bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary selection in adult Locusta migratoria
Authors: Chyb S. , Simpson S.J.
Published: April 2011

Dietary selection was investigated during the first 15 days of adult life in male and female Locusta migratoria L. Insects were provided with two artificial diets, one containing 10, 20 or 28% protein but no digestible carbohydrate, the other 10, 20 or 28% digestible carbohydrate but no protein. Amounts eaten, detailed feeding patterns and somatic and reproductive growth were measured. Unfortunately the artificial diets did not support female reproductive development. Nevertheless, there was convincing evidence that insects regulated both protein and carbohydrate intake during the somatic growth phase by dietary selection and altered consumption.

La sélection des aliments par Locusta migratoria adulte

La sélection des aliments a été suivie pendant les 15 premiers jours de vie imaginale des mâles et des femelles de Locusta migratoria L. Les insectes recevaient 2 régimes alimentaires, l'un contentant 10, 20 ou 28% de protéines, mais pas de carbohydrates assimilables, l'autre 10, 20 ou 28% de carbohydrates assimilables, mais pas de protéines. Les quantités consommées, le détail de la prise de nourriture, et les croissances somatique et reproductive ont été mesurés. Malheureusement, ces régimes artificiels n'ont pas permis le développement ovarien des femelles. Cependant, il y a des preuves convaincantes que les insectes ont contrôlé leur apport en protéines et en carbohydrates pendant la phase de croissance somatique par une sélection alimentaire et une modification de la consommation.
Queen replacement in the termite Microcerotermes papuanus
Authors: Roisin Yves
Published: April 2011

In experimentally orphaned field nests of Microcerotermes papuanus Holmgren, 1911, large numbers of workers develop into replacement reproductives (ergatoids) in only one moult. The females become functional egg‐layers after approximately two months. Nymphs normally reach the last instars in August‐September; at that time, in the orphaned nests, some nymphs moult to nymphoid replacement reproductives. Over long time periods, these nymphoids completely replace the ergatoids and the females become physogastric. Although time‐efficient, queen replacement seems energetically expensive for the society, suggesting that this process is under weak selective pressure in M. papuanus, compared with sympatric species such as Nasutitermes princeps.

Le remplacement de la reine chez le termite Microcerotermes papuanus

Dans les nids de M. papuanus rendus expérimentalement orphelins, un grand nombre d'ouvriers se transforment, en une seule mue, en sexués de remplacement ergatoïdes. Les femelles se mettent à pondre au bout d'environ deux mois. Les nymphes atteignent normalement leurs derniers stades en août‐septembre. A ce moment, dans les nids orphelins, ccrtaines d'entre elles se différencient en sexués nymphoïdes. Dans les expériences de longue durée, ces nymphoïdes remplacent complètement les ergatoïdes et les femelles dcviennent physogastres. Bien que rapide, le remplacement de la reine paraît coûteux pour la société du fait du grand nombre d'individus, ouvriers el nymphes, impliqués. Ceci suggère que la pression de sélection sur ce phénomène est faible chez M. papuanus, par comparaison avec des espèces sympatriques telles que N. princeps.
Heterospecific larval competition and host discrimination in two species of aphid parasitoids: Aphidius ervi and Aphidius smithi
Authors: McBrien H. , Mackauer M.
Published: April 2011

Females of the solitary aphid parasitoids Aphidius ervi Haliday and A. smithi Sharma & Subba Rao (Hymenoptera: Aphidiidae) discriminated between unparasitized pea aphids and those parasitized by the other species. Oviposition restraint varied with the attack sequence and the length of the interval between successive attacks. The tendency to reject a previously parasitized host increased with interval length; A. smithi females rarely oviposited in aphids that had been parasitized ≥30 h earlier by A. ervi. Early first‐instar larvae of A. ervi physically attacked and killed older A. smithi larvae, and older A. ervi larvae killed younger A. smithi, possibly by physiological suppression. Neither species appeared to have a competitive advantage when their eggs hatched at the same time. The evolution of heterospecific host discrimination in A. ervi and A. smithi is discussed. It is suggested that avoidance of multiparasitism is adaptive for both parasitoid species: for A. smithi because it is the inferior larval competitor, and for A. ervi because immatures develop more slowly in multiparasitized than in initially unparasitized hosts.

Compétition interspécifique et discrimination des hôtes chez deux parasitoïdes de pucerons: Aphidius ervi et A. smithi

Les femelles des parasitoïdes de pucerons: Aphidius ervi Haliday et A. smithi Sharma & Subba Rao (Hyméno. Aphidiidae) distinguent les pucerons du pois sains des parasités par d'autres espèces. La rétention de la ponte dépend de la séquence de l'attaque et du temps écoulé entre des attaques successives. La tendance au rejet d'un puceron précédemment parasité augmente avec l'importance du délai; A. smithi a rarement pondu dans des pucerons qui avaient été parasités ≥ 30 h avant par A. ervi. Les jeunes larves de premier stade de A. ervi ont attaqué physiquement et tué les larves plus âgées de A. smithi, et les larves plus âgées de A. ervi ont tué des larves plus jeunes de A. smithi par élimination physiologique. Aucune espèce ne semble avoir un avantage quand les oeufs ont éclos en même temps. L'évolution de la discrimination interspécifique de l'hôte chez A. ervi et A. smithi est discutée. On estime que la tendance à éviter le multiparasitisme est adaptative chez les 2 espèces: pour A. smithi parce qu'il est dominé dans la compétition larvaire et pour A. ervi parce que les larves se développent plus lentement dans un hôte multiparasité que dans un hôte initialement sain.
Changes in chemoreceptor sensitivity in relation to dietary selection by adult Locusta migratoria
Authors: Simpson C. L. , Chyb S. , Simpson S.J.
Published: April 2011

During somatic growth in adult Locusta migratoria L. there are variations in the responsiveness of chemosensilla on the maxillary palps. Relative changes in chemosensitivity to amino acids and sucrose are consistent with relative changes in protein and carbohydrate ingestion. There is a decline throughout the somatic growth phase in the proportion of sensilla responding to stimulation. In those sensilla which respond, there is a decline in the firing rate to amino acids, while sucrose responsiveness declines to a lesser degree. We suggest that variations in the levels of nutrients in the storage tissues, especially the haemolymph, arising from changes in the demand for protein and carbohydrate for growth, directly or indirectly, influence gustatory sensitivity.

Changements de sensibilité des récepteurs chimiques en relation avec la sélection alimentaire de Locusta migratoria adultes

Pendant la croissance de L. migratoria L. les réactions aux acides aminés et aux sucres des sensilles chimiques des palpes maxillaires changent. Ces changements relatifs de la sensibilité chimique à ces deux aliments correspondent aux modifications dans l'ingestion de protéines et d'hydrates de carbone par cet insecte. La diminution de la réponse aux acides aminés est liée à la fois au nombre de sensilles qui réagissent et à leur taux de réaction. La sensibilité des sensilles au sucrose varie moins profondément et implique uniquement des modifications du nombre de sensilles réagissant. Nous suggérons que des variations de la teneur en éléments nutritifs de l'haemolymphe, dues à des modifications de la demande en protéines et en glucides nécessaires à la croissance, influent sur la sensibilité gustative.
Foliar form, colour and surface characteristics influence oviposition behaviour in the cabbage root fly Delia radicum
Authors: Roessingh Peter , Städler Erich
Published: April 2011

The effects of foliar form, colour and surface characteristics on the oviposition behaviour of the cabbage fly were investigated by presenting females with various leaf models made of paper. The models differed in shape, size, colour, surface coating, the presence of 3 dimensional folds and a stem. It was shown that in the presence of host leaf surface extracts physical factors can strongly influence oviposition behaviour. Females laid the most eggs around the base of bright green or yellow models having a stem, vertical folds and covered with a thin layer of paraffin. The vertical folds in the surface increased the chance of a behavioural transition from leaf run to stem run.

Eiablageverhalten der Kohlfliege beeinflusst durch Blatt‐Form, Farbe und Oberflachestructur

Mit Hilfe von Papiermodellen von Kohlblättern wurde der Einfluss von visuellen und mechanischen Eigenschaften des Blattes auf das Eiablageverhalten der kleinen Kohlfliege, Delia radicum, untersucht. Die verwendeten Modelle unterschieden sich in Form, Grösse, Farbe, Oberflächen struktur und Stiel des Blattes. Es wurde gezeigt, dass physikalische Reize zusammen mit den chemischen Stoffe auf der Blattoberfläche stimulierend wirken. Ein natürliches Eiablageverhalten und die stärkste Eiablage wurde durch ein Modell ausgelöst, welches sich durch leuchtend grüne Farbe, Stiel und vertikale Falten und einen Paraffinnüberzug auszeichnete.
The fecundity and oviposition behavior of a South Indian strain of Callosobruchus maculatus
Authors: Thanthianga Clement , Mitchell Rodger
Published: April 2011

The fecundity of the South India strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) is 73 eggs for females developing in 31 days and increases to 94 eggs for females emerging after 41 days. Fed females lay 45–55 more eggs which is the egg‐equivalent of the reserves unfed females had to sacrifice for activity. Competition as a larva did not reduce a female's fecundity. Oviposition is inhibited when females are given 25 or fewer beans for oviposition and it is reversed if females find fresh beans. Oviposition is generally released by beans carrying a below average number of eggs, thus, the eggs are almost uniformly distributed over the beans. Eggs are preferentially placed on the largest egg‐free beans as expected if oviposition is released when a beetle goes from a smaller to a larger bean. The cues regulating host preferences, cowpea > mung » igeonpea » chickpea, are secondary to the cues producing hyperdispersion and the selection of larger beans. We present a model for the oviposition behavior that accounts for the observed responses to species, size, and egg load of oviposition sites.

Fécondité et comportement de ponte de souches de Callosobruchus maculatus du Sud de l'Inde

La fécondité de femelles isolées avec un mâle, sans aliment ni eau, et laissées sans perturbation avec 50 graines au moins sert de fécondité standard. Elle augmente avec le temps de développement de l'œuf à Fadulte de 73 œufs (32 j) à 94 œufs (44 j). La fécondité potentielle, obtenue avec des femelles alimentées sur sucre est de 125 œufs. Des femelles maintenues avec moins de 25 graines réduisent leur fécondité.

Plus de la moitié des femelles distribuent leurs œufs uniformément jusqu'à une densité de 1,5 œuf. L'uniformité peut provenir de l'induction de réactions de ponte par les graines portant moins d'œufs que l'effectif moyen. L'hyperdistribution au dessus des densités de 3 œufs/graine révèle l'aptitude à distinguer les graines avec 3 œufs des graines avec 4 œufs. Il y a moins d'écarts par rapport à l'uniformité (erreurs) avec des graines à surface rugueuse. Des femelles avec 10 graines font moins d'erreurs que des femelles avec 50 ou 100 graines.

Les œufs sont ajoutés aux plus grosses graines sans œufs; ainsi, plus il y a de graines qui portent des œufs, plus le poids des graines avec œufs diminue. Un tel schéma est prévisible si la ponte est induite par des graines plus grosses que les graines rencontrées précédemment. Les femelles présentent un ordre de préférence clair quand elles sont en rapport avec leurs hôtes classiques:

Vigna unguiculata > V. radiata > Cajanus cajan > Cicer arietinum

Les caractères spécifiques de l'hôte, plutôt que la taille ou la texture de la surface servent à la distinction entre les graines d'un même hôte.

Ces résultats expérimentaux peuvent être utilisés pour la modélisation du comportement de ponte d'une femelle.
Significance of water contact as a factor terminating larval diapause in a stem borer, Busseola fusca
Authors: Okuda Takashi
Published: April 2011

Previous studies revealed that diapause larvae of Busseola fusca (Lepidoptera: Noctuidae) began to respond to water and pupated in artificial wet conditions only in late diapause. Experiments are designed to clarify how water is involved in the termination of larval diapause. Neither feeding the larvae on fresh sorghum stems (6 weeks old) nor allowing them to drink water stimulated a break in the larval diapause. Diapause larvae transferred to artificial wet conditions pupated without increase in fresh weight. It is thus concluded that water contact is more significant as a factor terminating diapause in B. fusca than water uptake.

Importance du contact avec l'eau pour l'achèvement de la diapause larvaire chez Busseola fusca

Des études antérieures avaient montré que la diapause des chenilles de B. fusca (Lep., Noctuidae) commence par une réaction à l'eau et qu'elles ne se nymphosent dans des conditions artificiellement humides qu'en fin de diapause. Des expériences ont été conçues pour préciser l'intervention de l'eau dans la terminaison de la diapause. Ni l'alimentation des chenilles sur des tiges fraiches de jeune sorgho (de 6 semaines), ni la possibilité de boire de l'eau n'ont stimulé une rupture de la diapause larvaire. Des chenilles en diapause transférées dans des conditions artificiellement humides se sont nymphosées sans augmentation du poids frais. On en a conclu que le contact avec de l'eau était plus important que l'absorption d'eau comme facteur de fin de diapause chez B. fusca.
Lifecycle of the bruchid beetle Bruchidius uberatus and its predation of Acacia nilotica seeds in a tree savanna in Botswana
Authors: Ernst W. H. O. , Decelle J. E. , Tolsma D. J. , Verweij R. A.
Published: April 2011

The life cycle of the bruchid beetle Bruchidius uberatus in seeds of Acacia nilotica has been investigated under field and laboratory condition. In contrast to the multivoltine populations in the Sudan, in Botswana most beetles of B. uberatus are univoltine. They emerge from the seed and pod in early spring (October to November). Only a small part of the population, which emerge in late summer (February to March) is multivoltine, as confirmed by rearing experiments. The reproductive activity of females is not stimulated by pollen, as found in feeding experiments. Minimum life‐span of adult beetles varies between 4 and 40 days, but it did not differ between univoltine and multivoltine beetles. Other data on life‐history are 22 days for hatching of the fist‐instar larva at a temperature regime of 20/15 °C (day/night) and 15 days at a temperature regime of 32/15 °C and 3 to 11 months for development from larvae to beetle.

During dry storage of seeds B. uberatus can destroy the total amount of stored seeds within a few years. In stored seed pool, host‐specificity of larva is low.

The life cycles of the Botswana population have been discussed in relation to that of the species in the Sudan.

Lebenszyklus des Samenkäfer Bruchidius uberatus und seine Effekte auf Acacia nilotica Samen in einer Baumsavanne in Botswana

Der Lebenszyklus des Samenkäfers Bruchidius uberatus in Samen von Acacia nilotica wurde unter Feld‐ und Laborbedingungen untersucht. Im Gegensatz zu multivoltinen Populationen im Sudan (Peake, 1982) sind die Populationen von B. uberatus in Botswana vor allem univoltin. Adulte Käfer verlassen die Samen von A. nilotica während des Süd‐Frühlings (Oktober/November). Im Spätsommer (Februar/März) geschlüpfte Käfer entstammen multivoltinen Genotypen, wie Züchtungsexperimente gezeigt haben. Die reproduktive Aktivität der Weibchen wird nicht durch die Zufuhr von Pollen oder Zucker stimuliert.

Die Entwicklungsdauer vom Ei bis zum 1. Larvenstadium beträgt 15 Tage bis 52 und 3 bis 11 Monate bis zum adulten Käfer, deren Lebenserwartung unter Laboratoriumbedingungen 4 bis 40 Tage beträgt. Hierbei besteht kein Unterschied zwischen uni‐ und multivoltinen Käfern. Der lange Lebenszyklus in Botswana steht im Gegensatz zu dem 40‐tägigen Lebenszyklus von B. uberatus im Sudan, der offensichtlich durch die Jahrhunderte andauernde Sammlung von Früchten verursacht ist.

Samenvorräte, die zu Forstzwecken längere Zeit aufbewahrt werden, können innerhalb von 5 bis 8 Jahren völlig zerstört werden. Dabei ist die Wirtsspezifität gering. Die Infektion betrifft auch andere Acacia‐Arten, z.B. A. burkei, A. erioloba, A. hebeclada, A. mellifera, A. robusta und A. tortilis. Durch die rasche Zerstörung der Embryoachse haben die Käfer keinen positiven Einfluss auf die Keimung dieser hartschaligen Acacia‐Samen.
Use of systemic insecticide to measure antixenosis to aphids in plant choice experiments
Authors: van Emden H. F. , Vidyasagar P. , Kazemi M. H.
Published: April 2011

Antixenosis in three wheat varieties (Timmo, Moghan 2 and Ommid) to Rhopalosiphum padi (L.) was measured by pairing plants of any two varieties with one plant of each pair treated with a soil drench of the systemic insecticide pirimicarb. Aphids were then allowed access to equivalent leaf areas from the two plants in a leaf cage. The results were compared with similar choice experiments without insecticide. By either technique, the two Iranian varieties (Moghan 2 and Ommid) showed antixenosis in comparison with Timmo. The statistical analysis of the data, using a heterogeneity χ2 test, is described.

Zusammenfassung

Verwendung eines systemischen Insektizids zur Messung von Antixenose gegenüber Blattaüse in Pflanzenwahl‐ Versuchen

Die Antixenose gegenüber Rhopalosiphum padi (L.) in den drei Weizensorten Timmo, Moghan 2 und Ommid, von denen die zwei letzteren Sorten aus dem Iran stammen, wurde unter Verwendung des systemischen Insektizids Pirimicarb gemessen. Jeweils zwei Pflanzen aus verschiedenen Sorten wurden als Paar verwendet (in alien Kombinationen der drei Sorten), pro Paar ein Topf mit Pirimicarb gegossen, und zwanzig Blattlaüse über Blattflächen von beiden Sorten gekäfigt. Ähnliche Versuche wurden auch ohne Insektizid ausgeführt. Beide Methoden zeigten deutliche Antixenose von Moghan 2 und Ommid in Vergleich mit Timmo. Die Insektizidmethode zeigte auch eine Bevorzugung von Moghan 2 gegenüber Ommid, ein Resultat, das mit der schon bekannten relativen Antibiose dieser zwei Sorten übereinstimmte, während sich ohne Insektizid kein solcher Unterschied erwies. Die statistische Analyse solcher Versuche mit einem Insektizid, die eine Modifikation der Berechnung des erwarteten Werts mit dem χ2 Test enthält, ist beschrieben.
Le comportement prédateur de Pachycondyla soror
Authors: Dejean Alain
Published: April 2011

Les Pachycondyla soror sont des prédateurs généralistes. Lorsque l'ouvrière découvreuse a capturé une grosse proie, elle peut, soit la ramener au nid toute seule, soit recruter des congénères pour cette tâche. Après la capture d'un premier termite, les trajets exploratoires sont caractérisés par une géométrie différente: leur sinuosité augmente. Il s'agit là d'une adaptation à la chasse de proies vivant en groupes. D'autre part, ces fourmis distinguent parfaitement les ouvriers des soldats. Face aux soldats, on observe l'apparition d'une posture (antennes et pattes antérieures relevées, hors de portée des mandibules de la proie). Dans quelques cas, deux ouvriers sont ramenés à la fois.

The predatory behaviour of Pachycondyla soror (Formicidae, Ponerinae)

Pachycondyla soror belongs to the Ponerinae, a subfamily of ants considered as primitive. The foraging workers are generalist predators capable of preying on large arthropods using two methods to recruit nestmates. In the hunting area they are capable of recruiting nestmates situated in the surrounding area. The first worker that discovers the prey, either rubs its gaster on the soil around the prey or stings the prey, then returns to the nest to recruit nestmates by simply inciting them to leave the nest. There is group activity during the mastery of the prey and its transport to the nest.

During termite captures, these ants are able to distinguish soldiers from workers. Faced with soldiers they present a posture of ‘prudence’, they throw their antennae back and lift their hind legs, thus avoiding contact of these appendages with the mandibles of the prey. After the capture of the first termite, the workers of P. soror do not immediately return to the nest. They first explore the surrounding zone with particularly sinuous path (area concentrated search). As termites are found generally in groups, this behaviour favours encounter with other individuals. On certain occasions, P. soror workers transport two termites at a time or they recruit nestmates (as mentioned previously). These two observations foreshadow the predatory behaviour of Paltothyreus tarsatus and Megaponera foetens, two other Ponerinae specialized in Termite predation.
Host discrimination and evidence for a host marking pheromone in the almond seed wasp, Eurytoma amygdali
Authors: Kouloussis N. A. , Katsoyannos B. I.
Published: April 2011

Laboratory experiments and observations on the oviposition behaviour of the almond seed wasp Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae) revealed that the females of this species deposit a host‐marking pheromone, immediately after an oviposition, by dragging the tip of their abdomen on the fruit surface. This pheromone enables them to discriminate between the infested and uninfested fruit and to select for oviposition the latter. Its primary function is apparently the prevention of repeated ovipositions in already infested fruit, thus contributing to the optimal utilisation of the available resources for larval development. The responses of individual females to different treatments of almonds, in a series of two‐choice tests, revealed that the pheromone can be perceived by the females on direct contact and, when at high concentrations, also olfactorily from a short distance. The pheromone was present inside the abdomen and thorax of females but not of males, and, although water soluble, could not be entirely removed from heavily infested almonds when rinsed with water. Direct observations revealed that after an average of 3.7 successive visits to pheromone‐bearing almonds, females were induced to walk or, most often, fly away from the experimental set‐up. This suggests that the pheromone may also contribute to the dispersion of the wasps.

Discrimination entre des fruits infectés et non‐infectés et évidence d'une phéronome de marquage de l'hôte chez Eurytoma amygdali

Des expériences de laboratoire et des observations concernant le comportement de ponte de Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae) ont montré que, immédiatement après la ponte, les femelles déposent une phéromone de marquage de l'hôte en trainant le bout de leur abdomen sur la surface de l'amande. Cette phéromone les rends capable de distinguer les fruits infectés des non‐infectés et de sélectionner pour la ponte les derniers. Apparemment, la fonction principale de cette phéromone est la prévention de la répétition des ovipositions dans les fruits déjà infectés et la répartition uniforme des œufs dans les amandes, contribuant ainsi à la meilleure utilisation des ressources disponsibles pour le développement des larves. Des expériences de deux choix entre des fruits de différents traitements ont montré que la phéromone pouvait être perçue par les femelles par le direct contact et, quand elle était à hautes concentrations, par olfaction d'une courte distance. La phéromone était présente dans l'abdomen et dans le thorax des femelles, et bien qu'elle soit soluble à l'eau, elle ne pouvait pas s'éloigner entièrement par lavage des amandes sérieusement infectées à l'eau. Les observations ont démontré qu'après un numéro de 3.7 visites successives sur des amandes portant de la phéromone les femelles s'éloignaient du lieu de ponte en marchant ou, le plus souvant, en s'envolant, ce qui suggère que la phéromone contribue à la dispersion des femelles.
Identification of genotype at the sex‐determining locus in the honeybee
Authors: Atkinson J. H.
Published: April 2011

Genotype at the sex‐determining locus in the honeybee, Apis mellifera, is identified by brood viability levels.
Foraging patterns of two aphid parasitoids, Lysiphlebus testaceipes and Aphidius colemani on banana
Authors: Stadler B. , Völki W.
Published: April 2011

The searching behaviour of two aphid parasitoids, Lysiphlebus testaceipes (Cresson) and Aphidius colemani Viereck (Hymenoptera, Aphidiidae), was analysed. Both species searched banana plants (Musa spec.) infested with the banana aphid Pemalonia nigronervosa Coq. in a different way. L. testaceipes restricted its search to open plant structures and avoided concealed areas. A. colemani partitioned its time spent on the plant between open and concealed areas. This general pattern was independent of aphid colony size and was also observed in the absence of aphids. As a consequence of these searching tactics, the borders of a host patch differed for both parasitoid species. For L. testaceipes, the patch consisted only of aphids feeding on open structures, while it comprised the whole aphid colony for A. colemani. The observed searching patterns resulted in a different exploitation of the aphid colonies.

Das Wirtssuchverhalten zweier Blattlausparasitoide, Lysiphlebus testaceipes und Aphidius colemani, an Bananenpflanzen

Eine Analyse des Suchverhaltens der beiden Blattlausparasitoide Lysiphlebus testaceipes (Cresson) and Aphidius colemani Viereck zeigte, daß beidc Arten Bananenpflanzen (Musa spec.), die von der Bananenblattlaus Pentalonia nigronervosa Coq. befallen waren, auf unterschiedliche Weise absuchten. L. testaceipes beschränkte seine Wirtssuche auf frei zugängliche Pflanzenteile und vermied ein Eindringen in geschützte Pflanzenstrukturen. Dagegen hielt sich A. colemani gleichermaßen häufig auf offenen und in geschützten Pflanzenteilen auf. Dieses generelle Suchmuster war unabängig von der Blattlauskoloniegröße und wurde auch beim Fehlen von Wirten beobachtet. Als Konsequenz aus diesem unterschiedlichen Suchverhalten ergaben sich verschiedene ‘Patchgrenzen’ für beide Parasitoide. Für L. testaceipes bestand der Patch nur aus Blattläusen, die an frei zugänglichen Pflanzenstrukturen saugten, während der Patch für A. colemani alle Blattläuse einschließlich der Tiere umfaßte, die sich in geschützten Pflanzenteilen aufhielten. Damit führte dieses unterschiedliche Suchverhalten beider Parasitoidenarten zu einer unterschiedlichen Ausnutzung der Blattlauskolonien.
Preference of white‐backed planthopper, Sogatella furcifera to different rice varieties
Authors: Mishra N. C. , Misra B. C.
Published: April 2011

Preference studies of the white‐backed planthopper, Sogatella furcifera (Horvath) (Delphacidae: Homoptera) (WBPH) for different growth stages of rice, Oryza sativa L., indicated that WBPH selected its preferred variety for feeding by alighting on the plant and feeding briefly, ‘tasting’ the plant. Differential preference for shelter, food or oviposition by WBPH were observed for different rice varieties and for different stages of a variety. With the advancement of plant age, rice varieties became more unsuitable for feeding and a process progressing more rapidly in resistant varieties. Most of the resistant varieties viz. Pundia, Landi Sarakanti and Ptb‐33, unsuitable for shelter and feeding were usually not preferred for oviposition. However, the tolerant variety Mahia bankoi, though suitable for shelter and feeding was also not preferred for oviposition. Therefore, when screening varieties by only measuring feeding preference sources having tolerance mechanisms of resistance may be overlooked.
Factors affecting entomophilic activity ofNeoaplectana feltiaein mushroom compost
Authors: Tomalak M. , Lipa J. J.
Published: April 2011

The host‐searching ability ofNeoaplectana feltiaeFilipjev (=S. bibionisBovien) (Nematoda: Steinernematidae) in response to larvae of a mushroom fly,Lycoriella solaniWinn. was examined in a mushroom substrate. Individuals ofL. solaniwere less attractive for the parasite than larvae ofGalleria mellonellaL. The nematode juveniles penetrated a 22 cm layer of casing mixture within 2–4 days. In the casing alone nematode effectiveness was better than in mushroom compost or in compost and casing together. In the casing mixture parasite dosages of 20 and 100 juveniles per cm2led to 22% and 45% parasitization ofL. solanirespectively, while allG. mellonellalarvae were parasitized at both dosages. The prevalence of nematode infection depended on the content of water in the mushroom substrate. The highestN. feltiaeinfectivity was observed, when the ratio of the dry casing weight to the weight of water content was 1:2.5. The practical aspects of the observed phenomena, essential for the use ofN. feltiaein the protection of commercial mushroom cultivation are discussed.
The effect of colour of the substrate on the landing and oviposition behaviour of the cabbage root fly
Authors: Košťtál V.
Published: April 2011

Field and laboratory experiments were made in order to understand the relation between the spectral characteristic of a substrate and its attractiveness for Delia radicum (L.) (Diptera: Anthomyiidae) flies to land or oviposit. Landing females preferred substrates with high reflectance of green and particularly of yellow wavelengths, but substrates with a high proportion of the blue and green reflectance simultaneously (light blue and white) were also very attractive. Unattractive substrates had either low reflectance across the whole insect‐visible spectrum (dark blue) or increased reflectance only in orange or red region of the spectrum (red) or a large proportion of UV reflectance (aluminium). Landing males were most attracted to the substrates with the highest total reflection. Oviposition attractiveness of a substrate grew with an increase in the proportion of reflectance in the blue and a decrease in the green regions of the spectrum. In addition, the oviposition attractiveness increased with increasing total reflection and contrast with the background, and decreased with a high proportion of UV reflectance.
Genetic variation among apple and hawthorn host races of Rhagoletis pomonella across an ecological transition zone in the Mid‐Western United States
Authors: Feder J. L. , Bush G. L.
Published: April 2011

In previous studies, we have shown that apple and hawthorn populations of Rhagoletis pomonella (Diptera: Tephritidae) represent partially reproductively isolated and genetically differentiated host races; a result consistent with predictions of sympatric speciation models. The geographic pattern of allozyme variation for these flies is complex, however, as inter‐host differences are superimposed on latitudinal allele frequency clines within the races. In addition, pronounced allele frequency shifts exist among R. pomonella populations across three major ecological transition zones in the mid‐western United States. This suggests that selection related to environmental heterogeneity is responsible for the allele frequency shifts, but does not rule out secondary contact as an alternative possibility. Resolution of this issue is important, because if secondary contact is involved, then we would have to reassess the relationship host race formation has with speciation in the R. pomonella group.

Here, we present results from a detailed genetic analysis of fly populations spanning the deciduous/prairie transition zone near the border between the states of Wisconsin and Illinois. Allele frequencies for hawthorn populations within the zone formed ‘spikes’, rather than the expected steps, and these frequency peaks correlated with variation in local ambient temperature conditions. Ambient temperature, and not secondary contact, therefore appears to be an important determinant of the shape of R. pomonella allele frequency clines. Allele frequency heterogeneity was also observed among apple populations, but was less pronounced compared to that for hawthorn flies. This suggests that ambient temperature differentially affects the host races, possibly through differences in the fruiting phenologies of apple and hawthorn trees. Several pairs of linked loci displayed concordant allele frequency changes and were in disequilibrium among both apple and hawthorn populations along the Wisconsin/Illinois transect. Although we do not know the reason for the observed pattern of disequilibrium, site to site variation in levels of inter‐host migration, coupled with selection, seem the most likely explanations. We conclude by discussing how host specific adaptations, such as those associated with ambient temperature, may interact with host recognition traits to drive the sympatric speciation process for R. pomonella group flies.
Evaluation of techniques for monitoring emergence of the banded fruit weevil, Phlyctinus callosus, in deciduous fruit orchards
Authors: Barnes B. N.
Published: April 2011

Four methods of monitoring emergence of the banded fruit weevil, Phlyctinus callosus (Schoenherr) (Coleoptera: Curculionidae), in deciduous fruit orchards were evaluated to develop an accurate and practical system for use by growers. Box emergence traps placed in the drip area of the trees were the most accurate method of detecting the onset of adult emergence in spring. Limb‐jarring and trunk‐bands detected emergence 2 weeks after that by box traps. Cone emergence traps were less sensitive to the onset of emergence than box traps, but more practical, and are judged to be the best method of monitoring the spring emergence of P. callosus adults. The strategic placement of cone traps over weed hosts particularly favoured by P. callosus will increase the accuracy of these traps in detecting the onset of emergence.
Searching behavior and time budgets of the predator Podisus maculiventris
Authors: Wiedenmann R. N. , O'Neil R. J.
Published: April 2011

Searching behavior of the predaceous insect Podisus maculiventris (Say) (Heteroptera: Pentatomidae) was investigated in the laboratory to verify assumptions made in a predator search model. Female predators were placed into an arena containing 30 lima bean plants (Phaseolus lunatus L.), each having five numbered leaflets. Prey were third‐instar larvae of Mexican bean beetle (Epilachna varivestis Mulsant) at two densities. Predators were observed for 4 h periods as they searched the plant canopy. Results showed that predators searched a greater area and for longer at low prey density than at high prey density. Predators apparently searched plants without using cues, did not search areas of the canopy repeatedly after attacks, and spent approximately 1 h handling prey. Predators spent more time resting than searching, and attack rates were negatively correlated with rest time, but were not correlated with search time. Long resting periods by predators may be a result of energy conservation. The implications for using predators such as P. maculiventris against pests in crops are (i) the predators' searching behavior limits the number of prey attacked, and (ii) the predator may be able to persist at low prey densities better than species with different searching behaviors.
Bean tumbling as a control measure for the common bean weevil, Acanthoscelides obtectus
Authors: Quentin M. E. , Spencer J. L. , Miller J. R.
Published: April 2011

Recognizing that it takes Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) larvae over 24 h to bore into a dry red kidney bean {Phaseolus vulgaris L.) and that boring can occur only at particular sites where a bean abuts some other surface, we postulated that this pest might be controlled by periodic tumbling of beans so as to place initiated holes out of register with requisite touching surfaces. Larvae repeatedly forced to initiate holes might die of exhaustion, if not smashed by tumbling beans. Indeed, brief daily tumbling of beans held in half‐filled jars, buckets, and gunny sacks reduced A. obtectus populations by 97% relative to stationary controls. We recommend that small lots of beans can be protected indefinitely from the bean weevil when stored in <75% filled cylinders rolled ca 1 circumference every morning and evening. This control method should be immediately useful, particularly among subsistence families, since the only external input is knowledge. Also, this control principle might be broadly applicable to other bean and grain pests having strict spatial and temporal requirements for seed penetration.
Analysis of orientation behaviour of Tribolium castaneum and T. confusum to synthetic aggregation pheromone
Authors: Obeng‐Ofori D.
Published: April 2011

Adult male T. castaneum (Herbst) and T. confusum (du Val) secretes an aggregation pheromone that is attractive to both sexes. Orientation behaviour of the two Tribolium species responding to different concentrations of synthetic aggregation pheromone in still and moving air was studied in an 2.5 m × 0.4 m olfactometer. Analysis of Tribolium tracks indicated that the aggregation pheromone stimulated the beetles to walk faster at higher concentrations to increase the frequency and magnitude of turning and to decrease track reversal distances and distances between turns. The mean walking speed of both species was lowest at the highest air speed. The behavioural responses of the beetles to the pheromone in still and moving air were similar, indicating chemotaxis as the major orientation mechanism used by both species to locate an odour source. The beetles showed greater orientation efficiency within a discrete pheromone plume than a diffuse plume.
Resistance to the cowpea weevil (Callosobruchus maculatus) larva in pods of cowpea (Vigna unguiculata)
Authors: Kitch L. W. , Shade R. E. , Murdock L. L.
Published: April 2011

Thirty cowpea, Vigna unguiculata (L.) Walpers, cultivars were evaluated as intact pods to determine if any possessed resistance to the cowpea weevil, Callosobruchus maculatus (Fabr.). Pod resistance was measured as pre‐establishment larval mortality (PreM); those larvae dying after egg hatch but before penetrating into the seeds, and as post‐establishment within‐seed mortality (PostM); those larvae dying after penetrating into the seeds. Among the 30 varieties examined, PreM ranged from 57.9% to 99.4% and PostM ranged from 6.7%, to 82.6%. Ten varieties exhibited total intact pod mortality (mortality from egg hatch to adult emergence from the seed) greater than 95%.

Physical measurements were made of several pod and seed characteristics to ascertain whether the observed pod resistance was due to seed factors, pod‐wall factors, or to interactions between the pod and seeds. Although resistance to breakage (from handling plus pod dehiscence) is a necessary characteristic for overall pod protection against C. maculatus; other factors are also important. Among the other pod and seed characteristics measured to identify major resistance factors, seed coat thickness was the one most highly correlated with pod resistance. Our results suggest that interactions between pod‐wall and seed coat characteristics play a large role in pod resistance of cowpeas to C. maculatus.
Patterns of morphometric and allozyme variation in Aedes albopictus
Authors: Kambhampati S. , Rai K. S.
Published: April 2011

A survey of microgeographic variation using morphometric and allozyme analyses was conducted on 19 US populations of Aedes albopictus (Skuse) (Diptera: Culicidae), a mosquito that was recently introduced into the US. There was considerable variation within and among populations both in morphometric traits and allele frequencies. A multivariate discriminant analysis enabled the separation of populations into distinct groups; separation among the populations in the morphometric analysis was incomplete with an average of 70% of the individuals being correctly classified. In the allozyme analysis, the discrimination was complete. The populations from Texas were placed close together in the morphometric analysis, whereas in the allozyme analysis a geographic clustering of populations could not be detected. A test of association between the distance matrices derived from the morphometric and allozyme analyses was statistically nonsignificant. The results are discussed in the context of the colonization of the US by A. albopictus. The possible factors underlying the differences in the patterns of variation derived from morphometric and allozyme analyses are also discussed.
Sulfhydryl‐reagent alteration of soybean resistance to the cabbage looper, Trichoplusia ni
Authors: Neupane F. P. , Norris D. M.
Published: April 2011

The hypothesis that the sulfhydryl reagent, N‐ethylmaleimide, would function as an elicitor of alterable resistance in soybean (Glycine max) plants to Trichoplusia ni herbivory was tested experimentally under greenhouse conditions. This elicitory chemical, which allows receptor thiols to add across its carbon‐carbon double bond, altered the resistance in one or more leaves of plants at one or more intervals after treatment; and thus yielded results supporting the hypothesis. Leaf dipping and soil application were both effective methods of treatment. Results support the interpretation that an elicitor may function in intact plants by altering the integrity of sulfhydryl groups in receptor macromolecules which are also involved in signaling a change in the plant's biosynthesis of characteristic defensive compounds such as phenyl‐propanoids including antifeedant and antibiotic flavonoids. Induced feeding non‐preference by T. ni was highly correlated positively with the amount of glyceollins in the leaf.
Bionomics and population growth statistics of apterous virginoparae of woolly apple aphid, Eriosoma lanigerum, at constant temperatures
Authors: Asante S. K. , Danthanarayana W. , Heatwole H.
Published: April 2011

Development, survival, reproduction and population growth statistics of apterous virginoparae of woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) at constant temperatures of 10, 13, 15, 20, 25, 30 and 32 °C are reported. The developmental times of all life stages were inversely related to temperature ranging from 10 to 30 °C. Span of total development (time from birth to adulthood) decreased from 57.8 days at 10 °C to 11.7 days at 30 °C and increased to 16.8 days at 32 °C. A good linear model fit (R2 > 0.96) between developmental rate and temperature in the range 10–25 °C was observed for all life stages. The lower developmental threshold was estimated at 5.8 °C for instar I, 4.8 °C for instar II, 4.9° for instar III and 4.4 °C for instar IV. The lower temperature threshold for total development was estimated at 5.2 °C. The upper developmental limit was found to be 32 °C. Mean degree‐day accumulations required for completion of instars I, II, III, IV and total development were: 125.6, 51.0, 47.7, 50.7 and 267.6, respectively. Fecundity, larviposition period and adult longevity were reduced with increasing temperature. Net reproductive rate was greatest at 15 °C whereas intrinsic rate of increase peaked at 25 °C. Optimal performance, as measured by fecundity, survival and intrinsic rate of increase, ocurred in the range 13–25 °C.
Variation in biological characteristics and esterase patterns among populations of Bemisia tabaci, and the association of one population with silverleaf symptom induction
Authors: Costa H. S. , Brown J. K.
Published: April 2011

Biological characteristics (oviposition and survival rates) and esterase banding patterns in native PAGE were investigated to evaluate variation among three populations of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae). Reproductive capabilities of whiteflies from cotton (Gossypium hirsutum L.) and pumpkin (Cucurbita maxima Duchesne) populations were similar on the three host plant species tested. These populations, which had the same wild‐type field origin, reproduced better on either cotton and pumpkin than on poinsettia (Euphorbia pulcherrima Willdenow). In contrast, poinsettia whiteflies exhibited relatively similar reproductive capabilities for the three host species tested. Pumpkin and cotton whiteflies had similar esterase banding patterns (‘A’ type), while poinsettia whiteflies yielded a different banding pattern (‘B’ type). In transmission studies, whiteflies from cotton or pumpkin sources did not induce silverleaf (SSL) or white stem (WS) symptoms in Cucurbita spp. tested. In contrast, poinsettia whiteflies were associated routinely with SSL and WS symptoms in Cucurbita spp. following colonization by whitefly adults. From these data, it was possible to correlate a specific esterase banding pattern (A or B) with reproductive capabilities and the ability to induce SSL and WS symptoms.
Effect of larval density on development and induction of reproductive diapause in Bruchidius atrolineatus
Authors: Desroches P. , Huignard J.
Published: April 2011

In Bruchidius atrolineatus (Pic), an increase in larval density inside the seed led to a reduction in the survival rate during post‐embryonic development, with only a limited decrease in the weight of adults. A high larval density increased the proportion of adults in reproductive diapause under certain thermoperiodic conditions. Under other conditions that already promote the emergence of a high proportion of diapausing beetles, an increase in larval density had no effect on diapause.

There was no correlation between the larval developmental time and the weights of adults in a strain with a very low incidence of diapause. However, such a correlation was observed when both sexually‐active and diapausing beetles emerged. This correlation was explained by the longer developmental times and lower weights of diapausing beetles.

Influence de la densité larvaire sur le développement et l'induction de la diapause reproductrice chez Bruchidius atrolineatus Pic(Coléoptère, Bruchidae)

Chez Bruchidius atrolineatus, l'accroissement de la densité larvaire à l'intérieur de la graine entraîne une augmentation de la mortalité alors que la réduction de poids des individus à l'émergence est relativement limitée. L'accroissement de la densité larvaire provoque une augmentation du taux d'adultes en diapause reproductrice, dans certaines conditions thermopériodiques. Dans d'autres conditions, permettant l'émergence d'un fort taux d'adultes diapausants, l'effet de la densité larvaire est nul. Lorsque l'on analyse l'effet de la densité chez les individus d'une souche ne présentant pas de phénomène de diapause, il n'y a pas de corrélation entre la durée de développement et le poids des adultes. Par contre, lorsqu'il y a émergence d'adultes sexuellement actifs et diapausants, il existe une corrélation entre la durée de développement et le poids des adultes émergeants. Cette corrélation est due au fait que les adultes diapausants, qui présentent les durées de développement les plus longues, sont ceux qui ont les poids les plus faibles.
Deterrence of oviposition in Dacus oleae by copper hydroxide
Authors: Prophetou‐Athanasiadou D. A. , Tzanakakis M. E. , & D. Myroyannis , Sakas G.
Published: April 2011

Green olives of three varieties were sprayed in the laboratory with 1% copper hydroxide plus 0.1% Agral‐90 in tap water. A few hours and 1 and 2 days later, the treated olives were offered for oviposition to 15–20‐day‐old females of Dacus oleae (Gmelin) (Diptera: Tephritidae), in two‐choice and no‐choice tests lasting 3 h. In all cases, copper hydroxide had a strong oviposition‐deterring effect, while Agral‐90 alone was ineffective.