bluuebunny/crossref_metadata_2025 huggingface dataset:
Ballooning activity of Chilo partellus larvae in relation to size of mother, egg batches, eggs and larvae and age of mother
Authors: Berger Amelie
Published: April 2011

The ballooning behaviour of first instar larvae of Chilo partellus (Swinhoe) (Lepidoptera:Pyralidae) was studied using a wind tunnel. About 55% of the newly hatched larvae left the young maize plants on silk threads within two hours after their release. No significant correlations were found between spinning‐off activity and mother weight, egg weight and number of eggs per batch. Ballooning and non‐ballooning larvae were of the same size. Time of oviposition did not influence the ballooning behaviour. There was significant variation in spinning‐off activity between offspring from different individual females, however, which suggests that maternal factors other than those measured play an important role in larval dispersal.

Influence de la taille et de l'âge de la mère, des tallies des ooplaques, des oeufs et des chenilles sur l'activité aérostatique des chenilles de Chilo partellus.

Le comportement aérostatique des chenilles néonates de C.*** partellus a été étudié dans un tunnel à vent. Environ 55% des chenilles néonates ont quité les jeunes plants de maïs sur des fils de soie, dans les deux heures qui ont suivi leur libération. Aucune corrélation significative n'a été observée entre l'activité de filature et le poids de la mère, le poids de l'oeuf et la taille de l'ooplaque. Les chenilles aérostatiques ou non étaient de même taille. Le date de ponte n'a pas influé sur le comportement aérostatique. Il y avait des différences significatives dans l'activité aérostatiques des chenilles suivant les mères, ce qui suggère que des facteurs maternels, différents de ceux examinés jouent un rôle important dans la dispersion des chenilles.
Antifeedant activity of bisabolangelone and its analogs against larvae of Pieris brassicae
Authors: Benz G. , Abivardi C. , Muckensturm B.
Published: April 2011

Bisabolangelone and three analogs were assayed, under laboratory conditions, for their antifeedant activity against Pieris brassicae L. (Lepidoptera: Pieridae) larvae. The results of dual‐choice studies revealed that the potent antifeedant activity of bisabolangelone is greatly reduced or lost in the analogs. Insecticidal activity observed in the former was not detected either. Further studies using the lower rates of bisabolangelone showed that the absence of a preferable food resulted in a drastic reduction in feeding and growth, and produced high mortality and inhibition of molting. No developmental deformities reported in stored product insects treated with bisabolangelone were observed in P. brassicae during our studies.

Frasshemmende Wirkung von Bisabolangelone und Analogen bei Larven von Pieris brassicae.

Bisabolangelone und drei Analoge wurden unter Laboratoriumsbedingungen auf ihre frasshemmende Wirkung in Raupen von Pieris brassicae L. (Lepidoptera: Pieridae) geprüft. Die Resultate von Zweifach‐Wahlversuchen zeigten, dass sowohl die frasshemmende als auch die insektizide Wirkung von Bisabolangelone in den Analogen stark reduziert ist oder ganz verloren ging. Weitere Untersuchungen mit niedrigen Bisabolangelone‐Dosen zeigten, dass das Fehlen von wohlschmeckender Nahrung zu einer drastischen Reduktion der Nahrungsaufnahme und des Wachstums der Raupen sowie zur Verhinderung der Häutung und zu hoher Mortalität führt. Deformationen, wie sie von bisabolangelonebehandelten Vorratsschädlingen gemeldet wurden, konnten bei P. brassicae nicht beobachtet werden.
Effects of ingestion of some non‐host plant secondary compounds on larvae of Manauca sexta
Authors: Wrubel R. P. , Bernays E. A.
Published: April 2011

Seven non‐host plant secondary compounds were tested for their post‐ingestional effects on larvae of Manduca sexta Johan. The compounds were selected for their range of effects on feeding behavior in short‐term tests: four showed different levels of deterrence while three were not deterrent. Insects were dosed by coating fresh leaves of their food plant (tobacco) with particular compounds at concentrations of 1% dry weight. Only one compound had detrimental effects on larval performance. The results are discussed in the context of the lack of correlation between deterrence and toxicity and the evolution of plant defenses.

Effets de l'ingestion de quelques substances secondaires de plantes non‐hôtes sur les chenilles de Manduca sexta

Les effets qui suivent l'ingestion de 7 produits secondaires de plantes non‐hôtes ont été examinés sur des chenilles de M. sexta. Ces substances avaient été choisies pour la diversité de leurs effets sur le comportement alimentaire lors d'expériences de courte durée: 4 avaient montré des effets dissuasifs variés, 3 n'en avaient pas présenté. On a enduit des feuilles fraiches de leur plante‐hôte (Nicotania tabacum) des différentes substances à raison d'à peu près 1% du poids sec. Seule une substance a réduit les performances des chenilles. Ces résultats ont été discutés en fonction de l'absence de relation entre dissuasion et toxicité dans l'évolution des défenses chez les plantes.
Interactive effect of protein and rutin on larval Heliothis zea and the endoparasitoid Hyposoter exiguae
Authors: Bloem Ken A. , Duffey Sean S.
Published: April 2011

Inhibition of larval growth of Heliothis zea (Boddie) (Lepidoptera: Noctuidae) by the phenolic rutin increased with increasing levels of protein. The strength of the rutin/protein interaction varied depending on the type of protein used. Rutin uptake into the haemolymph of H. zea was independent of dietary protein concentration. Protein and amino acid levels increased in the haemolymph as the level of protein in the diet increased. The addition of rutin to these diets resulted in decreases in haemolymph lipid and protein content and further increases in amino acids. The effect of host diet on growth and development of the parasitoid Hyposoter exiguae (Viereck) (Hymenoptera: Ichneumonidae) was related to the effect of the diet on host larval growth, i.e., diets which stressed the host to the greatest extent had the greatest effect on the parasitoid. Uptake of rutin into the parasitoid was extremely low and was not dose related to the effects of the diets on the parasitoids. The results are discussed relative to the nature of the rutin‐protein interaction, both for the host and parasitoid. Our results point to the need for more attention to be given to the potential interactivity between natural products in describing how plant natural products affect herbivorous insects and mediate effects on other trophic levels.

Interaktiver Effeckt von Protein und Rutin auf Larven von Heliothis zea und auf Larven des Endoparasiten Hyposoter exiguae

Hemmung des Wachstums der Larven von Heliothis zea (Boddie) (Lepidoptera: Noctuidae) durch das Phenol Rutin vergrösserte sich mit steigendem Proteingehalt in der Diät. Das Ausmass der Rutin‐Protein‐Wechselbeziehung hing von der Proteinart ab. Aufnahme von Rutin in die Hämolymphe von H. zea war unabhängig von der Proteinkonzentration in her Diät. Die Protein‐ und Aminosäuregehalte in der Hämolymphe stiegen mit dem Proteingehalt der Diät an. Die Zugabe von Rutin zu diesen Diäten resultierete in geringeren Lipid‐ und Proteingehalten in der Hämolymphe und im weiterem Anstieg des Aminosäurengehaltes in der Hämolymphe. Der Einfluss der Wrtsdiät auf Wachstum und Entwicklung des Parasiten Hyposoter exiguae (Viereck) (Hymenoptera: Ichneumonidae) war abhängig vom Einfluss der Diät auf das Wachstum des Wirtes. Dass heisst, dass diejenigen Diäten, die den Wirt unter den grössten Stress setzten, auch den grössten Einfluss auf den Parasiten hatten. Die Aufnahme von Rutin durch den Parasiten war sehr niedrig und unabhängig von der Dosis. Die Ergebnisse werden diskutiert hinsichtlich der Natur der Rutin‐Protein‐Wechselbeziehung. Unsere Ergbnisse weisen auf die Notwendigkeit hin, potentiellen Wechselwirkungen zwischen natüralichen Pflanzeninhaltsstoffen mehr Aufmerksamkeit zu schenken, um zu verstehen, wie natürliche Pflanzeninhaltsstoffe herbivore Insekten und andere trophische Stufen beeinflussen.
A device for preventing houseflies from copulating
Authors: Keiding Johannes , Rosenkilde Inger
Published: April 2011

The construction and use of a device ‘the virgin chamber', for preventing houseflies, Musca domestica L., from copulating are described. The flies emerge between two horizontal plates kept at a distance of 5 or 4 mm and may be kept in this chamber for 1–3 days before the sexes are separated. The method is regularly used at the Danish Pest Infestation Laboratory for providing unmated flies for selection for resistance to insecticides. Original tests showed that all eggs produced by flies that stayed 1–3 days in the device were infertile, but in recent experiments a small proportion of fertile eggs were found.

Un dispositif pour empêcher les copulations chez Musca domestica

La construction et l'utilisation d'une chambre de virginité, pour empêcher la copulation de M. domestica L. est décrite. Les mouches émergent entre deux plaques horizontales séparées par 4 à 5 mm et sont maintenues dans cette chambre pendant 1 à 3 jours jusqu'à la séparation des sexes. Il s'agit d'une méthode de routine du Laboratoire Danois des Animaux Nuisibles qui fournit des mouches vierges en vue de la sélection pour la résistance aux insecticides. Les tests originels ont montré que tous les œufs pondus par les mouches qui avaient séjourné de 1 à 3 jours dans le dispositif étaient stériles, mais dans des expériences récentes une faible proportion d'œufs ferules a été observée dans quelques tests.
Diapause termination and thermal requirements for postdiapause development in Aphelinus mali at constant and fluctuating temperatures
Authors: Trimble R. M. , Blommers L. H. M. , Helsen H. H. M.
Published: April 2011

Diapause termination under natural and simulated overwintering conditions, the effect of subzero temperature on postdiapause development and the relationship between postdiapause development rate and constant and fluctuating temperatures was studied in a Dutch population of Aphelinus mali Hald. (Hymenoptera: Aphelinidae).

The rate of diapause termination was similar in larvae overwintering under natural and simulated conditions. Most larvae had terminated diapause by the last week of February. Some female larvae may have remained in diapause until the end of March. The exposure of postdiapause larvae to −10 °C for two weeks did not affect their survival or postdiapause development rate.

Postdiapause A. mali larvae could complete development and the adults emerge from their mummified aphid hosts at constant temperatures from 12 to 24 °C. Although some larvae completed postdiapause development at 10 °C, few emerged. The theoretical threshold temperature (to) for postdiapause development was 9.4 °C and the thermal constant (K) 136.4 degree‐days. K was 121.4 and 134.8 for first and 50% emergence, respectively.

The number of heat units accumulating above 9.4 °C to 1st and 50% emergence was similar under constant and fluctuating temperatures.

Fin de la diapause et exigences thermiques pour le développement après la diapause d'Aphelinus mali soumis à des températures constantes ou à des thermopériodes

L'achèvement de la diapause en conditions naturelles ou simulant l'hiver, les effets des températures inférieures à zéro sur le développement après la diapause et les relations entre la vitesse de développement après la diapause et les températures constantes ou en thermopériodes ont été examinés sur des populations néerlandaises d'A. mali (Hymenop.; Aphélinidae).

Les taux d'achèvement de la diapause de larves hivernantes étaient semblables en conditions naturelles ou simulées. La plupart des larves ont terminé leur diapause la dernière semaine de février. Quelques larves femelles sont restées en diapause jusqu'à fin mars. L'exposition pendant 2 semaines des larves sorties de diapause à −10 °C ne compromet pas leur survie ou leur taux de développement après la diapause.

Les larves ayant diapause peuvent terminer leur développement et les adultes émerger des pucerons momifiés aux températures constantes comprises entre 12 et 24 °C. Bien que quelques larves achèvent leur développement à 10 °C, peu émergent. La température seuil théorique de développement après la diapause (to) a été de 9,4 °C et la constante thermique (K), 136,5 degrés‐jours. Pour la première émergence et pour 50% d'émergences, les valeurs de K étaient respectivement: 121,4 et 134,8.

Le nombre d'unités thermiques pour la première émergence et pour 50 % d'émergences était le même à température constante ou avec une thermopériode.
Melanization and encapsulation of eggs and larvae of Epidinocarsis lopezi by its host Phenacoccus manihoti; effects of superparasitism and egg laying patterns
Authors: Giordanengo P. , Nénon J. P.
Published: April 2011

Encapsulation of Epidinocarsis lopezi (De Santis) (Hymenoptera, Encyrtidae) by the cassava mealybug Phenacoccus manihoti Matile‐Ferrero (Homoptera, Pseudococcidae) was studied in the laboratory under controlled conditions (thermohygrometry and photoperiod as close as possible to field conditions): temperature, 26 ± 1 °C; relative humidity, 80 ± 10%; photoperiod, 12 h. Encapsulation began with melanin deposits forming on the parasitoid envelopes at different developmental stages: egg chorion and cuticle of L2 and L3 larvae. It led to the formation of an amorphous capsule from which parasitoids could occasionally escape. Encapsulation affected 26.7% of all parasitoids in solitary parasitism. There was a highly significant increase in the level of encapsulation (83.3%) in superparasitism. Encapsulation was more likely when egg laying occurred in the median body zone of host mealybugs but it was not related either to the sequence of eggs deposited or to the duration of egg laying. These results have significant implications for the assessment of E. lopezi parasitoid efficiency and should be considered in the current biological control program on P. manihoti in Africa.

Mélanisation et encapsulement des œufs et des larves d'Epidinocarsis lopezi par son hôte Phenacoccus manihoti: effets du superparasitisme et des modalités de la ponte

L'encapsulement d'Epidinocarsis lopezi (De Santis) (Hyménoptère, Encyrtidae) par la cochenille du manioc Phenacoccus manihoti Matile‐Ferrero (Homoptère, Pseudococcidae) a été étudié au laboratoire en conditions standardisées de thermohygrométrie et de photopériode aussi proches que possible de celle existant sur le terrain: température: 26 ± 1 °C; hygrométrie relative: 80 ± 10%; photopériode: 12 heures).

Le phénomène débute par un dépôt de mélanine sur les enveloppes du parasitoïde à différents stades de son développement: chorion de l'œuf ou cuticule des larves L2 et L3. Il aboutit à la formation d'une capsule amorphe dont le parasitoïde parvient parfois à s'échapper. L'encapsulement affectant 26,7 % des individus en situation de parasitisme solitaire est très significativement augmenté dans le cas de superparasitisme où ce taux concerne jusqu'à 83,3% des Hyménoptères en développement mais dans ces situations de superparasitisme, un Hyménoptère adulte est toujours obtenu d'une cochenille infestée.

L'encapsulement est par ailleurs favorisé lorsque la ponte du parasitoïde s'effectue dans la région médiane de la cochenille mais ne dépend pas du rang de ponte des œufs et de la durée de la piqûre.

Nos résultats, confirmés par des travaux de terrain au Congo, indiquent qu'un tel taux d'encapsulement a une incidence sur l'efficacité parasitaire d'Epidinocarsis lopezi et qu'il doit être pris en considération dans le progamme de lutte biologique en cours en Afrique contre Phenacoccus manihoti.
Are the oviposition traits of the South India strain of Callosobruchus maculatus maintained by natural selection?
Authors: Mitchell Rodger , Thanthianga Clement
Published: April 2011

The deposition of eggs by this strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) departs from randomness in three ways; eggs are uniformly dispersed, oviposition rates drop when beans begin to carry 2 or more eggs, and there are sharp host preferences. Using random egg placement for the unspecialized condition, these traits are evaluated for their effect on a female's contributions of offspring to the next generation (R0, the net reproductive rate). The major increases in R0 result from females dispersing eggs so uniformly that larval competition is either reduced or eliminated. Females reduce their oviposition rate when the larva from an egg added to a bean is almost certain to die in competitive encounters. Host preferences and larval survival in a host are positively associated with the abundance of the host in South India. The three oviposition traits act together to give and R0 that is 25–50% than that of eggs placed at random. These traits are known to be variable and heritable, hence, the conditions necessary for natural selection are satisfied.

Les particularités de la ponte d'une souche de Callosobruchus maculatus du Sud de l'lnde sontelles maintenues par sélection naturelle?

Le taux partiel de reproduction nette (R0*) dépend de l'espèce de la plante sur laquelle les œufs sont pondus et du nombre de larves entrant dans la graine. La survie larvaire est réduite par 1/(le nombre de larves par graine) parce qu'une seule larve se développe dans une graine. La fécondité n'est pas modifiée par la compétition subie par les larves, la mortalité larvaire a l'effet le plus important sur R0*. Les femelles éliminent ou réduisent la compétition larvaire en dispersant leurs œufs uniformément et font si peu d'erreurs avec une hyperdispersion que l'évolution d'un comportement plus précis n'accroitrait R0* que de 4% au maximum. Des femelles retournant à une distribution des œufs au hasard provoqueraient une réduction de R0* de 25% au moins.

Les légumineuses généralement cultivées dans l'Inde du Sud sont des hôtes acceptables quand elles sont présentées seules. Le choix des femelles entre 2 hôtes élève R0* de 30% ou plus par rapport à une distribution au hasard. Les préférences les plus nettes concernent des combinaisons présentant la plus grande différence de R0*. Les femelles qui hyperdispersent leurs œufs, choisissent leurs hôtes et évitent les pertes par compétition en empêchant que les œufs ne donnent plus de descendants que ne le ferait une ponte au hasard.

Les particularités de la ponte sont variables et héritables. Les lignées se sélectionnent bien, en fonction de la dispersion de leurs œufs sur les graines, de la discrimination des plantes hôtes, et de la modulation de leur taux de ponte. La sélection naturelle maintient ces particularités du comportement d'une façon sédentaire.
Genetic differentiation and speciation in leaf‐mining flies of the genus Phytomyza
Authors: Frey Jürg E. , Latscha Thierry , McKey Doyle B.
Published: April 2011

Population structure is one of the most important factors determining speciation potential. We analyzed the spatial variation in allozyme frequencies of Phytomyza chaerophylli Kalt. (Diptera: Agromyzidae) using Wright's F‐statistics. The degree of interpopulation variation is substantial (FST = 0.092). Variation between local populations separated by only a few kilometers is as high as between populations as far as 1000 kilometers apart, indicating low interpopulation gene flow. The results are supported by ecological studies which revealed that host plant populations of P. chaerophylli, as well as of other, closely related Phytomyza species, are patchily distributed and have a short average life span. Populations of many Phytomyza species are thus mostly small and partly isolated and are prone to frequent extinctions and bottlenecks. Such conditions greatly increase the chance of rare mutations being fixed in new populations which may eventually lead to speciation. It is argued that the ecology and population structure of P. chaerophylli and congeners favor rapid speciation.

Genetische Differenzierung und Speziation bei blattminierenden Fliegen der Gattung Phytomyza

Die Populationsstruktur ist einer der wichtigsten Faktoren, die das Speziationspotential einer Species bestimmen. Wir analysierten die räumliche Variation der Allozymfrequenzen von Phytomyza chaerophylli Kalt. (Diptera: Agromyzidae) nach den Methoden von Wrights F‐Statistik. Der Grad der genetischen Variation zwischen den Populationen ist beträchtlich (FST = 0.092). Die Variation zwischen lokalen, lediglich durch wenige Kilometer voneinander getrennten Populationen ist gleich gross wie zwischen Populationen, die bis zu 1000 Kilometer auseinander liegen. Eine solche Differenzierung deutet auf einen niedrigen Genfluss zwischen den Populationen. Die Ergebnisse der genetischen Analyse werden gestützt durch ökologische Studien, welche zeigten, dass Wirtspflanzenpopulationen von P. chaerophylli und anderen, nah verwandten Phytomyza‐Arten eine inselartige Verbreitung aufweisen und eine verhältnismässig kurze mittlere Lebensdauer haben. Die Populationen von vielen Phytomyza‐Arten sind daher meist klein und teilweise isoliert und unterliegen häufig Ausrottungen und genetischen Flaschenhälsen (‘Bottlenecks’). Solche Bedingungen vergrössern beträchtlich die Chance, seltene Mutationen in neuen Populationen zu fixieren, was unter Umständen zu Speziation führen kann. Wir stellen fest, dass Ökologie und Populationsstruktur von P. chaerophylli und anderen Arten dieses Genus günstige Voraussetzungen für eine schnelle Speziation darstellen.
Mechanisms of resistance in sorghum to head bug, Calocoris angustatus
Authors: Sharma H.C. , Lopez V.F.
Published: April 2011

Cultivar preference/nonpreference for feeding is one of the components of resistance to the sorghum head bug, Calocoris angustatus Lethiery (Hemiptera: Miridae). IS 2761, IS 9692, IS 17610, IS 17618 and IS 17645 were not preferred by the adults of C. angustatus under multi‐ or two‐choice conditions. However, cultivar preference was not evident under no‐choice tests or headcage conditions.

Reduced oviposition is an important component of resistance to head bugs in IS 17645, IS 17610 and IS 17618. Post‐embryonic development was extended by 1–2 days when nymphs were fed on these genotypes. Fifth instar nymphs and adults had lower weights when reared on IS 17610 and IS 9692. Nymphal survival was relatively lower on IS 9692, IS 17610 and IS 17645.

Fourth instar nymphs were relatively less efficient in food utilization when fed on grain of IS 2761 and IS 6984 as compared with the susceptible cultivars CSH 5 and Swarna. Stage of grain development influenced the indices of consumption and utilization of food by head bugs. Consumption index (CI) and growth rate was lower on 20‐day‐old grain of IS 2761 as compared with 12‐day‐old grain.

Déterminisme de la résistance du sorgho à Calocoris angustatus

Les mécanismes de la résistance du sorgho à la punaise C. angustatus ont été examinés au champ et au laboratoire.

Les préférences des adultes ont été examinées avec choix multiples au champ et au laboratoire sur les 5 cultivars relativement moins sensibles (IS 2761, IS 9692, IS 17610, IS 17618, IS 17645) comparés aux hybrides commerciaux très sensibles (CSH 1, CSH 5, CSH 9). Les différences ont été confirmées avec des choix binaires au laboratoire. L'absence de préférence pour un cultivar est une des composantes de la résistance du sorgho à la punaise. Mais l'absence de préférence n'est cependant pas prouvée en cage au champ au par des expériences en olfactomètre sans choix au laboratoire.

La ponte a été étudié sur 8 ‘génotypes’; pendant la saison des pluies de 1983 et sur 6 génotypes pendant la saison des pluies et après celle‐ci en 1983–84. Les résultats montrent que la réduction de la ponte est une composante importante de la résistance sur IS 17645, IS 17610 et IS 17618.

Pour définir le niveau d'antibiose, l'étude du cycle a été menée au laboratoire sur 5 cultivars relativement peu sensibles (IS 2761, IS 9692, IS 17610, IS 176618, IS 17645) et 3 sensibles (CSH 1, CSH 5, CSH 9). Le développement post‐embryonnaire est prolongé d'un jour au deux quand les larves sont élevées sur grains laiteux de IS 17610 ou IS 17645. Les larves de 5e stade et les adultes ont des poids plus faibles sur IS 17610 et IS 9692.

Les indices de consommation et d'utilisation des aliments ont été calculés pour IS 2761, IS 6984, CSH 5 et Swarna; l'utilisation de grains de IS 2761 et IS 69884, comparée aux grains des cultivars CSH 5 et Swarna, est relativement moins efficace. C1 et GR sont plus faibles sur grains d'IS 2761 de 20 jours que de 12 jours.
The avoidance of diploid drones in closed population honeybee breeding
Authors: Atkinson J. H.
Published: April 2011

Honeybee breeding systems dependent on identification of the sex‐determining alleles need to minimize the number of those alleles. A 4‐allele system is proposed.
Influence of olfactory stimulants on resistance/susceptibility of pearl millet, Pennisetum americanum to the rice weevil, Sitophilus oryzae
Authors: Seifelnasr Y. E.
Published: April 2011

The orientation responses of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) as influenced by the olfactory stimulants emanating from either resistant or susceptible pearl millet, Pennisetum americanum, kernels were studied using a Y‐tube olfactometer. The rice weevils were more attracted towards odours from millet grains than to blank controls and to susceptible entries more than to resistant entries, in general. However, there were exceptions. Odours from some resistant entries caused statistically the same, or even more positive orientations than those from some susceptible entries, and this suggests that the relative resistance of an entry and its olfactory attractiveness may not be strongly related, or that the resistance to infestation might be influenced by factors other than attractiveness. The partial damage of the millet kernel pericarp by abrasion slightly increased the orientational response of the weevils to odours from some susceptible and some resistant entries alike.
Influence of trap surface on the numbers of insects caught in water traps in brassica crops
Authors: Finch S.
Published: April 2011

The contribution of the various surfaces of a water trap to the trap's overall effectiveness was studied in brassica crops by painting black different parts of fluorescent‐yellow water‐traps. Three pest species, Delia radicum (L.), D. platura (Meig.), and Meligethes aeneus (Fab.)/Meligethes viridescens (Fab.), together with blowflies and syrphids, were caught in large numbers. Each insect responded differently to the yellow/black traps. The numbers of insect caught indicated that the area of trap involved in capturing D. radicum was effectively twice the surface area of the water. Yellow traps for monitoring D. radicum populations could be made more selective by painting the inner wall black, as such traps caught similar numbers of D. radicum to all‐yellow traps but 50% fewer D. platura, Meligethes sp. and blowflies, and 95% fewer syrphids.
Influence of phenolglucosides and trichome density on the distribution of insects herbivores on willows
Authors: Soetens Ph. , Rowell‐Rahier M. , Pasteels J. M.
Published: April 2011

The effects of both trichome density and phenolglucoside content of leaves of 76 willow hybrids (Salix alba × fragilis) were measured to estimate their influence on the distribution of Phratora vitellinae (L.), Plagiodera versicolora Baly (Coleoptera: Chrysomelidae) and Pontania proxima (Lepeletier 1823) (Hymenoptera: Tenthredinidae) in a nursery at Gramont, Belgium.

The willows showed differences in their phenolglucoside content and pilosity of leaves and are classified on these basis into four groups by a clustering method. Correlations and multiple regressions showed that these chemical and physical characteristics are good predictors of the abundance of insects. First, the abundance of larvae of Ph. vitellinae, adults of Pl. versicolora and galls of P. proxima is correlated positively with a high phenolglucoside content and a low pilosity of the leaves. Secondly, the distribution of adults of Ph. vitellinae and of larvae of Pl. versicolora is influenced by neither the chemical nor the physical leaves characteristics studied.
Identifying bird cherry‐oat aphid Rhopalosiphum padi emigrants, alate exules and gynoparae: application of multivariate methods to morphometric and anatomical features
Authors: Simon J. C. , Dedryver C. A. , Pierre J. S.
Published: April 2011

Multivariate analysis methods were used to distinguish between the three female alate morphs of Rhopalosiphum padi (L.) (emigrants, alate exules and gynoparae). Fourteen morphometric descriptors and seven anatomical parameters indicative of their potential fecundity were considered. Three populations or clones from distinct areas were also taken into account.

The three alate morphs were separated with between 93% and 100% success. Some simplified criteria allowing distinction are described, and as an example one of them was applied to R. padi alatae caught in three suction traps.

The reliability of the samples analysed is discussed. Practical use of identification techniques described may have implications for forecasting (e.g. Barley Yellow Dwarf Virus Disease), and for improving knowledge of aphid population biology.

Recherche de critères morphométriques et anatomiques de différenciation des trois formes femelles ailées (émigrants, exules ailés et gynopares) du puceron des céréales Rhopalosiphum padi

Des techniques d'analyse multivariée ont été appliquées sur des données morphométriques et anatomiques obtenues pour les trois formes femelles ailées (émigrants, exules ailés et gynopares) de Rhopalosiphum padi (L.) dans le but de les différencier.

Pour cela des paramètres de la fécondité potentielle (nombre d'ovarioles, nombre d'embryons) et des variables morphologiques (mensurations, nombre de rhinaries) ont été évalués pour chacun des morphes sur des individus de trois populations ou clones d'origines géographiques distinctes (Angleterre, Normandie, Bretagne).

Les analyses factorielles discriminantes réalisées sur ces données nous ont permis de séparer avec un taux de succès compris entre 93% et 100% les individus selon leur morphe. A partir de celles‐ci nous avons pu proposer des critères susceptibles de différencier ces trois formes ailées. Le rapport ARS/TARS2 (longueur de l'article apical du rostre/longueur du deuxième segment du tarse postérieur) semble très bien discriminer les émigrants des exules ailés et a été appliqué sur des ailés de R. padi capturés par deux pièges à succion français et un suisse. La séparation des gynopares des exules ailés est par contre moins simple.

La représentativité de l'échantillon analysé a été discutée. Les possibilités d'application des méthodes d'identification des morphes de R. padi sur les ailés capturés aux pièges à succion ont été envisagées dans le cadre de la prévision des risques d'infection des céréales par le virus de la Jaunisse Nanisante de l'Orge (BYDV) et de l'amélioration des connaissances en Biologie des Populations aphidiennes.
Maintenance and termination of reproductive dormancy in an Australian stink bug, Biprorulus bibax
Authors: James D. G.
Published: April 2011

Reproductive dormancy in female Biprorulus bibax Breddin sampled during March‐October in Southern New South Wales was terminated by exposure to 25 °C under long (15h) and short (10h) photoperiods. 27% of individuals collected during March‐May failed to oviposit under short days. Pre‐oviposition period under short photoperiod was greatest during March‐June (22.4–61.7 d) and shortest during July‐October (4.2–14.4 d). Under long photoperiod it was greatest in April and May (20.1–22.3 d) and shortest during June‐October (4.9–16.6 d). Longevity ranged from 39.8–89.0 d, with longest lived females being collected in June and held under short days. Fecundity ranged from 51.6–164.4 and was greatest in individuals collected in June‐July and held under short days. In females held under long days fecundity was greatest in March and lowest in May. These data indicate that female B. bibax pass the winter in a photoperiodic ally maintained reproductive diapause.
Mechanism of whorl feeding resistance to fall armyworm among converted sorghum accessions
Authors: Diawara M. M. , Wiseman B. R. , Isenhour D. J.
Published: April 2011

Field studies were conducted in 1989 to evaluate selected converted sorghum (Sorghum bicolor [L.] Moench) accessions for resistance to whorl‐stage feeding by larvae of the fall armyworm (Spodoptera frugiperda J. E. Smith) and to determine the mechanism of resistance. The sorghum was infested in the whorl 26 days after planting (DAP) in experiment 1 and 33 DAP in experiment 2. In experiment 1, the plant accessions ‘IS7273C,’ ‘IS7444C,’ ‘IS12573C,’ ‘IS12678C,’ and ‘IS12679C’ were more resistant (rating < 3) to damage by S. frugiperda larvae than the resistant check CIMMYT (CM) 1821 (rating 6.2) at 14 days after infestation (DAI). These genotypes were also more resistant (ratings ≤ 4 at 7 DAI and < 3 at 14 DAI) than the resistant check CM1821 (ratings 5.6 at 7 DAI and 8 at 14 DAI) in experiment 2. The number of larvae that established/plant on IS7273C, IS7444C, IS12573C, or IS12679C was significantly less compared with establishment on the resistant check CM1821 at 14 DAI in experiment 1 and at 7 and 14 DAI in experiment 2. Resistance in IS7273C, IS7444C, IS12573C, and IS12679C was mainly due to their rapid rate of growth which induced a quick change in the plant morphology from the whorl‐ to the panicle‐stage and did not permit a sustained colonization of larvae. This new type of resistance could be referred to as ‘morphological non‐preference’ as apposed to chemical non‐preference where non‐preference is due to plant chemical factors. These genotypes had a significantly shorter cycle than the other sorghum genotypes. Host evasion, a type of pseudoresistance, was the basis for resistance in ‘IS7794C’ and ‘IS7947C’. Tolerance was the major mechanism of resistance in the resistant check CM 1821.
Toxicity of mycotoxins of Fusarium sambucinum for feeding in Galleria mellonella
Authors: Mulè G. , D'Ambrosio A. , Logrieco A. , Bottalico A.
Published: April 2011

Fusarium sambucinum Fuckel showed antifeedant activity towards larvae of Galleria mellonella L. when incorporated into insect diet. The activity appeared mostly due to the concentration of trichothecenes present in the fungal extracts. Diacetoxyscirpenol and neosolaniol showed similar levels of activity and were significant potent antifeedants against larvae at 50 and 100 ppm. On the contrary, enniatin B showed no activity up to 100 ppm.
Aestivo‐hibernal reproductive diapause in Drosophila moriwakii: flight as a controlling factor
Authors: Ichijô N. , Beppu K. , Kimura M. T.
Published: April 2011

Drosophila moriwakii Okada & Kurokawa (Diptera; Drosophilidae) generally has only one generation per year and enters aestivo‐hibernal reproductive diapause in Sapporo, northern Japan, but a small fraction of the population produced a second generation in summer at a place where breeding resources were abundant. In this species, diapause seems to be controlled by flight activity. When flies were cultured in cages in which they were able to fly freely, they entered diapause irrespective of photoperiod, but they did not do so at long daylengths when cultured in small vials in which they were prevented from flying. Furthermore, flies with wings removed did not enter diapause at long daylengths even if they were cultured in the cages.
Acidic precipitation increases egg survival in Neodiprion sertifer
Authors: Heliövaara K. , Väisänen R. , Varama M.
Published: April 2011

The effects of simulated acidic precipitation on the egg viability of the European pine sawfly, Neodiprion sertifer Geoffrey (Hymenoptera: Diprionidae) were studied by spraying egg clusters with a mixture of sulphuric and nitric acid (1:1, pH 2, 3, 4, 5, 6, distilled water, natural precipitation) for a month in April‐May. Egg viability analyses showed that the proportion of hatched first instar larvae increased with increasing acidity. The better survival of sawfly eggs in pine needles in more acidic conditions may be partly due to changes in needle physiology affecting egg mortality. However, when the eggs were reared without needles in Petri‐dishes, the proportion of successfully hatched larvae likewise increased with increasing acidity indicating direct acid‐induced changes in the eggs themselves. Acidic precipitation as a stress factor of the host plant apparently changes population dynamics of pine sawflies and may be an important factor in triggering outbreaks.
Factors affecting Ctenarytaina thysanura oviposition on Boronia megastigma terminal shoots
Authors: Mensah R. K. , Madden J. L.
Published: April 2011

Field observations and experiments showed that the attractiveness or Boronia megastigma terminal shoots for Ctenarytaina thysanura (Hemiptera: Psyllidae) oviposition was effected by the quality and quantity of terminal shoots, relative hardness of the terminal shoot combined with a closed or open architecture of the shoot, nitrogenous fertilizer applications and intraspecific competition between psyllids. Heavy feeding either by nymphal or adult psyllids greatly reduces the attractiveness of terminal shoots for oviposition. This deterrence was associated with the production of honeydew resulting in the development of sooty moulds. When all nymphs had developed to adults, a further 21 days was required for the shoots to be restored to their original condition and suitability for oviposition.
Screenhouse trials on the potential of Nosema marucae for the control of Chilo partellus
Authors: Odindo M. O.
Published: April 2011

Tests were carried out in a screenhouse to determine the potential of a microsporidian pathogen, Nosema marucae (Microspora: Nosematidae), for the control of the spotted stalk borer, Chilo partellus (Lepidoptera: Pyralidae), on sorghum. Foliar application of an aqueous suspension of N. marucae spores on egg batches pasted on the sorghum plants reduced leaf‐damage in plants in the protected plots, and increased the proportion of plants with fully‐ and partially formed heads compared to unsprayed plots. Further, there was less tunnelling and fewer larvae in the sprayed plots. The pathogen also reduced pest infestation and damage to plants when the plots were infested with newly emerged larvae instead of eggs. N. marucae has a potential to control C. partellus.
Labelling the blueberry leaftier, Croesia curvalana with foliar sprays of rubidium chloride
Authors: Polavarapu S. , Lonergan G. C. , Seabrook W. D.
Published: April 2011

The feasibility of labelling blueberry leaftier by rearing the larvae on blueberry plants treated with foliar sprays of rubidium chloride (RbCl) at concentrations of 1000, 5000, 10000 and 20000 ppm were assessed. RbCl sprays above 5000 ppm significantly reduced survivorship to adult stage. The adult longevity, fecundity and mating were not affected when the larvae were reared on foliage treated with 5000 ppm RbCl solution. Reciprocal matings of 5000 ppm treated moths with untreated moths revealed transfer of label above the 0.1 μg Rb/insect threshold level from treated males to untreated females (in 8 out of 13 pairs) and vice versa (in 1 out of 9 pairs). Considerable loss of Rb (56–64%) occurred from the leaves over a 15 day period. All of the moths and pupae collected from the RbCl treated plots in 1989 and 1990 respectively, had a Rb content higher than the threshold level. In a preliminary dispersal study, marked male and female moths were found in sweepnet samples collected 20 and 60 m from the centre of the treated field. Labelled male moths were also captured in pheromone traps arranged in a circle, 40 m from the treated plot.
Chemical ‘generalists' and behavioral ‘specialists‘: a comparison of host finding by Stelidota geminata and Stelidota octomaculata
Authors: Blackmer J. L. , Phelan P. Larry
Published: April 2011

Host orientation by two nitidulid beetles was compared: Stelidota geminata (Say), which is very broad in its' host range, and Stelidota octomaculata (Say), a species whose feeding is restricted primarily to acorns. In a no‐choice assay, both species responded to all food substrates offered and neither showed a significant preference among substrates (except banana versus wood fungi for S. octomaculata), or between aseptic and inoculated treatments; however, S. geminata readily displayed both phototactic flights and host‐orienting flights, whereas S. octomaculata never exhibited phototactic flight and never responded to food odors by flying to the source. Furthermore, when upwind‐walking response was compared, S. octomaculata walked to the source at a rate of 0.16 ± 0.01 cm/s, which was significantly lower than that of S. geminata, with a rate of 0.54 ± 0.02 cm/s. Turning frequency on the way to the source also differed between the two species, whereas distance traveled, number of pauses, and duration of pauses did not differ significantly. We submit that both species represent ‘olfactory generalists’, and that the restricted host range of S. octomaculata compared to S. geminata is not mediated by differences in long‐range response to host odors, but rather is due to differences in other behaviors such as a reduced rate of locomotion, post‐landing behavior, and possibly ecological factors.
The influence of aphids and honeydew on the leaving rate of searching aphid parasitoids from wheat plants
Authors: Budenberg W. J. , Powell W. , Clark S. J.
Published: April 2011

Dispersal cages were used to investigate the effects of aphids and treatment with artificial honeydew on the leaving rate of searching females of the parasitoid Aphidius rhopalosiphi from groups of wheat plants. Parasitoids which flew away from groups of plants placed in the centre of a cage were trapped on the sides and roof of the cage and thus were prevented from returning to the plants. The positions of trapped parasitoids suggested their direction of flight when dispersing from the plants. Parasitoids increased their residence times on groups of plants in the presence of aphids and of artificial honeydew, but the rate of parasitism of the host Sitobion avenae was not raised by the presence of artificial honeydew under the experimental conditions used. The direction of flight taken by the majority of parasitoids suggested that they were leaving the plants in order to locate further plants nearby to continue searching rather than to terminate searching and disperse away from the area. The need to consider plant patch size in studies of parasitoid searching behaviour is stressed.
Identification of compounds from the eggs of Ostrinia nubilalis and Mamestra brassicae having kairomone activity on Trichogramma brassicae
Authors: Renou M. , Nagnan P. , Berthier A. , Durier C.
Published: April 2011

In the presence of an extract of Ostrinia nubilalis or Mamestra brassicae eggs, female Trichogramma brassicae exhibited increased rates of upwind locomotion in the tubes of a linear olfactometer. GC and GC‐MS analyses of O. nubilalis and M. brassicae egg extracts revealed the presence of fatty acids, their ethyl esters, and various hydrocarbons. Exposing the wasps to a mixture of the five main saturated hydrocarbons (heneicosane, tricosane, pentacosane, heptacosane and nonacosane) increased the upwind progression in the olfactometer. Single hydrocarbons elicited reduced or no activity. Ethyl palmitate and palmitic acid were also effective in increasing upwind locomotion. Z11‐14: Ac, the main component of the female sex pheromone of O. nubilalis was inactive, regardless of its concentration. It is concluded that various compounds present on the surface of the O. nubilalis egg masses may play a role in the orientation of T. brassicae to its host.

En présence d'un extrait superficiel d'oeufs d'Ostrinia nubilalis, ou de Mamestra brassicae, les femelles du parasitoïde Trichogramma brassicae présentent une tendance accrue à la remontée du tube dans un olfactomètre linéaire. L'analyse des extraits d'oeufs par chromatographie en phase gazeuse couplée à la spectrométrie de masse révèle la présence d'acides gras, de leurs esters éthyliques, et de divers hydrocarbures. Un mélange des principaux hydrocarbures saturés (hénéicosane, tricosane, pentacosane, heptacosane et nonacosane) déclenche également une remontée plus rapide et plus importante du tube. Chacun de ces hydrocarbures pris isolément présente une activité nulle ou réduite. D'autres constituants des extraits, l'acide palmitique et son ester éthylique, présentent également une certaine activité. En revanche, le Z11‐14: Ac, constituant majoritaire de la phéromone sexuelle d'O. nubilalis, est inactif, quelle que soit la dose utilisée. En conclusion, divers constituants présents à la surface des oeufs de la pyrale du maïs modifient le comportement locomoteur de femelles de T. maïdis et pourraient done jouer un rôle dans l'orientation de ce parasitoïde vers son hôte.
Interactions of Russian wheat aphid, a hymenopterous parasitoid and resistant and susceptible slender wheatgrasses
Authors: Reed D. K. , Kindler S. D. , Springer T. L.
Published: April 2011

Interactions among three trophic levels of resistant and susceptible slenderwheat grasses, Elymus trachycaulum (Link) Goule ex Shinners ex. H.F. Lewis, Russian wheat aphid, Diuraphis noxia (Mordvilko), and a hymenopterous parasitoid were studied in the laboratory and greenhouse. These relationships were compared with a commercial susceptible wheat Triticum aestivum L. variety. Aphids reared on the resistant entries showed significantly lower weights and numbers. Significant reduction of parasitoid mummy weight and adult size was positively correlated with the effects on the aphids. Resistant entries also induced a longer prereproductive period for both the aphids and parasitoids. Numbers of aphids and aphid damage were significantly modified by the addition of parasitoids. Parasitism was higher on plants that did not have leaf rolling. These findings may indicate that antibiosis resistance studied here is not the most desirable because it decreases natural enemy vitality.
Larval dispersal from potential hosts within a population of a generalist herbivore, Choristoneura rosaceana
Authors: Carrière Y.
Published: April 2011

The dispersal behavior of Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) first in star larvae was studied in the laboratory. The objectives were to investigate the proximal factors influencing larval dispersal and to establish whether a correspondence exists between larval host acceptance and performance. A dispersal bioassay was validated by demonstrating the presence of a positive correlation between larval host acceptance in the laboratory and in the field. Larval age and family origin, as well as host species attributes were shown to influence larval dispersal rates. Seasonal changes in host plants slightly changed the rank order of larval host acceptance. Leaf texture and the availability of refuges on host plants seemed to be important factors influencing the rate of larval dispersal. Plant odor appeared to be used by the larvae to locate leaves. Nitrogen content of plant species corresponded to larval dispersal rates, but the cause of this association is unclear. Larval dispersal did not match host suitabilities as measured by larval performance. The relationship between host preference and suitability in the obliquebanded leafroller is discussed in an ecological and evolutionary perspective.