bluuebunny/crossref_metadata_2025_split huggingface dataset:
Indiscrimination of Manduca sexta larvae to overexpressed and underexpressed levels of phenylalanine ammonia‐lyase in tobacco leaves
Authors: Eichenseer H. , Bi J.L. , Felton G.W. 
Published: October 2003

Abstract Manduca sexta (L.) larvae were unable to discriminate between transgenic tobacco leaves expressing high or low levels of phenylalanine ammonia‐lyase (PAL) in dual choice arenas. Tobacco leaves overexpressing PAL had up to ten times more chlorogenic acid and up to twice as much rutin in their leaves than leaves containing the same sense‐suppressed gene. Caterpillars reared previously on artificial diet or tobacco leaves had no preference for either leaves over‐ or underexpressing PAL. Application of exogenous chlorogenic acid to PAL‐suppressed leaves at levels similar to the overexpressed leaves did not affect M. sexta's choice. When applied at higher rates, treated leaves were preferred by caterpillars reared on tobacco leaves but not by diet‐reared larvae. Our results with leaves confirm earlier studies with M. sexta using simpler substrates and mixtures of test compounds and provides further evidence that leaf phenolics, such as chlorogenic acid, do not act as feeding deterrents for larval M. sexta.
Oviposition and offspring survival within eggs of European corn borer: discrimination of the host embryo by female Trichogramma nubilale
Authors: Olson D.M. 
Published: October 2003

AbstractOviposition preference and offspring survival relative to the location of the host embryo was tested in the egg parasitoid Trichogramma nubilale on European corn borer host eggs. Females preferentially oviposited near to the embryo on hosts about 24 h old. Survival of Trichogramma was lower when females oviposited far from the embryo, and a higher proportion of host embryos hatched. Females did not show preferences for drilling or oviposition within very young hosts relative to where the embryo would develop, and these eggs did not produce wasps or host larvae. Female behavior was apparently adaptive in day‐old hosts, not to very young hosts.
Effects of targets impregnated with the chitin synthesis inhibitor triflumuron on the blowfly Lucilia sericata
Authors: Smith K. E. , Wall R. 
Published: October 2003

AbstractThe effects of exposure of adults of the blowfly Lucilia sericata (Meigen) for 24 h to cloth targets impregnated with the chitin synthesis inhibitor triflumuron plus sucrose or sucrose only, were considered. When both male and female L. sericata were exposed to targets treated with sucrose only, the percentage egg hatch varied between 60–75%. When both sexes were exposed to targets treated with 10% triflumuron plus sucrose the percentage egg hatch varied between 3–7%. When females alone were exposed to triflumuron, prior to the introduction of unexposed males, egg hatch varied between 4–14%. The exposure of males alone to 10% triflumuron treated targets, prior to the introduction of unexposed virgin females, did not give any consistent significant decrease in the mean percentage egg hatch. However, repetition of this trial with males exposed to targets treated with 15 or 20% triflumuron, resulted in a percentage egg hatch of 3.1% and 10.3%, respectively. These results suggest that at relatively high target concentrations, males can transfer effective doses of triflumuron to unexposed virgin females.The exposure of adults to triflumuron treated targets did not significantly increase the mortality of either male or female L. sericata. Furthermore, bioassays showed that there was no significant decline in the ovicidal effectiveness of targets treated with 10% triflumuron and sucrose solution following exposure to sun and rain for up to 8 weeks in 1995 and 1996.The results suggest that targets treated with triflumuron suspension concentrate and sucrose may form the basis of an effective system for the control of L. sericata in the field. However, the relatively high concentrations of triflumuron required and the low efficiency with which males are able to transfer effective doses to unexposed females may diminish one of the main theoretical advantages of using a chitin synthesis inhibitor, such as triflumuron, over a conventional insecticide.
Effect of a co‐occurring aphid on the susceptibility of the Russian wheat aphid to lacewing predators
Authors: Bergeson Erin , Messina Frank J. 
Published: October 2003

AbstractPrevious field experiments indicated that the presence of the bird cherry‐oat aphid, Rhopalosiphum padi (L.), on perennial grasses can decrease the effectiveness of predatory lacewings, Chrysoperla plorabunda (Fitch), in reducing populations of the Russian wheat aphid, Diuraphis noxia (Mordvilko). We tested the hypothesis that R. padi deflects predation away from D. noxia because it feeds in sites that are more accessible to predators. We quantified the behavior of lacewing larvae on crested wheatgrass plants bearing either D. noxia alone or an equal mixture of D. noxia and R. padi. On non‐flowering plants, R. padi typically occurred on leaf sheaths or open blades, and was encountered and captured more often than D. noxia, which usually fed within immature, rolled leaves. Overall time‐budgets of lacewings did not differ between the pure‐D. noxia and mixed‐species treatments, but >75% of the time spent consuming aphids in the mixed‐species treatment was devoted to R. padi. On flowering plants, D. noxia usually aggregated on the flag leaf below the inflorescence, whereas R. padi occurred mostly on leaf sheaths. Predators again captured R. padi more often than D. noxia, and spent more time consuming aphids in the mixed‐species treatment than in the pure‐D. noxia treatment. These behavioral observations support the hypothesis that non‐target prey can hamper the short‐term effectiveness of biological‐control agents against D. noxia.
Expression of early and late‐emerging phenotypes in both diapausing and non‐diapausing Delia radicum L. pupae
Authors: Biron D. , Langlet X. , Boivin G. , Brunel E. 
Published: October 2003

AbstractThe presence of early and late phenotypes of Delia radicum L. (Diptera: Anthomyiidae) has been attributed to the existence of differences in development after diapause. The criteria for the early phenotype is emergence in less than 20 days at 20 °C (320 DD above 4 °C) and more than 30 days at 20 °C (280 DD above 7 °C + 320 DD above 4 °C) for the late phenotype. The emergence pattern of 10008 non‐diapausing D. radicum pupae reared at 20 °C, L16:D8 and 60% r.h. showed an asymmetrical bimodal distribution similar to the emergence pattern of 477 (1994) and 326 (1995) diapausing pupae from the field. When reared individuals were segregated based on their emergence pattern and reared separately, the proportion of early phenotype increased from 61 to 96% in three generations, while the proportion of late phenotype stayed at 78 to 80% during three generations. These results indicate clearly that diapause is not necessary for the expression of the early and late phenotypes. The presence of these two phenotypes probably enables D. radicum to optimize the use of the available resources, to ensure that a sizeable proportion of the larval population enters diapause and to maintain its distribution throughout the holarctic region (35 to 68 °N).
Survival, fecundity and fertility of Bactrocera oleae, as affected by amino acid analogues
Authors: Zografou E. N. , Tsiropoulos G. J. , Margaritis L. H. 
Published: October 2003

AbstractThe effect of twenty five amino acid analogues at various concentrations upon the adult olive fruit fly Bactrocera oleae Gmelin (Diptera: Tephritidae), was tested. Insect survival was significantly shortened by the following amino acid analogues: (in parentheses are indicated the antagonized amino acids) D‐cycloserine (alanine), L‐glutamic acid‐γ‐hydrazide (glutamine), DL‐allyl‐glycine (cysteine), L‐canavanine (arginine), L‐methionine‐DL‐sulfoximine (methionine) and 3,4‐dehydro‐DL‐proline (proline). Fecundity was significantly reduced by the same analogues plus aminoethanesulfonic acid (glycine), taurine (alanine), L‐norvaline (leucine), a‐methyl‐DL‐serine (serine), DL‐hydroxyglutamic acid (glutamic acid), (S)‐2‐(aminoethyl)‐L‐cysteine (lysine), a‐methyl‐DL‐methionine (methionine) and a‐methyl‐DL‐histidine (histidine). All the above amino acid analogues also depressed egg‐hatching with the exception of taurine, DL‐hydroxyglutamic acid, DL‐allyl glycine, a‐methyl‐DL‐methionine and a‐methyl‐DL‐histidine. Finally, y‐glutamyl‐p‐nitroanilide (glutamic acid), crotyl‐glycine (methionine), DL‐7‐azatryptophan and 5‐methyl‐DL‐tryptophan (tryptophan), DL‐1,2,4 triazole‐3‐alanine (histidine) and DL‐pipecolic acid (proline) did not affect any of the parameters tested.
Chemoreception of oviposition inhibiting terpenoids in the diamondback moth Plutella xylostella
Authors: Qiu Yu‐Tong , van Loon Joop J.A. , Roessingh Peter 
Published: October 2003

AbstractThe effects of six terpenoids and two terpenoid containing extracts of the neem tree (Azadirachta indica A. Juss.) on oviposition by the diamondback moth (Plutella xylostella L., Yponomeutidae: Lepidoptera) were tested. Two drimane terpenoids, the sesquiterpenoid polygodial and the neem extract Margosan‐O exerted significant inhibitory effects at the dosages tested. Ablation experiments showed that both antennae and fore‐tarsi contributed to mediation of the inhibition by a drimane. Location of chemosensilla on prothoracic tarsi and ovipositor was examined by scanning electronmicroscopy. Electrophysiological recordings from ovipositor and tarsal taste sensilla showed that distilled water produced distinct responses from one neuron. In tarsal sensilla, ethanol and drimane solutions produced responses from two neurons, one of which might be the water cell that fired at a reduced rate. A drimane significantly decreased the responses of tarsal chemoreceptors to a cabbage leaf extract, which is a possible sensory mechanism leading to behavioural avoidance of this compound.
Habitat diversification tactic for improving biological control: parasitism of the western grape leafhopper
Authors: Murphy Brook C. , Rosenheim Jay A. , Dowell Robert V. , Granett Jeffrey 
Published: October 2003

AbstractIn a previous study we demonstrated greater abundance of the parasitoid Anagrus epos (Girault) in grape vineyards located downwind of prune trees that function as overwintering habitats. This study examines whether these higher A. epos numbers translated into higher egg parasitism rates of the grape leafhopper, Erythroneura elegantula (Osborn). Paired commercial wine‐grape vineyard plots, one with and one without adjacent prune trees, were studied within a complete block design in northern and central California. A. epos was the key mortality factor affecting E. elegantula eggs. Point estimates of A. epos parasitism rates were significantly greater in vineyards associated with prune trees during the first E. elegantula generation in both 1991 and 1992. No consistent differences in parasitism rates were observed during the second or third generations. The results indicated that prune trees enhance early season parasitism rates. Cumulative estimates of egg parasitism across E. elegantula generations demonstrated that enhanced early‐season parasitism resulted in a net season‐long increase in the degree of mortality imposed by A. epos on E. elegantula eggs. Two factors were found to influence parasitism rates: the abundance of early‐season A. epos adults moving into vineyards and the density of E. elegantula eggs in vineyards. Our results indicate that diversification of vineyards using prune trees supports overwintering populations of a specialist parasitoid and thereby alters host‐parasitoid interactions to favor enhanced parasitism in vineyards.
Are differences in life history parameters of the pine beauty moth Panolis flammea modified by host plant quality or gender?
Authors: Leather S. R. , Beare J. A. , Cooke R. C. A. , Fellowes M. D. E. 
Published: October 2003

AbstractPine beauty moth (Panolis flammea D&S, Lepidoptera: Noctuidae) were reared individually from egg hatch to pupation on one of three host plants, Pinus sylvestris (native host plant), Pinus contorta (Central Interior seed origin – good quality introduced host) and P. contorta (Alaskan seed origin – poor quality introduced host). After emerging from the pupae the adult moths were confined to a Skeena River seed origin of P. contorta. Female pupal weight and adult life span were significantly higher on P. sylvestris than on the two lodgepole pine seed origins. Development time was, however, not significantly different between treatments, but larval mean relative growth rate was found to be negatively correlated with birth weight and positively correlated with pupal weight. The time to emerge from the pupa was also not significantly different between treatments. However, there were marked differences between the genders. Male moths lost a significantly greater proportion of their weight over the pupal stage but lived significantly longer as adults than the females. Female moths emerged from the pupal stage significantly sooner than male moths. There was no apparent advantage of large birth size when looked at in terms of subsequent performance. These results are discussed in light of current life history theory.
Endocrine background of how 20‐hydroxyecdysone agonist, RH 5849, influences diurnal pattern of pupation in Spodoptera littoralis
Authors: Pszczolkowski Maciej A. , Kuszczak Barbara , Smagghe Guy 
Published: October 2003

AbstractUnder laboratory conditions (L16:D8, 24°C, r.h. 80%), applying of an ecdysone agonist, RH 5849, (1,2‐dibenzoyl‐1‐tert‐butylhydrazine) onto final instar larvae of Spodoptera littoralis (Boisd.), Noctuidae, Lepidoptera, delayed or advanced the time of pupation depending on the time of treatment. This response was dose‐dependent. In addition, non‐lethal doses of RH 5849, ranging from 0.05 to 10 μg/larva were used. Following treatment of S. littoralis larvae with 5 μg RH 5849 the endogenous ecdysteroid level was increased or decreased depending on the time of application. Based on the results presented, we suggest that potential users of non‐steroidal ecdysone agonists should consider the proper circadian timing of application in the field.
High temperature induced diapause in the cotton bollworm Helicoverpa armigera
Authors: Nibouche Samuel 
Published: October 2003

AbstractIn laboratory studies, Helicoverpa armigera (Hübner) (Lep. Noctuidae) from Burkina Faso exhibited pupal dormancy induced by high temperatures. Exposure to 37 °C from the 3rd larval stage caused 94.7% of males to diapause but only 60.9% of females. No influence of daylength (12 and 16 h) was observed. Induction by high temperatures must begin during the larval stage to be effective. The pupal stage is not sensitive to induction. After storage at 37 °C for 60 days, 64.3% of dormant pupae survived and most of them resulted in adult emergence. After storage at 37 °C for 85 days, no dormant pupae survived. The development of dormant pupae is resumed after about 20 days at 21 °C whatever the duration of prior exposure to 37 °C (7, 14 or 30 days). There is no delay in non‐dormant pupae kept at 21 °C. The possible role of this ‘hot thermal diapause’ in the life history of H. armigera in Burkina Faso is discussed.
Trees or stores? The origin of migrating Prostephanus truncatus collected in different ecological habitats in southern Benin
Authors: Borgemeister C. , Tchabi A. , Scholz D. 
Published: October 2003

AbstractMigrating Prostephanus truncatus (Horn) (Col.: Bostrichidae) were collected weekly with pheromone‐baited funnel traps at three different sites in southern Benin for 12 months. One site was located in a primary forest, one in a peri‐urban area, and one in a region with intensive agriculture. The sex of the trapped beetles was determined. The gut‐content of the specimens was analyzed for remains of lignin and starch, the former indicating recent feeding on woody, the latter on a starchy substrate, such as stored maize or dried cassava. At all locations, the sex ratio of migrating P. truncatus was significantly female‐biased, with the greatest proportion of females trapped at the peri‐urban site. At the forest site, most beetles had lignin in their guts, while the proportion of beetles containing starch was highest in the peri‐urban site. Approximately equal proportions of beetles with either starch and lignin were trapped in the region with intensive agriculture. The results are discussed with regard to the population dynamics of P. truncatus in different habitats and the flight activity of the beetles.
Selection of biting sites on a human host by Anopheles gambiae s.s., An. arabiensis and An. quadriannulatus
Authors: Dekker Teun , Takken Willem , Knols Bart G. J. , Bouman Edwin , van de Laak Stephan , de Bever Arjan , Huisman Piet W. T. 
Published: October 2003

AbstractThe selection of biting sites on a human host of three closely related mosquito species belonging to the African Anopheles gambiae complex (Diptera: Culicidae), Anopheles gambiae Giles s.s., An. arabiensis Patton and An. quadriannulatus Theobald, was investigated under controlled laboratory conditions. Although these species differ in host preference, they all showed a significant preference to bite the legs and feet, suggesting that a mutual not specifically human factor was involved in the selection of biting sites. In subsequent experiments with An. gambiae s.s. this factor was revealed by altering the position of the test person. In experiments with the test person sitting on a stool, the legs and feet were significantly preferred as biting sites, whereas lying on the ground, with the legs and feet sticking up, the latter body parts were bitten significantly less than the body parts closest to the ground (head, trunk and arms). The results indicate that mainly convection currents along the host are used by members of the An. gambiae complex in selecting a biting site. In contrast to An. gambiae s.s. and An. arabiensis, large numbers of bites by An. quadriannulatus also occurred on the head, possibly in response to exhaled breath. It is concluded that the selection of biting sites of members of the Anopheles gambiae complex is guided by convection currents and partially mediated by host odours.
Geographical variation in insect developmental period: effect of host plant phenology on the life cycle of the bruchid seed feeder Kytorhinus sharpianus
Authors: Ishihara Michihiro 
Published: October 2003

AbstractThe voltinism of the bruchid Kytorhinus sharpianus Bridwell (Coleoptera: Bruchidae) and the phenology of its host plant Sophora flavescens Aiton (Leguminosae) were observed at four latitudes: Aomori (40°46′ N), Obanazawa (38°37′ N), Kujiranami (37°21′ N) and Mitsuma (36°05′ N) in northeastern Honshu (Japan). Kytorhinus sharpianus life cycle ranged from bivoltine and partially trivoltine in the south to univoltine and partially bivoltine in the north. Sophora flavescens started growing later in spring at higher latitudes. However, the relative growth rate was higher in the north (Aomori) than in the south (Mitsuma). In parallel with this, the first‐generation of adult K. sharpianus appeared later at higher latitudes. When the four local populations were reared at 24 °C, L16:D8 and 65% r.h., males developed faster than females. The mean developmental time showed a saw‐toothed latitudinal cline. The reversion in the latitudinal trend of variation corresponded to the change in the major type of life cycles from univoltine to bivoltine. Two heat units throughout the year and post‐fruiting period were calculated as the sums of degree‐days above the developmental threshold (12 °C) of K. sharpianus. Both heat units decreased in parallel with each other with increasing latitude. The greater growth rate of hosts in the northern population compensated for the smaller heat units. In addition, when the heat units were divided by the degree‐days needed to complete development, the numerical value was the approximate number of generations observed in each locality.
Olfactory and gustatory behaviour by larvae of Lobesia botrana in response to Botrytis cinerea
Authors: Mondy N. , Pracros P. , Fermaud M. , Corio‐Costet M.‐F. 
Published: October 2003

AbstractIn vineyards, larvae of Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) and Botrytis cinerea (Persoon: Fries) often occur together. This study was carried out to establish whether first instar larvae are attracted by the fungus. Olfactory and gustatory responses of larvae to the fungus were investigated on grape berry clusters (Vitis vinifera) and in two types of olfactometer. In clusters infected partly by B. cinerea, 82% of first instar larvae settled where berries had been infected. In the olfactometers, first instar larvae detected and discriminated between two tested foods. They significantly preferred synthetic media or grape berries (cv., ‘Alphonse Lavallée’ or ‘Cabernet Sauvignon‘) infected with B. cinerea to non‐infected controls. The olfactory response led to 62.2% to 72.6% of the first instar larvae attracted by the fungus and the association of olfactory with gustatory responses resulted in similar rates (64.1% to 81.6%). So, the larvae were most attracted by synthetic media or grape berries infected by the fungus as compared to the controls. Olfaction appears to be the main sense involved in this attraction process.
Distinct feeding behavior between sexes of Frankliniella occidentalis results in higher scar production and lower tospovirus transmission by females
Authors: van, de Wetering F. , Hulshof J. , Posthuma K. , Harrewijn P. , Goldbach R. , Peters D. 
Published: October 2003

AbstractFeeding behavior and scar production of male and female F. occidentalis (Pergande) (Thysanoptera: Thripidae) were studied in relation to transmission of tomato spotted wilt tospovirus (TSWV). Electrical penetration graph (EPG) analysis showed that females feed more frequently and intensively than males. The feeding intensity, reflected by silvery scar production and studied by an image analysis system, demonstrated that females induced more numerous scars than males. At the same time, males transmitted TSWV with a higher efficiency than females, indicating that TSWV transmission and scar production are not positively correlated. Furthermore, males produced significantly more local lesions of TSWV than females. These quantitative differences in scar production and transmission of TSWV can be explained by the lower mobility and higher consumption rate of females. The influence of the sex‐ratio on crop damage and virus transmission, and thus to the spread of TSWV, is emphasized.