bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteinases and amylases of larval midgut of Zabrotes subfasciatus reared on cowpea (Vigna unguiculata) seeds
Authors: Lemos F. J. A. , Campos F. A. P. , Silva C. P. , Xavier‐Filho J. 
Published: April 2011

AbstractProteinase and amylase activities in larval midguts of the bruchid beetle Zabrotes subfasciatus (Boh.) (Coleoptera: Bruchidae) reared on cowpea (Vigna unguiculata (L.) Walp.) seeds were investigated. We could detect and isolate a proteolytic activity with a pH optimum of 5.5 (on azo‐casein as substrate) which was activated by thiol reagents and inhibited by several compounds reactive against ‐SH groups. None of the plant protein inhibitors of serine proteinases utilized were effective inhibitors of this activity. This activity has characteristics of a cysteine class proteinase. We could also detect and isolate a proteolytic activity with a pH optimum of 3.5 (on hemoglobin as substrate) which was not influenced by activators or inhibitors of cysteine, serine, or metalloproteinases. This activity was totally inhibited by pepstatin, a specific inhibitor of aspartic proteinases. We conclude that this activity is due to an aspartic class proteinase. We found also that the aspartic class proteolytic activity is higher than the cysteine class proteinase activity in the midguts of Z. subfasciatus. This seems to be contrary to what is found in Callosobruchus maculatus (F.) larvae midguts. An amylolytic activity with the charateristics of an α‐amylase was also detected and isolated.RésuméProtéinases et amylases de l'intestin moyen de larves de Zabrotes subfasciatus élevées sur Vigna unguiculataLes activités protéinase et amylase ont été étudiées sur l'intestin moyen de larves de Zabrotes subfasciatus Boh. (Coléo, Bruchidae), élevées sur graines de Vigna unguiculata Walp. Nous avons pu décelcr et isoler unc activité protéolytique optimale à pH 5,5 (sur substrat d'azo‐caséine) activée par des réactifs thiol et inhibée par plusieurs composés réagissant aux groupements SH. Aucun inhibiteur végétal des sérine‐protéases utilisé n'a inibé efficacement cette activité qui présente les caractéristiques des protéines de la famille des cystéines. Nous avons pu déceler et isoler aussi une activité protéolytique optimale au pH 3,5 (sur hémoglobine comme substrat) qui n'était pas modifiée par les activateurs ou les inhibiteurs de cystéine, de sérine ou de métalloprotéinases. Cette activité était totalement inhibée par la pepstatine, inhibiteur spécifique des protéinases aspartiques. Nous en concluons que l'activité est due à une protéinase de la famille aspartique. Nous avons trouvé aussi que l'activité protéolytique de la famille aspartique était supérieure à l'activité protéinase de la famille cystéine dans l'intestin moyen de Z. subfasciatus. Ceci semble l'inverse de ce qui a été observé dans l'intestin moyen des larves de Callosobruchus maculatus F. (C.P. Silva & al, in litt.). Une activité amylolytique ayant les caractéristiques d'une α‐amylase a aussi été décelée.
Pattern of growth and fat content of somatic and gonadal tissues of virginoparae of the vetch aphid, Megoura viciae
Authors: Brough C. N. , Dixon A. F. G. , Kindlmann P. 
Published: April 2011

AbstractThroughout the development of virginoparous apterae of the vetch aphid, Megoura viciae, the percentage water content remained constant. Over the period from birth to the onset of reproduction the somatic tissues grew logistically and the gonads exponentially. During development the percentage of the weight of an aphid that consisted of gonads increased. The sigmoidal pattern of growth in weight of an aphid reflects the combined growth patterns of the somatic and gonadal components.Large adults had proportionally bigger gonads than small adults. The fat (lipid) content of both the soma and gonads increased during development; in the soma up to the adult moult, and the gonads up to the onset of reproduction.RésuméCaractères de la croissance et de la teneur en corps gras des tissus somatiques et de gonades des virginipares de Medoura viciae.Le pourcentagc en cau reste constant pendant tout le développement des virginipares de Megoura viciae. De la naissance au début de la reproduction, les tissus somatiques croissent logisliquement et les gonades exponentiellement. Le poids relatif des gonades augmente pendant le développement. L'allure sigmoïde de la courbe de croissance reflète la cominaison des types de croissance des tissue somatiques et des gonades.Les gros adultes ont proportionnellement de plus grosses gonades que les petits. La teneur en corps gras augmente dans le soma et les gonades pendant le développement; dans le soma jusqu'à la mue imaginale, dans les gonades jusqu'au début de la reproduction.
Handling time, prey preference, and functional response for Chrysoperla rufilabris in the laboratory
Authors: Nordlund Donald A. , Morrison R.K. 
Published: April 2011

AbstractThe predaceous larvae of Chrysoperla rufilabris (Burmeister) exhibited some success‐motivated searching, particularly when feeding on Heliothis virescens (F.) eggs, but handling time did not decrease with experience. Handling time for H. virescens larvae was more than twice that for eggs. H. virescens larvae were preferred to cotton aphids (Aphis gossypü (F.)) while aphids were preferred to H. virescens eggs. C. rufilabris larvae exhibited a linear functional response to the three prey types tested, over the prey densities tested.RésuméTemps de manipulation, choix des proies et réactions fonctionnelles de Chrysoperla rufilabris au laboratoireC. rufilabris (Burmeister) est commun dans des habitats variés de différentes parties des USA. Les larves sont prédatrices et attaquent presque tous les insectes au corps mou. Sa prospection est orientée quand il s'alimente sur des œufs et les premiers stades d'Heliothis virescens F. mais pas lorsqu'il consomme Aphis gossypii F. Le temps de manipulation par C. rufilabris n'est cependant pas modifié par la consommation antérieure de proies ces types. Il dépend du type de proie: il est plus de 2 fois plus long avec les chenilles d'H. virescens qu'avec ses œufs. Les larves de C. rufilabris sont des prédateurs généralistes ayant des préférences lorsqu'elles ont le choix: les chenilles d'H. virescens sont préférées aux pucerons du coton, et ceux‐ci aux œufs de H. virescens. Elles présentent une réaction fonctionnelle linéaire pour tous les types de proies, à toutes les densités examinées.C. rufilabris constitue un potentiel intéressant pour la lutte biologique avec des interventions inondatrices contre de nombreux insectes nuisibles. Cependant, des mises au point techniques sont nécessaires pour obtenir une production de masse économique et des méthodes de libération dans la nature efficaces.
Effects of natural enemies on the rate of herbivore adaptation to resistant host plants
Authors: Gould F. , Kennedy G.G. , Johnson M.T. 
Published: April 2011

AbstractThe potential of natural enemies to influence the rate of herbivore adaptation to resistance factors in plants is examined using conceptual and mathematical models. Results indicate that natural enemies could increase or decrease the rate of herbivore adaptation. The specific behavioral and physiological effects of a resistance factor on the herbivore, as well as the behavior of the natural enemy, and the population dynamics of the natural enemy/herbivore system are important in assessing the extent to which the natural enemies will affect the rate of herbivore adaptation to a resistance factor. Herbivore adaptation to partial resistance in a host‐plant is generally expected to be slower than adaptation to high levels of resistance, even in the presence of natural enemies, if genetic variance is not limiting.RésuméInfluence des ennemis naturels sur le taux d'adaptation d'herbivores à des plantes‐hôtes résistantesDes modèles conceptuels et mathématiques ont servi à examiner l'influence du potentiel d'ennemisnaturels sur le taux d'adaptation d'herbivores à des facteurs de résistance des plantes. Les résultats montrent que les ennemis naturels peuvent augmenter ou réduire le taux d'adaptation des herbivores. Les effets spécifiques (comportementaux et physiologiques) d'un facteur de résistance sur l'herbivore, aussi bien que le comportement de l'ennemi naturel et la dynamique de population du système ennemi naturel/herbivore permettent de déterminer le niveau de l'effet des ennemis naturels sur le taux d'adaptation de l'herbivore au facteur de résistance. Une adaptation de l'herbivore à une résistance partielle à une plante est généralement envisagée comme plus lente qu'une adaptation à des hauts niveaux de résistance, même en présence d'ennemis naturels, mais il peut y avoir des exceptions.
Polymer webs to prevent virus transmission by aphids in seed potatoes
Authors: Harrewijn P. , den Ouden H. , Piron P.G.M. 
Published: April 2011

AbstractElectrical registration and visual observation of penetration behaviour combined with ELISA‐technique showed that laboratory‐made webs of synthetic fibers were very promising to protect plants against virus infection by aphids. It was demonstrated that stylet penetration by aphids into potato leaves could be prevented by covering plants with these materials. The recent mass production of polypropylene sealed fiber fleeces and polyethylene nettings have made field experiments possible to determine their effect on aphid probing behaviour and virus transmission.Field experiments with potatoes showed that one particular fleece completely protected the plants against virus transmission (PVY and PLRV) and with a second fleece and a netting a small proportion of plants were infected. In uncovered plots up to 25% of plants became infected. A seed potato crop covered with polypropylene fleece which is inspected regularly for damage will be fully protected against virus transmission.RésuméUtilisation de toiles de polymères afin d'empêcher la transmission de virus par les pucerons chez les pommes de terres semencièresDes enregistrements électriques et des observations visuelles du comportement de pénétration, combinés avec l'usage de la technique ELISA, ont montré que l'usage de toiles de fibres synthétiques élaborées au laboratoire était très prometteur pour la protection des plantes contre des infections virales transmises par des aphides. On a pu démontrer que la pénétration du stylet dans des feuilles de pomme de terre pouvait être empèchée en couvrant les plantes avec ces matériaux. La production en masse récente de nappes en fibres de polypropylene soudées et de filets de polyethylène a rendu possibles des expériences de terrain pour déterminer leur effet sur le comportement de sondage des pucerons et sur la transmission des virus.Des essais en plein champ avec des pommes de terre ont montré qu'un type de nappe en particulier protégeait complètement les plantes contre la transmission de virus (PVY en PLRV) et qu'avec un second type de nappe et un filet une petite proportion de plantes était infectée. Dans des parcelles non couvertes la proportion de plantes infectées sx'élevait jusqu'à 25%. Une récolte de pommes de terre semencières couverte d'une nappe de polypropylène régulièrement inspectée afin de remédier aux détériorations éventuelles sera totalement protégée contre la transmission de virus.
A comparison between the amino acid composition of an egg parasitoid wasp and some of its hosts
Authors: Barrett M. , Schmidt J. M. 
Published: April 2011

AbstractAmino acid compositions of the eggs of five lepidopteran hosts for Trichogramma minutum were compared with each other and with a non‐host species, Rhodnius prolixus, in which T. minutum oviposits but does not develop. Host eggs are quite homogeneous, particularly when compared according to groupings of potentially interconvertible amino acids. Combined mole percent values for glycine, serine and alanine were higher in hosts (27.5–29.2 mole%) than in R. prolixus eggs (21.5 mole%), in bovine serum albumin (14.9%), which has been used as a protein source in artificial diets for T. minutum, or in many of the mixtures used in published diets for this species. Since these three amino acids make up 26.3 mole% of the adult amino acid content of T. minutum, their deficiency in diets could require metabolic compensation detrimental to development.Adult T. minutum arising from eggs of Manduca sexta, Choristoneura fumiferana, and Sitotroga cerealella are similar in amino acid composition to each other and, in general, to their hosts. Variability appears greater in hosts than in adult wasp composition, suggesting some interconversion of host amino acids to accommodate inflexible nutritional requirements of T. minutum.In the three host species tested, free amino acids constituted 15.8–19.3% by weight of the amino acid in egg contents. In M. sexta eggs, glycine, serine and alanine together make up 28.4% by weight of the total free amino acid, a much higher proportion than in many published diets. The four free amino acids (isoleucine, leucine, phenylalanine and histidine) reported to be oviposition stimulants in experiments on encapsulated diets are present in sufficient concentrations to induce oviposition in the host species tested and in R. prolixus.S. cerealella egg contents having approximately 1.8 μg amino acid, yield one or rarely two adult T. minutum (1 μg amino acid/insect). In contrast, M. sexta eggs with 94 μg amino acid each yield an average of 10–12 adults (8.2 μg amino acid/insect). This suggests that small hosts are allocated few eggs which can only develop into small adults because of nutrient supply (parasitoid size in metabolically restricted), whereas much larger hosts are allocated proportionately fewer eggs than the former resulting in larger, and presumably more viable and fecund, adults (parasitoid size is established behaviourally).
The effects of temperature and host density on the development and survival of Copidosoma koehleri
Authors: Horne P. A. , Horne J. A. 
Published: April 2011

AbstractDevelopmental rates for Copidosoma koehleri Blanchard (Hymenoptera: Encyrtidae) and its host, Phthorimaea operculella (Zeller), were determined at 10, 15, 23, 27, 29, 32, 34 and 35 °C from host egg to adult. The developmental rates determined for both species showed good fit to mathematical models of insect development. At 15 °C mean emergence of adult C. koehleri was 15 days after P. operculella adults emerged. At 29 °C mean emergence of C. koehleri was only 5 days after that of P. operculella. P. operculella developed at 35 °C, but parasitized larvae, and therefore C. koehleri, did not tolerate temperatures above 32 °C. In the presence of C. koehleri, host survival was low (3%) at low host egg densities, but greater (20%) at higher host densities. Parasitized larvae of P. operculella were less able to compete for food resources, as measured by adult emergence.
A study on mode of antifeedant effects of epilimonol against Leptinotarsa decemlineata
Authors: Liu Yong‐Biao , Alford A. R. , Bentley M. D. 
Published: April 2011

AbstractColorado potato beetle, Leptinotarsa decemlineata (Say), neonate larvae and adults were bioassayed with the antifeedant epilimonol. Three‐day exposure of neonate larvae resulted in increasing delays in development (appearance of 4th instars) corresponding to increasing dosages. At a dosage of 20 μg/cm2, development was delayed by about 40% without other detrimental effects. Mouthpart coating of adult beetles with epilimonol emulsion resulted in significant feeding reductions, while injection of epilimonol into the haemolymph of female adults did not elicit significant feeding reduction or oviposition suppression. The results indicated that epilimonol did not elicit significant internal toxicity, and feeding reductions were most likely exerted by action on chemoreceptors on mouthparts or in the preoral cavity.
Rutin: a phagostimulant for the polyphagous acridid Schistocerca americana
Authors: Bernays E. A. , Howard J. J. , Champagne D. , Estesen B. J. 
Published: April 2011

AbstractRutin was demonstrated to be a phagostimulant for the grasshopper Schistocerca americana across a very wide concentration range. The effect was not maintained over a period of days if the insects had already ingested a large amount, but when individuals were given different concentrations on disks as supplements to their lettuce diet, they tended to self select a moderate quantity on a daily basis. In long term experiments on food utilization and growth rates using artificial diet, no beneficial effects of rutin could be demonstrated. Ingested rutin was absorbed and some of it deposited in the cuticle. Most was excreted as the aglycone quercetin. The possible functional significance of the phagostimulatory effect is discussed.
Influence of endophyte infection, plant age and harvest interval on Rhopalosiphum padi survival and its relation to quantity of N‐formyl and N‐acetyl loline in tall fescue
Authors: Eichenseer H. , Dahlman D. L. , Bush L. P. 
Published: April 2011

AbstractRhopalosiphum padi L. (Homoptera: Aphididae) is sensitive to loline alkaloids present in tall fescue, Festuca arundinacea Shreb., infected with the endophytic fungus, Acremonium coenophialum Morgan‐Jones & Gams. Aphid survival was higher on endophyte‐free plants regardless of plant age after germination or age of regrowth tissue after clipping. Survival of aphids on endophyte‐infected grass was lower on young tissue but increased as plants aged, although it never reached the same level on endophyte‐free plants. Both N‐formyl and N‐acetyl loline increased as uncut or regrowth tissue aged; however, this was influenced by the age of the plant at the initial cut and the clipping frequency. Although even small amounts of loline cause high aphid mortality, the aphids are able to survive on endophyte‐infected plants if the tillers have senescing leaves which contain lower amounts of loline. Preference for senescing leaves may help R. padi avoid plant parts containing high amounts of toxic allelochemicals, thus contributing to higher numbers of aphids on older, endophyte‐infected plants.
>Morphogenesis and cuticular markers during the larval‐pupal transformation of the medfly Ceratitis capitata
Authors: Rabossi A. , Boccaccio G. L. , Wappner P. , Quesada‐Allué L. A. 
Published: April 2011

AbstractChanges in morphology during early metamorphosis of the medfly, Ceratitis capitata (Wied.) (Tephritidae) were correlated with biochemical differentiation events. Protein profiles were studied both in the 3rd instar larval cuticle further transformed into puparium and the newly synthesized pupal cuticle. Beta‐alanine incorporation into the puparium (0–20 h) correlates with concomitant pigmentation (completed by 16 h) and sclerotization phenomena. This early ‘tannification program seems to be followed by deposition of a layer of substances, probably ecdysial fluid remnants, into the puparium. Their deposition ends approximately at +46 h. Simultaneously, pupal cuticle material starts to be deposited. Synthesis and deposition of the main pupal cuticle protein was detected 48 h after pupariation. At that time, eversion of the pupal head occurs. The definitive profile of pupal cuticle proteins was attained at around +72 h together with the establishment of adult body proportions.
Selection for pesticide resistance in Aphytis
Authors: Javier P. A. , Havron A. , Morallo‐Rejesus B. , Rosen D. 
Published: April 2011

AbstractField‐collected populations of Aphytis holoxanthus DeBach (Hymenoptera: Aphelinidae) and of A. lingnanensis Compere were selected for malathion and azinphosmethyl resistance, respectively, utilizing the male selection method.In preliminary experiments, fertility of virgin females was not significantly lower than that of mated females, and the rate of development of their progeny was similar. Males proved more susceptible to pesticides than females, and among them the sons of virgins were more susceptible than the sons of mated females. Some after‐effects of sublethal exposure to pesticides were noted in both species. A mating ratio of 1 selected male: 2.0–2.5 females was optimal. Cold storage of female pupae proved feasible for synchronizing availability.Resistance of A. holoxanthus to malathion was not increased by 25 male selection cycles. Resistance of A. lingnanensis to azinphosmethyl, which had already been improved by mass selection, was further increased by 7 cycles of male selection.The different outcomes of the two projects are discussed in relation to the variability of the original field populations, and the results of male selection are compared with those of mass selection of identical populations.
Explaining differences in flea beetle Phyllotreta cruciferae Goeze densities in simple and mixed broccoli cropping systems as a function of individual behavior
Authors: Garcia M. A. , Altieri M. A. 
Published: April 2011

AbstractDiversification of habitat has proved to be an efficient way to reduce insect pest levels in agroecosystems. Some general theories used to explain this fact, such as the natural enemies and the resource concentration hypotheses, do not always clearly apply because, in many cases, pest individuals and population response seem controlled by more specific insect‐plant interactions. In non replicated plots, we found substantially lower flea beetle densities in mixed broccoli‐Vicia cropping systems compared to broccoli monoculture. These results were consistent with those from controlled experiments reported in the literature. To investigate if beetle behavior was related to such population reduction, the movement behavior of marked individuals of Phyllotreta cruciferae Goeze released in plots composed solely of broccoli plants and of broccoli mixed with Vicia faba or Vicia sativa plants, was followed and analyzed. The mean tenure time of beetles was longer in simple than in mixed cultures. Also, more beetles tended to fly out and leave mixed cultures compared to monoculture. This resulted in faster reduction of artificially introduced flea beetle populations in the mixed systems.Flea beetles landing on cover crop plants spent considerable time entangled in Vicia sativa branches or attempting to reach the upper part of the tall Vicia faba plants from which they could fly away. It is possible that the beetles characteristic movement on these two species of cover crops increased their risk of predation and the time and energy expended before they reached suitable host plants. Nevertheless, it seems that the detected flea beetle emigration rates were more than sufficient to account for the population trends observed.
Analysis of covariance: an alternative to nutritional indices
Authors: Raubenheimer D. , Simpson S. L. 
Published: April 2011

AbstractSome statistical problems are added to the growing list of cautionary tales regarding the use of the conventional, ratio‐based nutritional indices (RCR, RGR, ECI, AD and ECD). Analysis of ratios is based on the, probably unrealistic, assumption of an isometric relationship between denominator and numerator variables. Analysis of covariance (ANCOVA) makes less restrictive assumptions, and additionally provides important information about the data which is lost by using ratio variables. We demonstrate, using computer‐generated data sets, some of the pitfalls of statistical analysis of ratios and illustrate how these may be avoided using ANCOVA. Some possible consequences of such statistical iniquities for biological interpretations are discussed.