relaciones positivas de la supervivencia y variación de peso con los parámetros corporales grasa y carbohidratos, siendo mayor para dietas de almidón, similares al control positivo. En el PCA se observaron diferencias en las poblaciones mantenidas con las diferentes dietas; el MDS no distingue claramente entre ellas, aún cuando logra diferenciar la dieta definida por el ayuno de las restantes. Ambos estudios definieron un gradiente del valor nutritivo de las dietas, en el eje de las abscisas. El ANOSIM indicó diferencias significativas (p<0,05) entre grupos de insectos sustentados con estas dietas. Esta prueba refuerza los resultados obtenidos en el PCA y MDS. La aplicación de estas herramientas estadísticas son promisorias para analizar procesos complejos, como la interacción de distintas variables que midan la calidad nutricional de diferentes dietas.

The principal component analysis (PCA), non-metric multidimensional scaling (MDS) and analysis of similarity (ANOSIM) are multivariate statistical techniques that graphically represent numerical measures of several factors and display multiple relationships that may exist between them. In this study, we evaluated the applicability of these techniques to analyze the nutritional quality of diet, using as model, the bioassay rice weevil. The diets tested were: corn starch, potato starch, 5% glucose, peas, starved and starved with water supply. The variables studied were: survival, weight change and body composition. The PCA and MDS showed positive relationships of survival and weight change with body fat and carbohydrate parameters. Fat and carbohydrates were greater in starches diets, similar to the positive control. The PCA showed differences between populations fed with different diets, whereas the MDS showed similarity between diets. Both studies defined a gradient of the nutritive value of diets in the x-axis. The ANOSIM indicate significant (p<0, 05) differences between groups. This test is necessary to support the results obtained in the PCA and MDS. The application of these statistical tools is promising to analyze complex processes such as interaction of differents variables to measure the nutritional quality of diets.

A remarkable leaf mine induced by Tachygonus sp.n. (Coleoptera: Curculionidae: Curculioninae: Rhamphini) on Erythroxylum subsessile (Erythroxylaceae) with a description of the new species / Mina foliar singular induzida por Tachygonus sp. n. (Coleoptera: Curculionidae: Tachygoninae) em Erythroxylum subsessile (Erythroxylaceae) com descrição da nova espécie

In this study, we describe and present original data on the bionomics and ecology of Tachygonus erythroxyli Hespenheide, New Species, on Erythroxylum subsessile (Mart.). Thirty individuals of E. subsessile were analysed every two months, from October, 2006 to October, 2007 at the National Park of Restinga de Jurubatiba (PNRJ) Carapebus, Rio de Janeiro, Brazil. Females of T. erythroxyli lay their eggs singly on the upper surface of the host's leaves. The mine of T. erythroxyli is expanded with three bubbles, each one representing one larval instar. These mines occur throughout the year in at least half of the host plants and are markedly more abundant in summer. We obtained three parasitoid species, making a total of 53% of the rate of parasitism. Cirrospilus sp. (Eulophidae) was the most prevalent and represented 88% of the parasitoids. The great abundance of Tachygonus mines, their high frequency in their host plant, and local monophagy of this leaf miner weevil suggest a close association between T. erythroxyli and Erythroxylum subsessile.

No presente estudo, foram descritos e apresentados os primeiros dados sobre bionomia e ecologia de Tachygonus erythroxyli Hespenheide, New Species, em Erythroxylum subsessile (Mart.). Trinta indivíduos de E. subsessile foram amostrados a cada dois meses, de outubro de 2006 a outubro de 2007, no Parque Nacional da Restinga de Jurubatiba (PNRJ), Carapebus-Rio de Janeiro, Brasil. Fêmeas de T. erythroxyli colocam ovos isolados na face superior das folhas do seu hospedeiro. A mina de T. erythroxyli é do tipo expandida e apresenta um formato de três bolhas, sendo que cada bolha corresponde a um estádio da larva. Essas minas ocorrem ao longo de todo o ano em pelo menos metade das plantas hospedeiras, sendo marcadamente mais abundantes no verão. Foram obtidas três espécies de parasitoides que, juntas, demonstraram uma taxa de parasitismo de 53%. Cirrospilus sp. (Eulophidae) foi a mais abundante e representou 88% dos parasitoides. A grande abundância de minas de Tachygonus, a alta frequência em seu hospedeiro e a monofagia local desse besouro minador de folhas sugere uma forte associação entre T. erythroxyli e Erythroxylum subsessile.

Rearing the maize weevil, Sitophilus zeamais, on an artificial maize-cassava diet.

Dry artificial diet pellets prepared with maize, cassava chips, and amino acid supplements (lysine and methionine) were evaluated for mass culture of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), a highly polyphagous pest of many stored grains. Evaluation was done in the laboratory at temperature 26 ± 2 °C, 60-70% RH, 12:12 L:D photoperiod. The artificial diet was compounded from different proportions of maize (M) variety TZPB-SW-R, cassava (C) variety TMS-2110, and amino acid supplements, and was pelletized into 6 mm diameter pellets on which five pairs of one-day-old S. zeamais were bioassayed. The diet M(9)C(1) (90% M and 10% C) was the most suitable diet with comparatively shorter developmental period (34.8 days) and the highest F(1) emergence of progeny (145.4) compared to the control, M(10)C(0) (100% M and 0% C).

A remarkable leaf mine induced by Tachygonus sp.n. (Coleoptera: Curculionidae: Curculioninae: Rhamphini) on Erythroxylum subsessile (Erythroxylaceae) with a description of the new species.

In this study, we describe and present original data on the bionomics and ecology of Tachygonus erythroxyli Hespenheide, New Species, on Erythroxylum subsessile (Mart.). Thirty individuals of E. subsessile were analysed every two months, from October, 2006 to October, 2007 at the National Park of Restinga de Jurubatiba (PNRJ) Carapebus, Rio de Janeiro, Brazil. Females of T. erythroxyli lay their eggs singly on the upper surface of the host's leaves. The mine of T. erythroxyli is expanded with three bubbles, each one representing one larval instar. These mines occur throughout the year in at least half of the host plants and are markedly more abundant in summer. We obtained three parasitoid species, making a total of 53% of the rate of parasitism. Cirrospilus sp. (Eulophidae) was the most prevalent and represented 88% of the parasitoids. The great abundance of Tachygonus mines, their high frequency in their host plant, and local monophagy of this leaf miner weevil suggest a close association between T. erythroxyli and Erythroxylum subsessile.

Leviserpin: a serine peptidase inhibitor (Serpin) from the Sugarcane Weevil Sphenophorus levis.

Serine peptidase inhibitors (serpins) form a superfamily of proteins covering abroad spectrum of different biological functions. Here we describe the inhibitory characterization of leviserpin, the first serpin from the sugar cane weevil Sphenophorus levis. Leviserpin was able to inhibit bovine trypsin by the formation of the covalent complex serpin-peptidase, demonstrated by SDS-PAGE and mass spectroscopy analysis. We also have determined the cleavage site at the reactive center loop, by the analysis of the polypeptides released from de C-terminus of leviserpin. Moreover we investigated the mRNA expression of leviserpin in different stages of S. levis development. Thus the specificity of leviserpin, in addition with its mRNA coding being transcribed through all lifecycle of the insect, can suggest a possible role in defense mechanism by regulating the action of prophenoloxidase (proPO) activating enzyme.

Practical and theoretical characterization of Inga laurina Kunitz inhibitor on the control of Homalinotus coriaceus.

Digestive endoprotease activities of the coconut palm weevil, Homalinotus coriaceus (Coleoptera: Curculionidae), were characterized based on the ability of gut extracts to hydrolyze specific synthetic substrates, optimal pH, and hydrolysis sensitivity to protease inhibitors. Trypsin-like proteinases were major enzymes for H. coriaceus, with minor activity by chymotrypsin proteinases. More importantly, gut proteinases of H. coriaceus were inhibited by trypsin inhibitor from Inga laurina seeds. In addition, a serine proteinase inhibitor from I. laurina seeds demonstrated significant reduction of growth of H. coriaceus larvae after feeding on inhibitor incorporated artificial diets. Dietary utilization experiments show that 0.05% I. laurina trypsin inhibitor, incorporated into an artificial diet, decreases the consumption rate and fecal production of H. coriaceus larvae. Dietary utilization experiments show that 0.05% I. laurina trypsin inhibitor, incorporated into an artificial diet, decreases the consumption rate and fecal production of H. coriaceus larvae. We have constructed a three-dimensional model of the trypsin inhibitor complexed with trypsin. The model was built based on its comparative homology with soybean trypsin inhibitor. Trypsin inhibitor of I. laurina shows structural features characteristic of the Kunitz type trypsin inhibitor. In summary, these findings contribute to the development of biotechnological tools such as transgenic plants with enhanced resistance to insect pests.

Detection of gamma radiation-induced DNA damage in maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) assessed using the comet assay.

PURPOSE: The Deoxyribonucleic Acid (DNA) Comet assay, being a quick, simple, sensitive, reliable and fairly inexpensive method for measuring DNA strand breaks, has been used to assess DNA damage caused by gamma radiation in developmental stages of maize weevil Sitophilus zeamais Motschulsky. MATERIALS AND METHODS: An analysis of DNA damage following gamma radiation ((60)Cobalt) treatments at a dose of 0.5 and 1.0 kGy (Kilo Gray) has been carried out with cells obtained from the larvae, pupae and adults of S. zeamais. RESULTS: Gamma radiation induced significant damage at DNA level in the experimental larvae, pupae and adults as manifested by increased strand breaks compared to intact cells from non-irradiated ones. Comet assay revealed that tail length and % tail DNA varied significantly for all developmental stages of S. zeamais. CONCLUSIONS: This study suggests that the comet assay would be a potentially useful tool for detecting DNA damage in insect pest control strategies due to its advantages in the requirement of small numbers of cells per sample and sensitivity in detecting low levels of DNA damage.

Insect diets as mixtures: optimization for a polyphagous weevil.

Development or improvement of artificial insect diets can be tedious, convoluted and often under-appreciated. Using n-dimensional mixture designs, we identified a set of response-optimized meridic diets that contain fewer ingredients than the current commercial diet for Diaprepes abbreviatus, a polyphagous weevil pest of the Caribbean and southern U.S. A diet blend optimized to produce maximum adult weight was predicted to produce adult D. abbreviatus that weigh 28% more compared with adults reared on the standard commercial diet. Diet blends that produced greater individual adult weights resulted in lower survival compared with those blends that yielded adults of more modest proportions. In contrast, a simplified high cottonseed meal blend produced smaller adults more similar to field-collected individuals, and produced the greatest number of adults and the greatest biomass at relatively low cost compared with diets that yielded adult weevils of greater weight. We think that many insect-rearing programs would benefit from application of mixture design methods to situations where diet optimization is desired for researcher-selected criteria. This approach is broadly applicable to any problem that can be conceptualized as a mixture problem.

Suitability of five species of stored-product insects as hosts for development and reproduction of the parasitoid Anisopteromalus calandrae (Hymenoptera: Pteromalidae).

We investigated the ability of two populations of Anisopteromalus calandrae (Hymenoptera: Pteromalidae), to parasitize and develop on late instars of five different stored-product insects that typically complete their development inside seeds of grain or legume species or other dry commodity. The host species were the cigarette beetle, Lasioderma serricorne (F.); cowpea weevil, Callosobruchus maculatus (F.); rice weevil, Sitophilus oryzae (L.); lesser grain borer, Rhyzopertha dominica (F.); and Angoumois grain moth, Sitotroga cerealella (Olivier). Experiments were conducted in the laboratory in a no-choice design by using petri dishes (15 by 100 mm) as experimental arenas with 20 host larvae. A. calandrae females from populations originating in Georgia (GA) and Oklahoma (OK) were introduced singly into experimental arenas and allowed to sting and oviposit for 24 h. Parasitism by the OK population was greater than that for the GA population across all hosts. However, no or very low parasitism was found on Angoumois grain moth for either population in this experiment. The highest number of parasitoid progeny was recorded on cowpea weevil (15.9) followed by rice weevil (11.5) and cigarette beetle (10.8) for the OK population. A similar trend was observed in the GA population. The highest proportion of female progeny was produced on cowpea weevil (73.0%) by the OK population. Conversely, a higher proportion of female progeny was produced on rice weevil (64.6%) by the GA population than produced by the OK population. Parasitoid adults were significantly larger and heavier when they developed on cowpea weevil irrespective of parasitoid population. The possible application of these results for biological control of stored-product insects is discussed.