bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and evaluation of an enzyme‐linked immunosorbent assay to detect Pieris rapae remains in guts of arthropod predators
Authors: Schmaedick M.A. , Ling K.S. , Gonsalves D. , Shelton A.M. 
Published: October 2003

AbstractAn enzyme‐linked immunosorbent assay (ELISA) was developed to detect remains of Pieris rapae L. (Lepidoptera: Pieridae) immature stages in the guts of field collected arthropod predators. The assay can be used to help ascertain the relative importance of arthropod predator species in suppressing P. rapae in cabbage, Brassica oleracea var. capitata L. The ELISA is sensitive to all immature stages of P. rapae, although first and fifth instars can be detected more readily than eggs or pupae and third instars showed intermediate detectability. Assays on whole body homogenates of predators readily detected predation on P. rapae first instars by all seven of the predator species tested, although response generally declined with increasing predator size. Together the results show that the P. rapae ELISA possesses a sufficiently high level of sensitivity and specificity to be a useful tool in helping to elucidate the roles of arthropod predator species in reducing populations of P. rapae in cabbage.
Cry1Ab protein levels in phytophagous insects feeding on transgenic corn: implications for secondary exposure risk assessment
Authors: Head Graham , Brown Christopher R. , Groth Mark E. , Duan Jian J. 
Published: October 2003

AbstractEnzyme‐linked immunosorbent assays (ELISA) and bioassays were used to estimate levels of Cry1Ab protein in four species of phytophagous insects after feeding on transgenic Bt‐corn plants expressing Cry1Ab protein or artificial diets containing Cry1Ab protein. The level of Cry1Ab in insects feeding on sources containing the Cry1Ab protein was uniformly low but varied with insect species as well as food source. For the corn leaf aphid, Rhopalosiphum maidis (Fitch), feeding on diet solutions containing Cry1Ab protein, the level of the protein in the aphid was 250–500 times less than the original levels in the diet, whereas no Cry1Ab was detected by ELISA in aphids feeding on transgenic Bt‐Corn plants. For the lepidopteran insects, Ostrinia nubilalis (Hübner), Helicoverpa zea (Boddie), and Agrotis ipsilon (Hufnagel), levels of Cry1Ab in larvae varied significantly with feeding treatment. When feeding for 24 h on artificial diets containing 20 and 100 ppm of Cry1Ab, the level of Cry1Ab in the larvae was about 57 and 142 times lower, respectively, than the original protein level in the diet for O. nubilalis, 20 and 34 times lower for H. zea, and 10 to 14 times lower for A. ipsilon. Diet incorporation bioassays with a susceptible insect (first instar O. nubilalis) showed significant Cry1Ab bioactivity present within whole body tissues of R. maidis and O. nubilalis that had fed on diet containing a minimum of 20 ppm or higher concentrations (100 or 200 ppm) of Cry1Ab, but no significant bioactivity within the tissues of these insects after feeding on transgenic Bt‐corn plants. The relevance of these findings to secondary exposure risk assessment for transgenic Bt crops is discussed.
Chlorogenic acid as an antiherbivore defence of willows against leaf beetles
Authors: Ikonen Arsi , Tahvanainen Jorma , Roininen Heikki 
Published: October 2003

AbstractIn the leaves of 13 Finnish willow species, the content of a phenolic, chlorogenic acid, was found to vary from 0 up to 18 mg g−1 D.W. Effects of pure chlorogenic acid on insect feeding behaviour were tested using four common leaf beetle species which are in the field mainly found on willows with low‐chlorogenic acid leaves. One species, Lochmaea capreae L., was invariably deterred by pure chlorogenic acid applied in naturally occurring concentrations on the willow leaves. Accordingly, in 2‐choice laboratory feeding trials L. capreae was found to prefer low‐chlorogenic acid leaves of four willow species over high‐chlorogenic acid leaves of Salix pentandra L. and S. myrsinifolia Salisb. When presented on the leaves of S. phylicifolia L, pure chlorogenic acid inhibited also the feeding by Phratora polaris Sp.‐Schn. Instead, chlorogenic acid had no significant effect on Ph. polaris when it was presented on the leaves of another willow S. cinerea L. In laboratory, Ph. polaris did not show general preference for willow species with low chlorogenic acid content in their leaves. Thus, the response of Ph. polaris to chlorogenic acid seems to depend on the plant species. Apparently variation in other traits such as leaf hairyness may easily override the potential effect of chlorogenic acid content on Ph. polaris. To two other leaf beetle species, Galerucella lineola F. and Plagiodera versicolora Laich., chlorogenic acid is an ineffective deterrent even at unnaturally high concentrations. In laboratory, G. lineola and P. versicolora did not prefer willows with low chlorogenic acid content in their leaves. Thus, among four studied leaf beetle species, only L. capreae seems to be clearly affected by this phenolic. Therefore, overall importance of chlorogenic acid as a defence against willow‐feeding leaf beetles appears to be very limited.
Effects of elevated CO2 on five plant‐aphid interactions
Authors: Hughes Lesley , Bazzaz Fakhri A. 
Published: October 2003

AbstractWe investigated interactions between five species of phloem‐feeding aphids (Homoptera: Aphididae) and their host plants at elevated CO2; Acyrthosiphon pisum (Harris) on Vicia faba L., Aphis nerii Boyer de Fonscolombe on Asclepias syriaca L., Aphis oenotherae Oestlund on Oenothera biennis L., Aulacorthum solani (Kaltenbach) on Nicotiana sylvestris Speg. & Comes and Myzus persicae (Sulzer) on Solanum dulcamara L. Host plants grown at elevated CO2 generally had greater biomass, leaf area and C:N ratios than those grown at ambient CO2, while plants with aphids had lower biomass and leaf area than those without aphids.The responses of aphid populations to elevated CO2 were species‐specific with one species increasing (M. persicae), one decreasing (A. pisum), and the other three being unaffected. CO2 treatment did not affect the proportion of alate individuals produced. In general, aphid abundance was not significantly related to foliar nitrogen concentration.We performed separate analyses to test whether either aphid presence or aphid abundance modified the response of host plants to elevated CO2. In terms of aphid presence, only three of the potential 15 interactions (five aphid species x three plant traits) were significant; A. solani slightly modified the response of the plant biomass to elevated CO2 and M. persicae affected the response of leaf area and allocation. In terms of aphid abundance, only two of the potential 15 interactions were significant with A. nerii modifying the plant response to CO2 in terms of total leaf area and allocation.We conclude that, in contrast to other insect groups such as leaf chewers, populations of most phloem‐feeders may not be negatively affected by increased CO2 concentrations in the future. The reasons for this difference include the possibility that aphids may be able to compensate for changes in host plant quality by altering feeding behaviour or by synthesizing amino acids. In addition, there is little evidence that aphid herbivory, even at high levels, will substantially modify the response of plants to elevated CO2.
Egg‐laying, pre‐imaginal growth dynamics, and mortality in Eupelmus orientalis and Dinarmus basalis, two solitary ectoparasitoids of Callosobruchus maculatus
Authors: Damiens David , Imbert Eric , Bressac Christophe , Thibeaudeau Christian , Chevrier Claude 
Published: October 2003

AbstractIn Eupelmus orientalis and Dinarmus basalis, two ectoparasitoid species of Callosobruchus maculatus larvae, pre‐imaginal development occurs within a leguminous seed, and is then impossible to observe directly. Offspring sex ratio is normally determined when adults emerge, and mortality during pre‐imaginal stages remains unknown. By using translucent gelatine capsules containing a host larva to mimic the seed, we conducted an experimental study of offspring production and sex ratio with measurements of growth and pre‐imaginal mortality. Mated females were allowed to lay eggs on hosts in seeds or in gelatine capsules. In the gelatine capsules the parasitoid was observed daily and measured to assess if the offspring sex ratio can be determined before emergence of adults. When seeds are replaced with gelatine caps, the number of egg‐laying females decreases (48% in Eupelmus orientalis and 72% in Dinarmus basalis of females ovipositing on seeds lay eggs on gelatine capsules), and the offspring output changes qualitatively in Eupelmus orientalis (egg numbers constant, sex ratio diminishing from 0.75 to 0.46) and quantitatively in Dinarmus basalis (egg numbers diminishing, sex ratio maintained about 0.7). In Eupelmus orientalis, pre‐imaginal mortality occurs principally in the first three days, the critical stage is hatching, and the final mortality is 30.1%. In Dinarmus basalis, mortality of larvae increases gradually from the 2nd to the 7th day, the final mortality being 13.6%. (3) In both species sex of the offspring can be determined before emergence but only after most mortality has occurred.
Evidence of an extractable semiochemical produced by Rhopalosiphum padi acting on Psammotettix alienus
Authors: Alla S. , Moreau J.P. , Frérot B. 
Published: October 2003

AbstractIt has previously been shown that the aphid Rhopalosiphum padi (L.) (Homoptera: Aphididae) adversely affects the biology of the leafhopper Psammotettix alienus (Dahlbom) (Homoptera: Cicadellidae) (Alla et al., 2001). In this work, we demonstrate that this effect was due to chemical components produced by the aphid.The increase in the number of aphids in the presence of the leafhopper on wheat caused nymphal mortality, an extended duration of the development and a decrease in nymph production of the leafhopper. Extract of aphids in methanol‐water (50/50: v/v), applied on plants significantly increased the mortality in the leafhopper nymphs at both 3AE (3 Aphid Equivalent) and 7AE doses. At the same doses, both the honeydew and water extract of aphids did not have any effect. At the 20AE dose, aphid extracts in methanol‐water led to a longer development time and strong mortality in leafhopper nymphs. In female adults of the leafhopper, neither the aphid extracts in methanol‐water nor the honeydew showed a conclusive result, but generally, daily nymph production decreased with the increase in the extract doses.These results confirmed the depressive effect of R. padi on P. alienus and showed that this interaction was chemical. The active component(s) is partially extracted in a blend of methanol‐water (50/50: v/v). Further studies to identify this component(s) will be undertaken.
Comparison of gregariousness in larvae and adults of four species of zetoborine cockroaches
Authors: van Baaren Joan , Deleporte Pierre 
Published: October 2003

AbstractInsects observed in groups in nature may be gathered either by attractants from the environment or by conspecifics. Field distribution data alone are thus insufficient to assess congregation by conspecifics and complementary laboratory tests of spacing patterns are required. Such tests were performed in four species of Zetoborinae (Insecta, Blattaria), for which field studies showed differences in spatial distribution (Schultesia lampyridiformis Roth, Phortioeca nimbata Burmeister, Lanxoblatta emarginata Burmeister and Thanatophyllum akinetum Grandcolas). Gregariousness, mobility, and sticking to shelters were compared between these four species. Tests were performed on pairs of adults of the same sex and opposite sexes, and also on first instar larvae, either in isolation or in groups of two and four individuals. In S. lampyridiformis, adults were strongly gregarious, whereas larvae dispersed early after birth and were very mobile during the first instar. In P. nimbata, larvae and adults were gregarious, while in L. emarginata larvae were weakly gregarious, and gregariousness decreased when density increased. Adults of L. emarginata seemed to be indifferent to each other. Larvae and adults of T. akinetum were solitary and they actively dispersed. The varying levels of gregariousness among species are discussed according to the known ecological habits in Zetoborinae.
Protection of lodgepole pines from mass attack by mountain pine beetle, Dendroctonus ponderosae, with nonhost angiosperm volatiles and verbenone
Authors: Huber D.P.W. , Borden J.H. 
Published: October 2003

AbstractA number of angiosperm nonhost volatiles (NHVs) and green leaf volatiles (GLVs) were tested alone and as supplements to the antiaggregation pheromone, verbenone, for their ability to disrupt attack by the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae), on lodgepole pine, Pinus contorta Dougl. ex Loud. var. latifolia Engel. Preliminary experiments led to a refined NHV blend [benzyl alcohol, guaiacol, benzaldehyde, nonanal, salicylaldehyde, and conophthorin] and a refined GLV blend [(Z)‐3‐hexen‐1‐ol and (E)‐2‐hexen‐1‐ol]. In a 20‐replicate experiment, NHV and GLV groups both singly, and verbenone alone, significantly reduced MPB mass attack on pheromone‐baited trees and on trees within 5 m of the pheromone‐baited trees. Both blends in combination with verbenone reduced the number of mass attacked, baited trees to three out of 20 compared to 20 out of 20 of the baited controls. Each binary combination was also effective at reducing mass attack. In these experiments, all tested repellents were released from devices stapled to trees at the same point as the pheromone bait, suggesting that the repellency could have been to a point source, rather than to the whole tree. Therefore, in two further experiments bands of release devices were wrapped around the treated trees and the pheromone bait was removed from the treated trees. In one experiment, when the aggregation pheromone bait was suspended between pairs of trees treated with the NHV blend plus GLV blend plus verbenone, only three out of 25 treated pairs had mass attack on at least one member of the pair. In the other 60‐replicate experiment, with no pheromone baits present, attack occurred on 13 untreated and 11 banded trees, all in the path of a large advancing infestation. However, the mean attack density on the banded trees was significantly reduced to a level below the 40 attacks m−2 of bark surface required to kill a healthy lodgepole pine. As a result of these experiments, operational trials are recommended.
Genetic analysis of larval survival and larval growth of two populations of Leptinotarsa decemlineata on tomato
Authors: Lu Wenhua , Kennedy George G. , Gould Fred 
Published: October 2003

AbstractThe genetics of adaptation to tomato in Leptinotarsa decemlineata (Say) were investigated in reciprocal F1, F2, and backcross populations generated from crosses between beetles from a tomato adapted population and from a population that was poorly adapted to tomato. Larvae from the parent and test populations were reared on tomato for four days, after which survivorship and larval weights were recorded. Most results indicate that differences in larval growth and survival on tomato between the parent populations are largely determined by autosomal, polygenic mechanisms, the inheritance of which involves a significant dominance component. However, results from F2 crosses are not consistent with this conclusion. A significant difference in larval weights, but not in survival, between reciprocal F1 populations in an analysis of combined data from four separate experiments suggests that maternal cytoplasmic effects may contribute to differences in larval performance on tomato between the adapted and unadapted populations. The unusual results obtained from F2 crosses in this study are not atypical of results from previous studies of the genetics of adaptation to host plants by the Colorado potato beetle. Host plant adaptation by Colorado potato beetles may therefore involve unusual genetic mechanisms that are not easily assessed by classical Mendelian analysis.
Body colour and genetic variation in winged morph production in the pea aphid
Authors: Weisser Wolfgang W. , Braendle Christian 
Published: October 2003

AbstractAphids (Homoptera: Aphidoidea) produce a number of different phenotypes in their life‐cycle, among which are winged (alate) and wingless (apterous) morphs. Lowe & Taylor (1964) and Sutherland (1969a, b) were the first to suggest that aphid clones differ in their propensity to produce the winged morph and that in the pea aphid (Acyrthosiphon pisum Harris), this propensity is linked to the colour of the phenotype. We tested for the occurrence of genetic variation in winged morph production by rearing individuals from red and green clones of pea aphid under wing‐inducing (crowding) and control conditions, and scored the phenotypes of their offspring. Clones differed significantly in alate production and red clones produced on average a higher proportion of winged morphs than green clones. Importantly, however, there was considerable variation between clones of the same colour. Broad‐sense heritabilities of winged morph production were 0.69 (crowding treatment) and 0.63 (control). Clones also differed in the number of offspring they produced. When exposed to the crowding stimulus, aphids deferred offspring production, resulting in a higher number of offspring produced in the crowding treatment than in the control.
Receptor based models for spontaneous colour choices in flies and butterflies
Authors: Kelber Almut 
Published: October 2003

AbstractColour is one of several stimuli used by herbivorous insects in host choice. Insects have between 2 and 5 different types of photoreceptors to catch quanta of different wavelengths of the spectrum. Many insects have been shown to possess opponent neural interactions between the receptors that enable them to see colour. I present simple models to describe colour choices as functions of the receptor quantum catches and linear interactions of the receptor types. Models are applied to data sets obtained from own experiments and from the literature, on Pieris brassicae and P. rapae (Lepidoptera, Pieridae), Papilio aegeus (Papilionidae), Dacus oleae (Diptera, Tephritidae) and Eristalis tenax (Syrphidae). In fruit flies, detection of green fruit is based on an inhibitory interaction between a green‐sensitive receptor type and a blue‐sensitive receptor type. This might explain the preference many herbivorous insects have for yellow over green stimuli. Pollen feeding in hoverflies might have evolved from yellow pollen being a super‐normal stimulus for herbivorous insects. In butterflies, an additional red‐receptor is involved in the colour choice for an oviposition substratum and leads to them choosing green and not yellow. The models introduced in this study open new perspective for a physiological understanding of the design of visual stimuli for monitoring and trapping pest insects.
Effects of augmentative releases of the coccinellid, Adalia bipunctata, and of insecticide treatments in autumn on the spring population of aphids of the genus Dysaphis in apple orchards
Authors: Kehrli P. , Wyss E. 
Published: October 2003

AbstractThe impact of augmentative releases of indigenous predators and insecticide applications to control the autumn aphid forms of the genus Dysaphis (Homoptera: Aphididae), major pest insects on apple trees, was assessed in one‐year field experiments in Switzerland. Eggs and larvae of the two‐spot ladybird beetle Adalia bipunctata (L.) (Coleoptera: Coccinellidae) were released on 4‐year old apple trees in various numbers at five different dates in autumn 1998 when sexuales of the aphids were present. Additionally, Pyrethrum HP was sprayed at the same five dates to compare the effectiveness of these augmentative releases to a commonly applied insecticide. Augmentative releases of larvae before mid‐October significantly prevented the deposition of overwintering eggs by aphids of the genus Dysaphis and consequently reduced the number of hatched fundatrices in spring, 1999. There was a significant negative functional response among the number of released coccinellid larvae in autumn 1998 and the number of observed fundatrices on apple trees in spring 1999. Applications of Pyrethrum HP before mid‐October were more effective than augmentative releases of larvae of A. bipunctata. The release of coccinellid eggs had no impact on the number of fundatrices of the genus Dysaphis in the next spring because they did not hatch due to bad weather conditions. The weather conditions in autumn seemed to have an impact on the autumn migration of the winged aphids back to their primary host. The prevention of egg deposition of aphids in autumn is a promising control strategy and deserves further exploration for practical use.
Analysis by DC–EPG of the resistance to Bemisia tabaci on an Mi‐tomato line
Authors: Jiang Y.X. , Nombela G. , Muñiz M. 
Published: October 2003

AbstractThe tomato Mi gene confers resistance to nematodes, Meloidogyne spp., and to the potato aphid, Macrosiphum euphorbiae (Thomas). Previous greenhouse choice assays with Bemisia tabaci (Gennadius) showed that tomato commercial varieties carrying this gene had significantly lower values of host suitability and whitefly reproduction than varieties lacking Mi. This indicated that Mi, or another gene in its region, could regulate partial resistance. In order to characterise this resistance, probing and feeding behaviour of Bemisia tabaci B‐biotype was studied with DC Electrical Penetration Graph (EPG) technique on the near‐isogenic tomato lines Moneymaker (without Mi) and Motelle (carrying Mi). Significant differences (P < 0.05) between tomato lines were found in EPG parameters related to epidermis and/or mesophyll tissues. On Motelle, a lower percentage of whiteflies achieved phloem phase and they made more probes before attaining first phloem phase, had a higher ratio (number of probes before first phloem phase)/(total number of probes), had a longer total duration of non‐probing time, and a longer time before making the first intracellular puncture and before making the first phloem phase. In contrast, most of the parameters related to phloem phase were found not to differ significantly between these near‐isogenic lines. The behavioural data strongly suggest that the partial resistance in the variety Motelle is due to factors in the epidermis and/or mesophyll that inhibit the whiteflies from reaching phloem sieve elements. However, once the stylets reach a sieve element, whitefly behaviour did not differ between the two varieties. Thus, phloem sap of the two varieties appears to be equally acceptable to the whiteflies. Further studies are necessary to provide a better understanding of these mechanisms of resistance to whiteflies in tomatoes.