bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of constant and fluctuating temperatures on sporulation and infection by the aphid‐pathogenic fungus Pandora neoaphidis
Authors: Shah P.A. , Aebi M. , Tuor U. 
Published: October 2003

AbstractLaboratory studies were performed to assess the importance of temperature on sporulation and infection by the aphid‐pathogenic fungus Pandora neoaphidis (Remaudière and Hennebert) Humber. Numbers of primary conidia discharged from mycelium formulated as alginate granules and unformulated mycelial mats were assessed, as well as infection of the potato aphid, Macrosiphum euphorbiae (Thomas) (Homoptera, Hemiptera, Aphididae), using culture plugs as inoculum sources. Sporulation from experiments at constant temperatures indicated the optimum temperature range was 10–20 °C for both mycelial preparations and there was no or very little sporulation at 30 °C. Infection of aphids kept at 15 °C was 34–50%, while infection at 25 °C was 11–44%. At 20 °C, 77–79% of aphids were infected. Under fluctuating temperature cycles, conidia numbers did not differ when mycelial preparations were maintained at 18–25 °C compared with 18–20 °C, but fewer conidia were recorded when preparations were exposed continuously to 18–30 °C. Infections of inoculated aphids kept for varying numbers of days at 18–25 °C varied between 24–47%, but only 3–32% of aphids were infected when exposed to a cycle of 18–30 °C for various times. Unformulated mycelial mats of P. neoaphidis appear to be superior to forumlated alginate granules for use in experimental greenhouse and field trials, since temperature stability is similar for both materials but mycelial mats are much easier to produce.
Costs of secondary parasitism in the facultative hyperparasitoid Pachycrepoideus dubius: does host size matter?
Authors: Grandgirard Julie , Poinsot Denis , Krespi Liliane , Nénon Jean‐Pierre , Cortesero Anne‐Marie 
Published: October 2003

AbstractAlthough hyperparasitism frequently occur in parasitic insects, many aspects of this strategy remain unknown. We investigated possible fitness costs of hyperparasitism as influenced by host size. Our study was conducted with the facultative hyperparasitoid Pachycrepoideus dubius Ashmead (Hymenoptera: Pteromalidae), which parasitizes host species differing greatly in size. We compared some fitness traits (level of successful parasitism, development time, sex ratio and offspring size) of P. dubius developing on large secondary/primary (Delia radicum L. (Diptera: Anthomyiidae)/Trybliographa rapae Westwood (Hymenoptera: Figitidae)) or small secondary/primary host species (Drosophila melanogaster L./Asobara tabida Nees (Hymenoptera: Braconidae)). In no‐choice and choice experiments, P. dubius was able to develop on different stages of T. rapae (L2 (endophagous), L4 (ectophagous), and pupae) but that it preferred to parasitize unparasitized D. radicum pupae over pupae parasitized by T. rapae. Furthermore, in P. dubius, hyperparasitism was associated with fitness costs (lower level of successful parasitism, smaller adult size) and these costs were greater on the smallest host complex. We hypothesize that the size of D. melanogaster pupae parasitized by A. tabida may be close to the suboptimal host size for P. dubius beneath which the costs of hyperparasitism make this strategy nonadaptive. Hyperparasitism in terms of trade‐offs between host quality and abundance of competitors is discussed.
The chemical world of crucivores: lures, treats and traps
Authors: Renwick J. Alan A. 
Published: October 2003

AbstractThe host ranges of several insects that are specialists on crucifers (Brassicaceae) are closely linked to the presence of glucosinolates in these plants. These glycosides often serve as stimulants for oviposition and/or feeding, while their volatile hydrolysis products may be attractants for several species. However, many crucifers produce additional secondary compounds that act as repellents, deterrents or toxins, which protect them from these insects. The widely different responses of the various crucifer specialists to these compounds reflect different degrees of adaptation to the plant defenses. Thus native insects are often unable to survive on introduced plants, although the ubiquitous glucosinolates may trigger oviposition ‘mistakes’. The success of highly invasive cruciferous weeds may be due in part to a lack of local herbivore adaptation to unique chemical constituents of these plants. However, the concentrations of secondary chemicals vary with season, environmental conditions, and geographical location. This could mean that windows of opportunity exist for utilization of introduced plants. Recent studies with garlic mustard, Alliaria petiolata, and wintercress, Barbarea vulgaris, in the USA have shown that these introduced plants are resistant to the native butterfly, Pieris napi oleracea. The combined effects of a flavone glycoside and a unique butenenitrile glycoside in the garlic mustard appear to be responsible for blocking feeding by this insect. Barbarea vulgaris is also resistant to the diamondback moth, Plutella xylostella, in North America and to the flea beetle, Phyllotreta nemorum, in Europe. Comparative studies indicate that common resistance mechanisms are involved and bioassays have been developed to elucidate the chemical nature of this resistance.
Host specificity and host recognition in a chemically‐defended herbivore, the tenthredinid sawfly Rhadinoceraea nodicornis
Authors: Barker Alison , Schaffner Urs , Boevé Jean‐Luc 
Published: October 2003

AbstractThe sawfly Rhadinoceraea nodicornis Konow (Hymenoptera: Tenthredinidae) is a member of a closely related group of species, the tribe Phymatocerini, which feed on the Liliales and Ranunculales. It is known to sequester steroid alkaloids from its host plants, species in the genus Veratrum (Liliales: Melanthiaceae), and to use them as a defence against predators. There are known chemical relationships between the hosts of R. nodicornis and hosts of related sawfly species. We tested whether the R. nodicornis larvae would accept hosts of closely‐ and more distantly‐related sawflies, but found that they accepted only plant species in the genus Veratrum. This specificity was apparently innate, as it was independent of early larval experience. A feeding bioassay showed that the steroid alkaloids from Veratrum nigrum were phagostimulatory for R. nodicornis larvae, suggesting that they may be involved in host recognition. We discuss the possibility that the evolution of recognition of specific compounds may represent the mechanism of host radiation within the Phymatocerini.
Incidence of apple fruit and leaf surface metabolites on Cydia pomonella oviposition
Authors: Lombarkia Nadia , Derridj Sylvie 
Published: October 2003

AbstractWater soluble metabolites identified from surfaces of apple tree fruit and leaf stimulate oviposition in Cydia pomonella L. The effects of two artificial blends of primary metabolites representing fruit and leaf surfaces, respectively, and of components within the blends were examined on egg‐laying after two time periods: 3 min and 25 min of darkness. An artificial mixture of six metabolites, viz., three sugar alcohols (sorbitol, quebrachitol, and myo‐inositol) and three sugars (glucose, fructose, and sucrose) did stimulate egg‐laying. Fructose, sorbitol, and myo‐inositol are important components of the stimulatory blend. Contact durations may induce variations in egg‐laying responses. After 3 min of darkness, there were no differences in numbers of females laying eggs nor in the numbers of eggs laid on cloths treated with the complete blends and the controls. There were, however, clear effects of groups of compounds and of individual compounds. Reduced blends without sugars and sugar alcohols were in many cases significantly less stimulatory than the complete blends and the controls. After 25 min of darkness, the proportions of females laying eggs as well as the numbers of eggs were higher after treatment with the complete blends than on the controls. The proportions of females laying eggs on cloths treated with the reduced blends were rather similar to the controls, whereas there were still significant effects on the numbers of eggs laid after treatment with reduced blends derived from fruits but not from leaves.
Xylem ingestion by winged aphids
Authors: Powell Glen , Hardie Jim 
Published: October 2003

AbstractWhen aphids and their host plant are incorporated in a DC electrical circuit, phloem and xylem ingestion register as separate waveforms of the electrical penetration graph (EPG) signal. Aphids are primarily phloem feeders; xylem ingestion is seldom reported but can be induced experimentally by fasting the insects in desiccating conditions. In experiments with the black bean aphid, Aphis fabae Scop., young winged (alate) and unwinged (apterous) virginoparous adults were collected from their natal host plants (broad bean, Vicia faba L.) and allowed 3‐h continuous EPG‐recorded access to V. faba seedlings. Several aphids (47% of both morphs) showed ingestion from phloem sieve elements. Alate aphids also showed frequent xylem ingestion (60% of individuals), but no apterous aphids exhibited this activity. The EPG technique involves attachment of a fine gold wire electrode to each insect, a process that may affect normal behaviour at the plant surface. However, when the technique was modified to monitor the stylet activities of freely‐settled aphids, high levels of xylem ingestion by alates were also recorded. The results suggest that the developmental physiology of winged aphids somehow predisposes them to xylem ingestion, possibly as a result of dehydration during the teneral period. Alate aphids may reduce their weight by fasting before take‐off, giving aerodynamic benefits, but making rehydration, via xylem uptake, a priority following plant contact.
The effect of different plant nutrient regimes on the aphid Macrosiphum euphorbiae growing on petunia
Authors: Jansson Johanna , Ekbom Barbara 
Published: October 2003

AbstractThree experiments were conducted to study how nutrient content of the host plant, Petunia axillaris hybrida Villm. Grandiflora Group, affects the performance of Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae). Aphid performance was analysed in relation to plant nutrient levels and the ratio of nitrogen to potassium (N/K). Phosphorus (P) had a positive effect on several parameters of aphid performance. Both P and K were associated with a short development time but a strong correlation between P and K content made it impossible to detect their relative importance. In one experiment aphid performance was significantly lower on unfertilised plants with low N content, suggesting a positive effect of N. A high N/K ratio did not, in general, increase aphid performance. The complexity of plant nutrient content on aphid performance suggests that not only nutrient levels but also ratios of nutrients must be considered.
Do fecal shields provide physical protection to larvae of the tortoise beetles Plagiometriona flavescens and Stolas chalybea against natural enemies?
Authors: Nogueira‐de‐Sá Flávia , Trigo José Roberto 
Published: October 2003

AbstractDuring their larval phase, Plagiometriona flavescens (Boheman, 1855) and Stolas chalybea (Germar, 1824) (Chrysomelidae: Cassidinae), carry masses of feces and exuviae on their back called fecal shield, and it is suggested to protect larvae against natural enemies. We investigated if the physical barrier provided by the shield plays any role in the defense of these larvae. We conducted a field experiment checking the mortality of larvae of both species with their natural shields substituted by an artificial shield, with shields removed and with their shields intact. Mortality controls for each of the 3 shield treatments were carried out on host plants protected against natural enemies. On both species we observed that larvae with their shields intact had a significant lower mortality proportion than larvae with artificial shields or without shields. Control larvae on protected plants had low mortality. Our results agree with literature data, showing that fecal shields do not provide a physical protection to larvae but are important in their defense, probably due to the chemicals present in them.
Evaluation of dietary effects of transgenic corn pollen expressing Cry3Bb1 protein on a non‐target ladybird beetle, Coleomegilla maculata
Authors: Duan Jian J. , Head Graham , McKee Michael J. , Nickson Thomas E. , Martin John W. , Sayegh Fouad S. 
Published: October 2003

AbstractA transgenic corn event (MON 863) has been recently developed by Monsanto Company for control of corn rootworms, Diabrotica spp. (Coleoptera: Chrysomelidae). This transgenic corn event expresses the cry3Bb1 gene derived from Bacillus thuringiensis (Berliner), which encodes the insecticidal Cry3Bb1 protein for corn rootworm control. A continuous feeding study was conducted in the laboratory to evaluate the dietary effect of MON 863 pollen expressing the Cry3Bb1 protein on the survival, larval development, and reproductive capacity of the non‐target species, Coleomegilla maculata DeGeer (Coleoptera: Coccinellidae). First instar C. maculata (less than 24 h old) and newly emerging adults (less than 72 h old) were fed individually on a diet mixture containing 50% of MON 863 pollen, non‐transgenic (control) corn pollen, bee pollen (a component of normal rearing diet), or potassium arsenate‐treated control corn pollen. In the larval tests, 96.7%, 90.0%, and 93.3% of C. maculata larvae successfully pupated and then emerged as adults when fed on MON 863 pollen, non‐transgenic corn pollen, and bee pollen (normal rearing) diets, respectively. Among the larvae completing their development, there were no significant differences in the developmental time to pupation and adult emergence among the transgenic corn pollen, non‐transgenic corn pollen, and bee pollen diet treatments. All larvae fed on arsenate treated corn pollen diet died as larvae. For tests with adults, 83.3%, 80.0%, and 100% of adult C. maculata survived for the 30 days of the test period when reared on diets containing 50% of MON 863 pollen, non‐transgenic corn pollen, and bee pollen respectively. While the adult survival rate on MON 863 pollen diet was significantly less than that on the bee pollen diet, there was no significant difference between the MON 863 and non‐transgenic corn pollen treatments. During the period of adult testing, an average of 77, 80, and 89 eggs per female were laid by females fed on the MON 863 pollen, control corn pollen, and bee pollen, respectively; no significant differences were detected in the number of eggs laid among these treatments. These results demonstrate that when offered at 50% by weight of the dietary component, transgenic corn (MON 863) pollen expressing Cry3Bb1 protein had no measurable negative effect on the survival and development of C. maculata larvae to pupation and adulthood nor any adverse effect on adult survival and reproductive capacity. Relevance of these findings to ecological impacts of transgenic Bt crops on non‐target beneficial insects is discussed.
Increase in cereal stem borer populations through partial elimination of natural enemies
Authors: Kfir Rami 
Published: October 2003

AbstractAn insecticide exclusion method was used to evaluate the effect of parasitoids on level of infestation by the stem borers, Busseola fusca (Fuller) and Chilo partellus (Swinhoe), in grain sorghum. In field trials conducted at Brits and at Delmas, South Africa, a selective organophosphate insecticide, dimethoate, was applied twice weekly at each site to three subplots whereas three other identical subplots served as controls. Twelve plants were randomly selected from each subplot at weekly intervals and removed from the field. In the laboratory all plants were dissected to record borer infestation. In order to determine parasitism levels egg batches were kept in Petri dishes and all borer larvae and pupae were kept individually in vials until either parasitoids or moths emerged. At Brits ca. 97% of borers were C. partellus and 3% B. fusca, whereas at Delmas 37.5% were C. partellus and 62.5% B. fusca. The most abundant parasitoids of B. fusca were Cotesia sesamiae (Cameron) and Bracon sesamiae Cameron. The dominant parasitoids of C. partellus at both sites were C. sesamiae, Stenobracon spec., Dentichasmias busseolae Henrich and Pediobius furvus (Gahan). No egg parasitoids were found. At both sites, infestation levels in the sprayed plots were significantly higher than in the untreated plots. On the other hand, parasitism levels of borers in the unsprayed plots were significantly higher than in the treated plots. It was concluded that the higher infestation level of sorghum by stem borers in the sprayed plots was because of partial elimination of parasitoids and possibly other natural enemies by the pesticide.
Influence of pollen origin on performance of Bombus terrestris micro‐colonies
Authors: Génissel A. , Aupinel P. , Bressac C. , Tasei J.‐N. , Chevrier C. 
Published: October 2003

AbstractThe effect of the floral origin of pollen on the reproductive success of Bombus terrestris Latrum bumblebee (Apidae: Bombinae), was investigated by feeding micro‐colonies of queenless workers with different pollen types. We used a commercial pollen blend and three unifloral pollens, Prunus, Salix, and Taraxacum. Among the unifloral pollens, pollen quality did not influence egg production, but did influence egg laying delay and larval growth. The quality of pollens varied according to their protein content and protein efficacy (PE). Pollen from Prunus (27.5% w/w protein, PE = 10) resulted in the largest number of progeny, whereas Taraxacum (17.2% w/w protein, PE = 0) did not result in any offspring, due to high oophagy and larval ejection. Salix (20% w/w protein) and the blend (222.8% protein) diets gave rise to intermediate reproductive outputs. When pollen quality was sufficient for larval growth, the fitness of the male offspring was not affected over the range of the experimental diets. Our results suggest that quantitative and qualitative variations of pollen proteins have considerable influence on the reproductive success of bumblebees. Furthermore, larval growth has specific nutritive demands not provided by Taraxacum pollen, which is missing two essential amino acids.
Phospholipid composition and pheromonal activity of nuptial secretion of the male German cockroach, Blattella germanica
Authors: Kugimiya Soichi , Nishida Ritsuo , Kuwahara Yasumasa , Sakuma Masayuki 
Published: October 2003

AbstractAs a part of the sequential courtship behavior of the German cockroach, Blattella germanica, females feed on the nuptial secretion from the male tergal glands. The pheromonal secretion, consisting mainly of oligosaccharides and phospholipids, strongly elicits a feeding response in virgin females. The phospholipids were composed of phosphatidylethanolamine and phosphatidylcholine. Their fatty acid compositions were determined by chromatographic and enzymatic methods. Although an authentic blend of phospholipids (1,2‐dioleoylphosphatidylethanolamine and 1,2‐dioleoylphosphatidylcholine) showed a marginal phagostimulant activity, addition of the blend to an authentic blend of oligosaccharides (maltose and maltotriose) strongly enhanced the activity to nearly the level of the crude extract. These results indicate that the nuptial feeding behavior is elicited by a synergistic action between phospholipids and oligosaccharides.
Are There A Priori Concepts?
Authors: Austin J. L. , Urmson J. O. , Warnock G. J. 
Published: October 2003

Abstract
Austin discusses the existence, origin, and resemblance of concepts, primarily by discussing the meaning of ‘concept’ and ‘universal’. He argues that, although sometimes it may not be harmful to talk about concepts, we neither understand the meaning of ‘concept’, nor the meaning of ‘acquiring and possessing concepts’, nor a view of concept resemblance as non-sensuous acquaintance or awareness, challenging philosophers who couch their theories in such terms to illuminating them first.
How to Talk
Authors: Austin J. L. , Urmson J. O. , Warnock G. J. 
Published: October 2003

Abstract
Concerned with the question of whether descriptions of identity, i.e. describing X as Y, amount to the same as statements of identity, i.e. stating that X equals Y. Austin characteristically tackles this question by investigating into the nature of a number of relevant speech acts, such as ‘calling’, ‘describing’, and ‘stating’. He concludes negatively that none of the speech acts discussed can be safely used in philosophy in a general way. However, the construction of models of speech situations reveals their underlying complexity: such models are plainly too complicated to accommodate the standard subject-predicate or class-membership models that a straightforward answer to the question raised in this paper would depend on.
The Line and the Cave in Plato's Republic
Authors: Austin J. L. , Urmson J. O. , Warnock G. J. 
Published: October 2003

Abstract
A reconstruction based on previously unpublished notes, of Austin’s views of the Line and Cave allegories in Plato’s Republic. In these drafts, Austin discusses the prominent issues that arise in the context of Plato’s Line allegory, e.g. the questions of division and continuity, and shows how the different stages in the Cave allegory correspond to individual sections of the Line.
Factors Affecting the Process of Collaborative Product Development: A Study of UK Manufacturers of Information and Communications Technology Products
Authors: Littler Dale , Leverick Fiona , Bruce Margaret 
Published: October 2003

Product development is inherently risky, particularly when new technology is involved. Although collaborative product development is promoted as a means for reducing or at least sharing risk, such partnerships present their own challenges. Collaboration can also accentuate many of the risks inherent in product development. For example, any product development project requires effective communication among development team members. In a collaborative effort, this challenge is even greater because the development team spans organizational as well as functional boundaries.Dale Littler, Fiona Leverick, and Margaret Bruce describe the results of a survey that was conducted to identify the risks and benefits of collaborative product development as well as the key success factors for such relationships. The main reasons cited for collaborating on product development projects include satisfying customer requirements, taking advantage of market opportunities for which the firm lacks necessary skills and technical expertise, and responding to changes in technology. Other reasons for collaboration include reducing the cost and risk of product R&D, improving time to market, and gaining access to new markets.In addition to the risks associated with product development by a single company, the partners in a collaborative effort face several other challenges. For example, one company might gain inside knowledge of its partner's unique skills and expertise. Despite the cost and time involved in managing the collaboration, such a relationship usually results in less direct control over product development. Of particular concern are the difficulties of coordinating the divergent management styles and budgeting processes of the collaborating firms.Collaboration requires frequent communication among all involved parties. The likelihood of success is greatly enhanced by the presence of a product or collaboration champion. Other success factors include ensuring that partners contribute as expected, creating the perception of equal benefits among partners, and building trust between partners. Firms that are more experienced with collaboration also cite the importance of flexibility in corporate systems and management style, fit with existing businesses, and the choice of a partner.