bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of Azolla forms resistant to the water lily aphid, Rhopalosiphum nymphaeaeSusceptibility of Azolla forms to Rhopalosiphum nymphaeae
Authors: Hance Th. , Nibelle D. , Lebrun Ph. , van Impe G. , van Hove C. 
Published: April 2011

AbstractThe least expensive method for controlling the water lily aphid, Rhopalosiphum nymphaeae (Homoptera: Aphididae), would be to select a more resistant variety of Azolla. Therefore the susceptibility of 6 species of Azolla totalling 12 forms, was analysed by the use of aphid survival and cumulative fecundity. For each form, a minimum of 50 to 140 virginoparous females were followed individually from birth to death. Six forms of three species appeared to be totally resistant, as a mortality rate of 100% was recorded after 4 days; thus insects were unable to reach adulthood. For one form, adults were obtained but died within 11 days and fecundity was poor. The other five forms were more susceptible, and significant differences were found in the total number of offspring after one generation.These results show differences in susceptibility between different forms of Azolla, and thus strongly support the possibility of cultivating more resistant varieties.RésuméLe puceron Rhopalosiphum nymphaeae (L.) peut causer des dégâts importants dans les cultures de la fougère aquatique Azolla. Aussi, dans le but de contrôler ce puceron au moindre coût et sans effets secondaires sur l'environnement, l'étude de la sensibilité différentielle de 12 formes appartenant à 6 espèces d'Azolla a été entreprise. Pour chaque forme de la fougère, de 50 à 140 femelles virginopares du puceron ont été observées durant toute leur vie.Sept formes sont apparues comme totalement résistantes. Cent pourcents de mortalité y ont été observés après 4 jours d'expérience. Pour une forme, des pucerons adultes ont été obtenus mais leur fécondité s'est avérée insuffisante pour compenser les 100% de mortalité observés après 11 jours d'expérience. Les cinq autres formes se sont montrées plus sensibles; dans ce cas, des différences entre les effectifs obtenus après une génération ont permis d'établir un classement de sensibilité variétale.L'existence de ces différences de sensibilité au puceron permet d'envisager la sélection de formes plus résistantes et leur utilisation en conditions de cultures.
Uscana lariophaga, egg parasitoid of bruchid beetle storage pests of cowpea in West Africa: the effect of temperature and humidity
Authors: van Huis A. , Arendse P. W. , Schilthuizen M. , Wiegers P. P. , Heering H. , Hulshof M. , Kaashoek N. K. 
Published: April 2011

AbstractThe stored‐product bruchid pests, Callosobruchus maculatus (Fabricius) and Bruchidius atrolineatus (Pic) cause considerable production losses in cowpea in West Africa. Uscana lariophaga Steffan parasitizes the eggs of the bruchids both in the field and in storage. As chemical control of bruchids in traditional granaries is not appropriate for poor farmers, enhancement of the efficacy of the parasitoid by environmental manipulation has been investigated. The effect of temperature on the capacity of U. lariophaga to parasitize eggs has been studied at eleven constant and three fluctuating temperatures within the range 10 to 45 °C. Longevity of the female wasp decreased with increasing temperature. The rate of development increased linearly at temperatures from 17.5 to 35 °C, but decreased from 35 to 40 °C. Mortality of the developing wasp remained below 20% from 20 to 37.5 °C, but outside this range, mortality reached 100% at 15 and at 42.5 °C. Most parasitization occurred at temperatures of 25 and 30 °C. Sex ratio (percentage females) increased with temperature in the high temperature range. The intrinsic rate of increase (rm) for U. lariophaga was highest in the temperature range from 30 to 37.5 °C and was higher than that of C. maculatus at all temperatures. While the rm value of C. maculatus did not vary much at temperatures from 25 to 35 °C, the rm value of the wasp doubled. Relative humidity did not effect longevity, egg‐laying capacity, mortality, development time and sex ratio of the wasps with C. maculatus as host. However, with B. atrolineatus as the host, development time and mortality increased at lower relative humidity levels. The results indicate that temperature is the major regulating factor on the parasitoid. As the type of storage structure and its location (sun or shade) affects the temperature inside the store, ways are being investigated of manipulating the storage environment through temperature regulation to increase the impact of the parasitoid.
Physiological resistance and behavioral avoidance responses to residues of four pesticides by six spider mite populations
Authors: Suiter K. A. , Gould F. 
Published: April 2011

AbstractSix twospotted spider mite populations were assayed for their levels of physiological resistance and behavioral avoidance to residues of four synthetic pesticides. Mortality could not be estimated for bifenthrin and fenvalerate (synthetic pyrethroids) as mites effectively avoided treated surfaces, however significant between‐population differences in mortality were detected for chlordimeform and cyhexatin. Considerable variation in walkoff and spindown behavioral response to sub‐lethal doses of pesticides was observed among populations within compounds, and within populations among compounds. Within‐compound walkoff and spindown behavioral response varied among all mite populations. Few significant between‐compound correlations were significant, indicating that spider mites responded differently to the four pesticides. The hypothesis that physiological resistance is negatively correlated with behavioral avoidance was tested. Of the four possible negative correlations between physiological resistance and behavioral avoidance for chlordimeform and cyhexatin, only the correlation between cyhexatin‐induced mortality and spindown response was significant. Comparisons of physiological resistance and behavioral avoidance of chlordimeform and cyhexatin by specific pairs of populations did not consistently find these two characters to be related. In a related experiment, the magnitude and direction of the correlation between physiological resistance and behavioral avoidance following selection for increased physiological tolerance to cyhexatin was compared in a highly resistant and a susceptible population of the twospotted spider mite. Mortality in the susceptible population at 2 ppm cyhexatin was similar to mortality in the resistant population at 250 ppm after 72 h exposure (ca. 12%). However, at these concentrations, the resistant population exhibited much higher avoidance of the compound through walkoff response.
Regulation of Helicoverpa zea larval behavior by the parasitoid Eucelatoria bryani
Authors: Reitz Stuart R. , Nettles William C. 
Published: April 2011

AbstractThe parasitoid Eucelatoria bryani Sabrosky regulates the larval behavior of its host Helicoverpa zea (Boddie). Parasitized third, fourth and fifth instars burrow into the soil 0.7–3.4 days earlier than unparasitized larvae that normally enter the soil to pupate at the end of the fifth and final larval instar. Parasitized third instars molt once then burrow as fourth instars, one instar earlier than normal. When E. bryani pupariated on the soil surface in the field, none survived to the adult stage. However, E. bryani adults emerged from 49.2% of hosts that had burrowed into the soil. By accelerating the timing of H. zea burrowing behavior and causing host larvae to enter the soil before death, E. bryani ensures its pupariation in an environment with improved protection against natural enemies and lethal temperatures.
Investigations of the host feeding preferences of Sitona weevils found commonly on white clover (Trifolium repens) in the UK
Authors: Murray P.J. , Clements R.O. 
Published: April 2011

AbstractA series of laboratory and field studies were done to evaluate a range of leguminous plant species for their feeding potential by adult weevils of the genus Sitona Germar. (Coleoptera: Curculionidae). Three species of Sitona, S. lineatus L., S. flavescens Marsh. and S. hispidulus F. all of which are found commonly on white clover (Trifolium repens L.) in the UK were offered a range of 11 legume species, T. repens (white clover, cv. Olwen), T. pratense L. (red clover, cv. Marcom), T. fragiferum L. (strawberry clover, cv. Palestine), T. hybridum L. (hybrid clover, cv. Tetra), T. incarnatum L (crimson clover), T. dubium Sibth. (lesser yellow trefoil), Lotus corniculatus L. (birdsfoot‐trefoil, cv. Leo), L. uliginosus Schkuhr. (large birdsfoot‐trefoil), Melilotus alba Desr. (white melilot), Medicago sativa L. (lucerne, cv. Europe) and M. lupulina L. (black medick) in two laboratory experiments. The weevils were offered a choice of these legumes in one experiment whilst in the other they did not have a choice of food material. These legumes were also sown in the field and a number of measurements of damage, together with counts of Sitona spp., were made. In the laboratory S. lineatus and S. hispidulus favoured some of the legumes to a greater or lesser extent than white clover. S. flavescens was more restricted in its feeding than the other two weevil species. In the field study S. lineatus invaded the experimental area quickly and tended to favour Medicago spp. and Melilotus spp. Later in the year S. flavescens dominated the sitona fauna on the experiment, with the exception of aggregations of S. lineatus on M. sativa and M. alba. In a separate screen of 5 varieties of white clover (cvs Donna, Menna, Kersey, Olwen and Grasslands Huia), cv. Olwen appeared to be the most susceptible to sitona attack.
Interactions between panicle size, insect density, and environment for genotypic resistance in sorghum to head bug, Calocoris angustatus
Authors: Sharma H. C. , Lopez V. F. 
Published: April 2011

AbstractStudies were undertaken on interactions between panicle size, insect density, host plant, and the environment for sorghum head bug, Calocoris angustatus Lethiery on five sorghum genotypes in terms of bug population increase, grain damage and loss in grain mass across four panicle sizes (5, 10 or 20 branches/panicle and whole panicle), and three infestation levels (5, 10 and 15 pairs of bugs/panicle). Head bug numbers increased and grain damage decreased with an increase in panicle size in the head bug susceptible cultivars, CSH 1 and CSH 5. However, the increase in bug numbers or decrease in grain damage was not significant in head bug resistant genotypes, IS 17610 and IS 17645. Head bug numbers increased with an increase in infestation level in CSH 1 and CSH 5, however, such an increase was not substantial in IS 17610 and IS 17645. Grain damage was significantly lower in IS 17610 and IS 17645 compared with CSH 1 and CSH 5 across infestation levels. Head bug population increased at a greater rate during the rainy season compared with the dry season. Panicle size and infestation levels accounted for greater variation in grain damage and percentage loss in grain mass during the rainy season than in the dry season. To identify reliable sources of resistance to insects, it is important to study insect host plant‐interactions across panicle sizes (levels of food availability), infestation levels and season
Geographical variation in habitat choice and host suitability in the parasitoid Asobara rufescens
Authors: Kraaijeveld Alex R. , Voet Steven , van Alphen Jacques J. M. 
Published: April 2011

AbstractIn the Netherlands, Asobara rufescens (Förster) (Hymenoptera: Braconidae) is a parasitoid of drosophilid larvae in decaying plant material. In several places in the Mediterranean, parasitoids looking very similar to A. rufescens were collected on fermenting substrates. A hybridization experiment showed that the parasitoids were indeed A. rufescens. In an olfactometer Portuguese A. rufescens do not have a preference for either the odour of yeast or decaying leaves, while their Dutch conspecifics prefer the odour of decaying leaves. The survival probability of Portuguese A. rufescens in Drosophila melanogaster Meigen (Diptera: Drosophilidae), a species typical for fermenting substrates, is much higher than the survival probability of Dutch A. rufescens in this host species.It is hypothesized that decaying plant material may be unsuitable for drosophilid larvae during part of the year in the Mediterranean, forcing A. rufescens there to broaden its microhabitat choice. The use of fermenting substrates brings A. rufescens in contact with its sibling A. tabida Nees, a species typical for fermenting substrates in most of Europe. Portuguese A. rufescens appear to be genetically isolated from A. tabida. In the Netherlands, where the two species occupy different microhabitats, there is only a premating barrier.
Effects of the ecdysteroid agonists RH 5849 an RH 5992, alone and in combination with a juvenile hormone analogue, pyriproxyfen, on larvae ofSpodoptera exigua
Authors: Smagghe Guy , Degheele Danny 
Published: April 2011

AbstractBiological activity assays with RH 5849 and RH 5992 indicated that both compounds affected growth and development of last‐instar larvae ofSpodoptera exigua(Hübner) (Lepidoptera: Noctuidae) in a dose‐dependent manner. Within the first 24 h after treatment by continuously offering leaves dipped in a water solution of ≥ 50 mg/1 RH 5849 and ≥ 0.5 mg/1 RH 5992, symptoms of a prematurely induced larval moult and head capsule apolysis were visible. Intoxicated larvae died shortly afterwards, showing signs of unsuccessful ecdysis. LC50‐values of RH 5849 and RH 5992 for fifth‐instarS. exigualarvae were 110 and 2.5 mg/l, respectively. Pyriproxyfen alone affected the larval stage and disturbed normal metamorphosis. One supernumerary larval instar occurred occasionally. LC50‐value for pyriproxyfen was 1.7 mg/l. Larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, continued to grow until they attained a size and weight about 2–3 times that of the controls. This growth was accompanied by at least one and sometimes two supernumerary moults.Concerning thein vivoimaginal wing disc growth and development, only in larvae treated with 10 and 50 mg/l RH 5849 or 0.5 mg/l RH 5992, tracheole migration was observed earlier than in the controls. When applying 300 mg/l RH 5849 or 3–7 mg/l RH 5992, the discs remained small and no signs of tracheole migration were observed. In larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, tracheole migration was not prematurely induced and a pupal cuticle was produced in the discs of larvae, undergoing a supernumerary moult. No clear signs of evagination were observed.
Predatory behavior of a seed‐eating ant: Brachyponera senaarensis
Authors: Lachaud Jean‐Paul , Déjean Alain 
Published: April 2011

AbstractThe great flexibility of the feeding strategies exhibited by the ponerine ant Brachyponera senaarensis (Mayr) allows it to exploit either seeds or animal prey items as food resources. Predation is generally limited to small prey and is very similar to scavenging behavior. In laboratory conditions, the predatory behavior of B. senaarensis is not different in structure from that known in other carnivorous ants species. The workers forage individually and return to the nest using a series of cues involving light, a chemical graduated marking system near the nest entrance, and memory. During nest‐moving, recruitment by tandem running was observed. However, in colonies where the food supply is regular, workers that discover food do not recruit nestmates, but make repeated trips between the nest and the food source. On the contrary, in starved colonies, the introduction of prey may produce a massive exit of foragers, corresponding to a primitive form of mass recruitment similar to that observed in some other ant species.
Age effects on the insemination rate of Anopheles gambiae s.l. in the laboratory
Authors: Verhoek B. A. , Takken W. 
Published: April 2011

Accepted: December 30, 1993AbstractAge effects on the insemination rate of the Galisua strain of Anopheles gambiae s.s. (Diptera: Culicidae) and of the Nyanza strain of An. arabiensis were investigated in the laboratory. Batches of 7‐day old males and females were kept together for 24 h with batches of mosquitoes of the opposite sex of ages ranging from 1–7 days. Males and females were also kept together continuously from emergence. The effect of increasing male/female ratios on the insemination rate was investigated as well. The insemination rate of An. arabiensis in the laboratory (96%) was similar to that found in nature, whereas that of our strain of An. gambiae s.s. was consistently low (maximum 72%), particularly after females had been together with males for a 24 h period only. The optimum age for insemination was 7 days for males and females of both species. The insemination rate of our strain of An. arabiensis was significantly higher at all ages than that of our strain of An. gambiae s.s. The latter strain became inseminated at the earliest when 4 days old. An increase in the male/female ratio significantly enhanced the insemination rate in both strains. It was found that motility of spermatozoa inside the spermatheca, once in contact with saline, could be used as a marker for the approximate time of insemination. It is concluded that the relatively low insemination rate of the Galisua strain of An. gambiae s.s. is unlikely to be caused by the rearing conditions. Other factors that may be responsible are discussed.
Effets d'un régulateur de croissance d'insectes, le fénoxycarbe, sur la diapause du psylle du poirier Cacopsylla pyri
Authors: Lyoussoufi A. , Gadenne C. , Rieux R. , d'Arcier F. Faivre 
Published: April 2011

AbstractEffects of an insect growth regulator, fenoxycarb, on the diapause of the pear psylla, Cacopsylla pyri Under natural conditions, winter‐form females undergo a reproductive diapause. Topical application on adults and treatment of young pear foliage with fenoxycarb show that this mimic of juvenile hormone (JH) accelerates ovarian maturation of winter‐form females, leading to a rapid breakdown of diapause. Treatment of males increases the mating rate of non‐treated females. The physiologically mature winter‐form males exhibit a behavioural arrest which can be eliminated by this insect growth regulator. Mating thus depends more on the ‘maturity of sexual behaviour’ of males than on the physiological maturity of females.RésuméLes femelles de forme hivernale de Cacopsylla pyri (L.) présentent dans les conditions naturelles une diapause reproductrice. L'application topique sur les adultes et foliaire sur jeunes poiriers du fénoxycarbe, montrent que ce mimétique de l'hormone juvénile (JH), accélère la maturation ovarienne et permet une levée rapide de la diapause. Le traitement des mâles augmente le taux de fécondation chez les femelles non traitées. Les mâles, très tôt physiologiquement mûrs, présentent un blocage comportemental qui est levé par ce régulateur de croissance. L'accouplement dépendrait ainsi plus de ‘la maturité du comportement sexuel’ des mâles que de la maturité physiologique des femelles.
Aggregation patterns of Bemisia tabaci in response to insecticide applications
Authors: Athayde Tonhasca Jr.  , Palumbo John C. , Byrne David N. 
Published: April 2011

AbstractWe measured the effect of insecticide applications on the distribution patterns of the sweet potato whitefly, Bemisia tabaci (Gennadius), in fields of cantaloupe, Cucumis melo L., in Yuma, Arizona. Whitefly infestations were measured by counts of adults, eggs, first to mid/fourth instars, and late‐fourth instars (‘red‐eyed’) nymphs. Adults were sampled from the entire leaf, and immature stages were counted in a 1‐cm2 area of a leaf. The indices b (Power Law), β (Patchiness regression) and Id (Morisita) indicated that all life stages were aggregated, but results for the three indices were not similar for determining the relative aggregation levels between treatments. In general, indices β and Id indicated higher aggregation in insecticide‐treated fields, whereas b had mixed results. The Morisita index was sensitive to a few unusually high means among a series of low densities in the treatment plots, what could be attributed to refuges due to failure in the insecticide applications. Despite the usefulness of the Power Law and the Patchiness regression for describing the relationship between spatial or temporal variability and mean densities, we suggest that Id is more appropriate for expression of spatial distribution because it is based on a precise definition of aggregation.
An antimony‐silver/silver chloride electrode system for measuring pH in insect gut contents
Authors: Biggs David R. , Greenway Robert M. , McGregor Peter G. 
Published: April 2011

AbstractAn electrode system consisting of a cast antimony rod with a silver chloride‐coated wire as a reference electrode has been developed to measure pH in insect gut contents. The electrode works well with buffer volumes down to 0.1 μl. Response to pH is linear between pH 4 and 11 and equates to a change of 52.3 mV per pH unit at 18–20 °C. Electrical resistance is low (0.25 MΩ), so the electrode can be used with low‐impedance meters and does not require shielding from induced currents. Its useful range lies between redox potentials −330 mV (pH 7) and +297 mV to 350 mV, corresponding to a pe + pH range of 1.4 to about 10.8. This covers reported gut pH values for most insects so far examined. Consequently the electrode is suitable for measuring pH of gut contents from many insects that are too small to be analysed with current commercial electrodes.
Disrupting spring colonization of Colorado potato beetle to nonrotated potato fields
Authors: Weber D. C. , Ferro D. N. , Buonaccorsi J. , Hazzard R. V. 
Published: April 2011

AbstractOverwintering Colorado potato beetles (Leptinotarsa decemlineata (Say)) were concentrated primarily within woody borders, and mortality was lower in borders than in potato fields. After overwintering, only 15–44% of live beetles were in the potato fields. In experiments with small plots, colonization of fields from woody borders was reduced ∼ 60% by a trap crop, either treated with adulticide or with beetles collected daily. Such trap crops, or simply pitfall traps to prevent colonization from woody borders, could significantly reduce early‐season adult numbers and subsequent larval populations. However, success is dependent on the local densities of overwintered beetles, and the prevalence of arrestment behavior in the case of trap crops.
Stabilité du polymorphisme enzymatique dans les populations d'un Lépidoptère migrant, Agrotis ipsilon
Authors: Buès R. , Freuler J. , Toubon J. F. , Gerber Susanna , Poitout S. 
Published: April 2011

SummaryHomogeneous population structure in a migrant Lepidoptera, Agrotis ipsilon.Light trapping of Agrotis ipsilon (Lepidoptera, Noctuidae) on various passes of the Alps and Pyrénées exhibited wide range movements between overwintering and aestivation areas. Electrophoretic analysis of samples taken in the Cantons of Vaud and Tessin (Switzerland), in the Rhône Delta (Southern France), and on passes of the Alps and Pyrénées, showed a great temporal and spatial homogeneity of allele frequencies (Fst values ranging from 0.002 to 0.013, and genetic distances from 0 to 0.004). These results support the hypothesis of a high level of gene flow. However, the occurrence during some years of high Fis values, might be explained by mixtures of populations that had undergone selection or went through a bottle‐neck.