bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acceptability and suitability of seven plant species for the mealybug Phenacoccus parvus
Authors: Marohasy Jennifer 
Published: October 2003

AbstractSurvival, development and fecundity of cohorts of the mealybug Phenacoccus parvus Morrison were measured over one generation on seven plant species representing four plant families. Survival, development and fecundity were not significantly higher on the mealybug's principal field host, the weed Lantana camara L. (Verbenaceae), than on other plant species including Lycopersicon esculentum Miller (tomato) and Solanum melongena L. (eggplant). The acceptability of the leaves of the seven plant species to P. parvus first instar crawlers was measured on hatching, after active walking and after food deprivation. Lantana camara was the highest ranked plant species for all treatments. The number of crawlers settling on lower ranked plant species increased with the level of food deprivation.
Gypsy moth (Lymantria dispar) larval development and survival to pupation on diet plus extractables from green ash foliage
Authors: Markovic Ingrid , Norris Dale M. , Nordheim Erik V. 
Published: October 2003

AbstractGypsy moth, Lymantria dispar L., rate of larval development, molting, pupal weight and survival were studied on an artificial diet containing different concentrations of green ash ethyl acetate extractables (EtOAc Exts). Insects were reared on experimental diets from egg to pupa. Addition of EtOAc Exts to artificial diet significantly prolonged larval development and reduced their survival compared to larvae reared on control diet. Weights of pupae were significantly reduced when larvae were reared on diet containing the lowest dosage of EtOAc Exts (i.e., 0.01%) versus on control diet. EtOAc Exts in diet (e.g., 0.01, 0.06 and 0.2%) frequently caused incomplete ecdysis which invariably resulted in larval death. Impaired feeding, locomotion and excretion are likely causes of death. The combination of these results with our earlier findings of repellents and feeding deterrents against gypsy moth larvae (GML) in green ash foliage shows that the non‐host status of green ash to the highly polyphagous GML involves three orders of chemical defense: repellents, feeding deterrents and inhibitors of nutritional and developmental physiology. As the insect becomes sequentially exposed to these orders of defense, it incurs higher costs because the adverse effects become less reversible.
Inter‐ and intra‐population differences in the effects of temperature on postdiapause development of Delia radicum
Authors: Turnock W. J. , Boivin G. 
Published: October 2003

AbstractCanadian populations of D. radicum differ in their response to temperature during postdiapause development. Populations that are primarily of the early‐emerging type (≤256 DD04) (St‐Jean, Quebec; London, Ontario) have high values for the parameters describing this response: Rm= 12.7–13.3; Tm= 28.0–31.8 °C; Tσ= 10.3–14.2 (Rm, the maximum developmental rate at the temperature, Tm [ °C ] where the developmental rate is highest, and Tσ, the parameter which gives the shape of the truncated normal curve fitted to the data), a low degree‐day requirement for emergence (160–232 DD04), and may lack a developmental delay at temperatures above ca. 21 °C. Populations of the late‐emerging type (Kildare, Prince Edward Island) have low parameter values (Rm= 2.5, Tm= 19.3 °C; Tσ= 6.4), high degree‐day requirements (530 DD04), and a developmental delay at high temperatures. The parameters for the early‐emergers in the population from Winnipeg, Manitoba (74% early) were intermediate (Rm= 9.1, Tm= 27.1 °C, Tσ= 10.7, DD04= 246), but resembled the early rather than the late type. This population varied from 31 to 90% early type over a 10‐year period and the rate of postdiapause development at 20 °C was directly related to the percentage early. In the year with the most rapid development (90% early), development was significantly slower than in the populations from other locations with predominantly early populations, and the year with the slowest development (31% early) showed significantly faster development than that from Kildare, Prince Edward Island (100% late). Therefore the parameters for early and late types of development will not be accurate for use in mixed populations, and the parameters in mixed populations will change among years. Populations of D. radicum in North America and Europe (67 locations by years) varied from 0–100% early. At Winnipeg, the percentage early was directly related to the annual temperature accumulation (DD05) during the growing season. The calculation of developmental parameters for the early‐emergers of mixed populations provides a more accurate basis for estimating the times of first emergence and the first peak of emergence than parameters based on the whole population. Since postdiapause developmental rates vary both among and annually within locations, developmental models should be designed to include such variations.
Sequential sampling for adult coccinellids in wheat
Authors: Elliot N. C. , Michels G. J. , Kieckhefer R. W. , French B. W. 
Published: October 2003

AbstractAdult aphidophagous coccinellids are important predators of cereal aphids in wheat in the Great Plains of the United States for which sampling methods are needed to facilitate improved management. An equation relating the mean number of adult coccinellids per m2 in a wheat field to its variance was obtained using Taylor's power law. A sequential sampling procedure was developed to estimate the number of adult coccinellids per m2 with constant average statistical precision (standard error/mean). The procedure was constructed by an equation relating the number of adult coccinellids per m2 to the number of adult coccinellids per minute of counting incorporating into the Taylor's power law relationship. The procedure involves conducting a series of 1‐min counts while walking through a field at a constant velocity of 10 m per minute. After each 1‐min count sequential sampling stop‐lines are consulted to determine if the specified level of precision has been achieved. Two methods, a statistical procedure and comparison with independent data, were used to assess the consistency with which the specified level of precision was achieved by the procedure. Results indicated that observed precision was close to that specified by the user over a wide range of adult coccinellid density.
Nematode parasitism in a northern European drosophilid community
Authors: Gillis Jaklien E.M. , Hardy Ian C.W. 
Published: October 2003

AbstractMany factors may influence the structure of invertebrate communities. Among these is the presence of parasites which attack some or all members of a guild and potentially promote coexistence of competitor species. We assessed the prevalence of nematode (Allantonematidae) parasitism in Dutch woodland drosophilids (Diptera). Nematodes were found in 6 of the 18 drosophilid species sampled (percentage parasitism in parentheses): Drosophila phalerata (16%), D. kuntzei (5.1%), D. immigrans (0.5%), D. testacea (1.2%) and D. transversa (2.8%) were all parasitized by Howardula aoronymphium and D. subobscura (3%) was parasitized by Parazitylenchus diplogenus. This is the first report of nematode parasitism of D. immigrans and D. transversa. There were no important seasonal trends in percentage parasitism. We explored the consequences of nematode parasitism for individual drosophilids. Nematodes did not exert an important influence on the wing length (adult body size) of the drosophilids we sampled, but egg loads (fecundities) of female D. phalerata, D. subobscura and D. kuntzei were reduced by nematode parasitism. Parasitism rates were positively correlated with relative host abundance, in Dutch and other communities, suggesting that species diversity is promoted by a disproportionately high parasitism of more common host species.
Behavioral cues associated with oviposition by Trioza eugeniae
Authors: Luft Patrick A. , Paine Timothy D. 
Published: October 2003

Abstract Trioza eugeniae oviposited significantly more eggs on Syzygium paniculatum leaves free of eggs compared to leaves with pre‐existing eggs in a choice experiment, suggesting that females modify oviposition based on cues associated with the presence of eggs. In separate experiments, females avoided ovipositing on parts of leaves where eggs were present, but readily oviposited on areas of the same leaf without eggs. Epideictic pheromones are apparently not used by this species because females readily oviposited on areas of a leaf from which eggs had previously been removed. Females laid 57% of all their eggs along the margins of normal leaves, but also oviposited on artificial margins produced by cutting the leaves. The preference for natural margins over artificial margins was eliminated when the entire margin was coated with an antitranspirant compound to mask the damaged edge. These studies show that ovipositing psyllids respond both to the presence of eggs and to the suitability of the substrate.
Oviposition patterns of the pine weevil Hylobius abietis
Authors: Nordlander Göran , Nordenhem Henrik , Bylund Helena 
Published: October 2003

AbstractSpatial and temporal distributions of eggs laid by the pine weevil Hylobius abietis (L.) (Coleoptera: Curculionidae) were studied by taking root and soil samples around pine stumps on a clear‐cutting in central Sweden. In addition, first‐instar larvae migrating in the soil were sampled using traps baited with host‐odour. Eggs were found in the soil rather than in the bark of stump roots, which previously has been regarded as the usual oviposition site. Based on an oviposition experiment and additional field observations we conclude that eggs are laid in the bark of roots only when the surrounding material is likely to dry out. We suggest two explanations for why weevils oviposit mainly in the soil, although they are known to show stereotypic behaviour when inserting eggs in stump roots: (1) egg predation by other arthropods or by conspecifics is avoided, and (2) newly hatched pine weevil larvae are better than ovipositing females at locating suitable sites for larval feeding.
Diapause avoidance induced by low temperature in the yellow‐spotted longicorn beetle, Psacothea hilaris
Authors: Shintani Yoshinori , Ishikawa Yukio 
Published: October 2003

AbstractThe diapause‐averting effect of low temperature on pre‐diapause larvae was examined in the yellow‐spotted longicorn beetle, Psacothea hilaris. Larvae that had been reared under diapause‐inducing conditions (25 °C, L12:D12) were temporarily exposed to 10 °C for various periods, and returned to the initial condition. Diapause was not averted by chilling for 15 days irrespective of the age of the larvae at chilling. After a 30‐day chilling treatment, all of the 40‐ and 60‐day‐old larvae averted diapause, while diapause was averted in only one‐third of the 10‐ and 20‐day‐old larvae. None of the pre‐diapause larvae chilled for 60 days entered diapause irrespective of the age at chilling. With diapause avoidance, larvae that overwintered in earlier instars can start growing in earliest spring without any arrest; this phenomenon probably subserves the synchronization of larval development in a population.
Melon resistance to the aphid Aphis gossypii: behavioural analysis and chemical correlations with nitrogenous compounds
Authors: Chen Jian Q. , Rahbé Yvan , Delobel Bernard , Sauvion Nicolas , Guillaud Josette , Febvay Gérard 
Published: October 2003

AbstractIn the melon, the Vat (monogenic, dominant) resistance gene governs both an antixenotic reaction to the melon aphid Aphis gossypii Glover (Homoptera, Aphididae) and a resistance to non‐persistent virus transmission, restricted to this vector species. We investigated the behavioural features and tissue localisation of the antixenosis resistance by the electrical penetration graph technique (EPG, DC system). We also compared the chemical composition in amino compounds and proteins of the phloem sap collected from two isogenic lines of melon (Cucumis melo L.), carrying the Vat gene or not. All behavioural and chemical data indicated that this resistance is constitutive. EPG analysis clearly showed that access to phloem, although delayed by alterations in pathway activities, was not impaired in terms of frequency of access or initiation of feeding. The most striking feature was, however, a very reduced duration of ingestion from phloem of resistant plants, making this compartment one of the tissues where the effects of the Vat gene are unambiguously expressed. This was confirmed by clear differential activity of phloem extracts in artificial no‐choice bioassays. Chemical analyses have shown that phloem saps from the two isogenic lines were extremely similar in profiles of ninhydrin positive compounds, and contained a low total amount of free amino acids (less than 10 mM). Out of more than 40 distinguishable peaks in the chromatograms (protein and non‐protein amino acids, as well as small peptides), only five differentiated the two genotypes. Two of them were increased in the resistant genotype: glutamic acid and a major unknown peak, probably a non‐protein amino acid (different from β pyrazolyl‐alanine, a Cucumis‐specific amino acid). The three others were depressed in resistant plants, and included the sulphur amino acid cystine and a peptide peak partly composed of the cysteine‐containing peptide glutathione (reduced form). Sap collection also showed that phloem exudation rates, as well as total protein and glutathione levels, were depressed in phloem sap from resistant plants. Such data are all indicative of a modified phloem‐sealing physiology, linked to sulfhydryl oxidation processes, in plants carrying the Vat gene. The originality of the mechanism of Vat resistance to aphids is discussed.
Plant compensation, natural biological control, and herbivory by Aphis gossypii on pre‐reproductive cotton: the anatomy of a non‐pest
Authors: Rosenheim Jay A. , Wilhoit Lawrence R. , Goodell Peter B. , Grafton‐Cardwell Elizabeth E. , Leigh Thomas F. 
Published: October 2003

AbstractCrop plant compensation for herbivory and the population dynamics of herbivores are two key elements in defining an herbivore's pest status. We studied the dynamics of natural, unmanipulated populations of the aphid Aphis gossypii on seedling plantings of cotton, Gossypium hirsutum and Gossypium barbadense, over a 4‐year period in California's Central Valley. Aphid populations colonized all plantings, but reached densities in excess of 0.5 aphids/leaf during only one year (1991), when outbreaks occurred. Outbreak populations were, however, ephemeral; predation and parasitism suppressed aphid populations prior to the initiation of flower bud production, when cotton plant growth may become photosynthate‐limited. Effective natural biological control was observed despite the action of hyperparasitoids and the heavy mortality of immature parasitoids that occurred when predators consumed parasitized aphids.We conducted manipulative experiments during 1991 and 1992 to quantify the ability of pre‐reproductive G. hirsutum to compensate for aphid herbivory. In 1991 aphid populations in the high‐damage treatment reached densities as high as any observed naturally during the past 37 years. Damage symptoms were severe: leaf area was reduced by up to 58% and total above‐ground plant biomass was reduced by 45%. By the time of crop harvest, however, plants had compensated fully for the early damage in each of the three traits that define cotton's economic value: the timing of crop maturation, the yield of cotton fiber, and the quality of cotton fiber. Aphid feeding damage did, however, produce some changes in plant architecture that persisted throughout the growing season, including a decrease in the number of vegetative branches. In 1992 aphid populations and associated damage were much lighter, but the qualitative responses to herbivory were consistent with those observed in 1991. Plant compensation for early damage was complete for economically significant measures, and vegetative branch production was again suppressed in mature cotton plants. There was no evidence for a change in the suitability of G. hirsutum as a host plant for A. gossypii as a result of early damage (‘induced resistance’).We conclude that pre‐reproductive G. hirsutum, which has not yet begun strong allocations to reproductive structures or established architectural complexity, has retained effective means of compensating for herbivory. In contrast to other systems exhibiting strong compensation, G. hirsutum appears to compensate in part by enhancing apical dominance. The recognition of early‐season A. gossypii as non‐pests is critical to the sustainability of cotton production, because it will allow growers to forego pesticide applications that accelerate the evolution of pesticide‐resistance and disrupt natural communities of predators and parasitoids.
Biological control by two exotic parasitoids: eight‐year population dynamics and life tables of the arrowhead scale
Authors: Itioka Takao , Inoue Tamiji , Matsumoto Takashi , Ishida Norio 
Published: October 2003

AbstractTo determine the process of regulation of Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae) by the two introduced parasitoids, Aphytis yanonensis DeBach et Rosen and Coccobius fulvus (Compere et Annecke) (Hymenoptera: Aphelinidae), the temporal changes in the population density of U. yanonensis as well as the parasitism rates were monitored for eight years before and after the release of the two parasitoids in a Satsuma mandarin orange (Citrus unshiu Marc. (Rutaceae)) orchard. From 2–4 years after the release, the parasitism rate by C. fulvus gradually increased, eventually reaching 70%, while that by A. yanonensis showed a weak increase, remaining under 12%. During this period, the host density decreased to about 1/100 of the initial density. After the drastic decrease, the host density remained under 1/60 of the level previous to the release for at least 2 years with the populations of both parasitoids persisting. To estimate the ability of the two parasitoids to regulate the populations of U. yanonensis, life tables of U. yanonensis under natural conditions and predator/parasitoid‐exclusion (bagged) conditions were compared. It was demonstrated that C. fulvus and A. yanonensis impose about 70% mortality rate on the host at mature adult stages and about 30% on the host at immature adult stages. The results have strongly confirmed the high capability of the two parasitoids as biological control agents for U. yanonensis, which was suggested by earlier studies. However, contrary to those studies, the present study did not support the complementarity of the two parasitoids in regulating the host population, suggesting that the effectiveness of C. fulvus alone in regulating the host population at low levels.
Low‐vacuum electron microscopy of carabid chemoreceptors: a new tool for the identification of live and valuable museum specimens
Authors: Symondson W. O. C. , Williams I. B. 
Published: October 2003

AbstractHigh‐vacuum scanning electron microscopy, following coating of specimens with gold, produces high quality images that have proved invaluable for the study of insect sensilla. Unfortunately, the technique is essentially destructive, and cannot be used on live or valuable museum specimens. In particular, high‐vacuum scanning usually causes the collapse of the tips of the palps, interfering with any examination of the sensilla in this area. A new low‐vacuum technique is described that avoids these problems. Insect cuticle does not need to be coated with gold, thus avoiding damage to important specimens. Examples are given of scans of the palp tips of live carabid beetles, anaesthetised with CO2. It was shown that the technique could consistently display these tips in their natural convex state. In all, four types of sensilla were identified by low‐vacuum scans of the maxillary palps, and four further types on the terminal segment of the antennae, plus glandular openings. The antennae revealed a type of sensilla that has not previously been described on carabids. These sensilla showed clear structural differences between the two species studied, Pterostichus melanarius Illiger and P. niger Schaller (Coleoptera: Carabidae), and can be used as a diagnostic character for both fresh and dried specimens. The low‐vacuum technique can be recommended for examining valuable ‘type’ specimens without risk of damage.
Development of pheromone traps for control and monitoring of sweetpotato weevils, Cylas puncticollis and C. brunneus, in Uganda
Authors: Smit N. E. J. M. , Downham M. C. A. , Odongo B. , Hall D. R. , Laboke P. O. 
Published: October 2003

AbstractExperiments were carried out in Uganda to optimise pheromone traps for the African sweetpotato weevil species, Cylas puncticollis Bohe. and C. brunneus F. (Coleoptera: Apionidae). Various designs of funnel, water and sticky traps were compared and a 5‐l plastic jerry can trap was the most appropriate design for effectiveness and practicability. A solution of Omo detergent in water was found to be the most effective trapping agent. Fewer weevils were caught in red traps than in yellow, white, green or blue traps. Catches of C. puncticollis increased when the trap was raised above crop height, but catches of C. brunneus were unaffected. When marked weevils were dropped onto the trap, 36% of C. puncticollis and 23% of C. brunneus were captured, and, of weevils placed in the trap, 88% and 92%, respectively, of the two species remained overnight. Lures for the two species showed no significant loss in attractiveness after 8 weeks in the field, and chemical analysis showed 19% of the C. puncticollis pheromone and 72% of the C. brunneus pheromone remaining after this time. Summarizing, the following trap is presently recommended for monitoring/controlling African Cylas species: a 5‐l plastic jerry can trap of any colour with rectangular openings of 11×5 and 6×5 cm positioned 15 cm above the crop canopy, filled with 0.5 l Omo solution (1 g/1 l water), with 0.1 mg lures to be replaced every 8 weeks.
Evaluation of environmental and plant‐associated cues for nymphal settling preference by Trioza eugeniae
Authors: Luft Patrick A. , Paine Timothy D. 
Published: October 2003

AbstractExperiments were conducted to determine potential cues used by nymphs when they select the preferred abaxial side of a leaf. Nymphs most frequently settle and develop on the abaxial side of leaves. The degree of preference for the abaxial side was found to be reduced when a high density of nymphs were present, however. The orientation of leaves in a completely darkened chamber did not influence settling preference for the abaxial side, even when leaves were oriented abaxial side up. Coating both sides of a leaf with an antitranspirant compound did not prevent nymphs from preferring the abaxial side for settling. Similar results were obtained when leaves were dipped in pentane. These studies show that nymphs do not use gravity, color, light, or contact chemoreception when selecting suitable settling sites on a leaf.