bluuebunny/crossref_metadata_2025_split huggingface dataset:
Venturia canescens parasitizing Galleria mellonella and Anagasta kuehniella: differing suitability of two hosts with highly variable growth potential
Authors: Harvey Jeffrey A. , Vet Louise E.M. 
Published: October 2003

Abstract Venturia canescens (Grav.) (Hymenoptera: Ichneumonidae) is a solitary larval koinobiont endoparasitoid, ovipositing in several larval instars of different pyralid moth species that are pests of stored food products. After oviposition, the host larva continues to feed and grow for at least several days, the precise time doing so depending on the stage attacked. We examined the relationship between host stage and body mass on parasitoid development in late second to fifth instars of two hosts with highly variable growth potential: the wax moth, Galleria mellonella (L) and the flour moth, Anagasta kuehniella (Zeller)(Lepidoptera: Pyralidae). G. mellonella is the largest known host of V. canescens, with healthy larvae occasionally exceeding 400mg at pupation, whereas those of A. kuehniella rarely exceed 40 mg at the same stage. Parasitoid survival was generally higher in early instars of G. mellonella than in later instars. By contrast, percentage adult emergence in A. kuehniella was highest in late fifth instar and lowest in late second instar. A. kuehniella was the more suitable host species, with over 45% adult emergence in all instars, whereas in G. mellonella we found less than 35% adult emergence in all instars. Adult parasitoid size increased and egg‐to‐adult development time decreased in a host size‐ and instar‐specific manner from A. kuehniella. The relationship between host size and stage and these fitness correlates was less clear in G. mellonella. Although both host species were parasitized over a similar range of fresh weights, the suitability weight‐range of A. kuehniella was considerably wider than G. mellonella for the successful development of V. canescens. However, in hosts of similar weight under 5 mg when parasitized, larger wasps emerged from G. mellonella than from A. kuehniella. Parasitoid growth and development is clearly affected by host species, and we argue that patterns of host utilization and resource acquisition by parasitoids have evolved in accordance with host growth potential and the nutritional requirements of the parasitoid.
The relation between dispersal and survival of Lobesia botrana larvae and their density in vine inflorescences
Authors: Torres‐Vila Luis M. , Stockel Jacques , Roehrich Roger , Rodríguez‐Molina M. Carmen 
Published: October 2003

AbstractDispersal and survival of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) larvae in a simulated first generation and the relationship with their density on vine inflorescences were studied under field conditions. Artificial infestations with neonate larvae were conducted at densities of 5, 10, 15, 20 and 25 individuals per vine inflorescence. Larvae had a considerable dispersal capacity on the vine espalier and were able to reach several inflorescences around those artificially infested. Dispersal downwards (63.1%) was significantly more frequent than upwards (36.9%), probably because larvae move down the vine plant using silk threads. However, the fact that there was upwards dispersal provides evidence that larvae are capable of active locomotion upwards on the vine plant structure. Mean distances covered by larvae ranged between 10 and 30 cm, with a maximum as far as 45 cm. The longest displacements were not associated with the downward dispersal. The maximum distance covered by larvae was positively correlated with larval density. Mean distance and larval density were not correlated, but mean distances covered at high larval densities were significantly higher than at low densities. At higher larval densities, the proportion of larvae which established in the artificially infested inflorescences decreased whereas the proportion of dispersing individuals increased. However, as a result of the balance between establishment and dispersal, larval survival did not differ significantly among larval densities (26–44%). The results obtained suggest that larval dispersal must be taken into account when preimaginal stages are sampled to determine whether damage thresholds are reached in an integrated pest management program.
Fitness consequences of ovicide in a parasitoid wasp
Authors: Mayhew Peter J. 
Published: October 2003

AbstractOvicide, superparasitism and host rejection are alternative reproductive tactics facing female parasitoid wasps encountering an already‐parasitized host. Superparasitism is simply the addition of an egg or a clutch of eggs by the secondary parasitoid, but under ovicide the primary clutch is removed or destroyed. Host rejection occurs if the wasp leaves without laying a clutch.The ectoparasitoid Laelius pedatus (Say) (Hymenoptera: Bethylidae) performs ovicide in this situation. Clutch manipulation experiments show that secondary clutches suffer high mortality in competition with primary clutches, which increases with increasing time delay between clutches. Primary clutches however suffer little in competition with secondary clutches, even if there is minimal time delay between clutches. These data suggest that the offspring of ovicidal females are substantially fitter than the offspring of superparasitizing females.Handling time and clutch size do not differ significantly between first (sole) parasitoids and second (ovicidal) parasitoids. The same is true for offspring survival and development time. However, offspring of second females are slightly smaller. This suggests that parasitized and unparasitized hosts are resources of similar quality when ovicide is performed.These data strongly support the predictions of evolutionary models of ovicide. They may also give some insight into the taxonomic distribution of ovicide in parasitoids.
Semiochemistry of aposematic seed bugs
Authors: Aldrich J. R. , Leal W. S. , Nishida R. , Khrimian A. P. , Lee C.‐J. , Sakuratani Y. 
Published: October 2003

Abstract(E)‐2,7‐Octadienyl acetate and (E)‐2‐octenyl acetate (1:10 by volume) were identified as a pheromone attractive to both sexes of the lygaeid bug, Tropidothorax cruciger. In a parallel investigation of Neacoryphus bicrucis (Lygaeidae), (E,E)‐2,4‐hexadienyl acetate and phenethyl acetate (≈9:1) were identified from males, and found attractive to both sexes of adults in the field plus a tachinid fly parasitoid of the bugs. In N. bicrucis, the pheromone was clearly shown to come from the tubular accessory glands of the metathoracic scent gland; this evidence, plus earlier literature reports for other species, indicate that male lygaeids are the pheromone emitters. In another lygaeid, Oncopeltus fasciatus, 2‐isobutyl‐3‐methoxypyrazine was identified in the cardiac glycoside‐laden fluid sequestered from milkweed hosts and expelled by these bugs when they are attacked. Alkyl methoxypyrazines are warning odorants associated with poisonous insect secretions, and their presence in O. fasciatus indicates that the plant‐derived chemical defense of lygaeines is more elaborate than previously appreciated.
Resistance to the pink potato aphid, Macrosiphum euphorbiae, in two accessions of Lycopersicon hirsutum f. glabratum
Authors: Musetti Luciana , Neal Jonathan J. 
Published: October 2003

AbstractAccessions PI 126449 and PI 134417 of wild tomato, Lycopersicon hirsutum f. glabratum C.H. Mull, were assessed for resistance to the pink potato aphid, Macrosiphum euphorbiae (Thomas). Aphid populations under field and greenhouse conditions were significantly lower on the L. hirsutum f. glabratum plants compared to L. esculentum. Removal of trichome glands and exudates by wiping the leaf surface resulted in a dramatic decrease in aphid mortality. Compared to L. esculentum, aphid behavior on the L. hirsutum f. glabratum plants was characterized by 40 to 52% abandonment, delay in time for first probe, reduction of number and duration of probes and decrease in the total proportion of time probing. Removal of the trichomes reduced the percentage of abandonment and increased the total proportion of time probing. Density and type of glandular trichomes varied among plant lines and on adaxial and abaxial leaf surfaces within a line, particularly for the L. hirsutum f. glabratum plants. PI 134417 was, in general, more resistant to the aphids than PI 126449.
Test for predation effects of single versus multiple species of generalist predators: spiders and their insect prey
Authors: Riechert S.E. , Lawrence K. 
Published: October 2003

AbstractThe prediction that single spider species (as exemplary generalist predators) limit associated prey populations to the same extent that species assemblages do was tested in a well controlled and replicated old field experiment involving the following treatments: (1) the natural spider assemblage (2) a numerically prominent web building spider, (3) a numerically prominent wandering spider, (4) a biomass prominent web‐builder, and (5) a biomass prominent wandering spider. Pest insect numbers were significantly higher in spider removal controls than in any spider treament over the four month period of the study, both in terms of total numbers and per spider effects. The individual spider species, in general, showed reduced prey limitation effects relative to that of the spider assemblage, though the magnitudes of these differences were small when compared to those exhibited between the various treatments and the spider removal control. When insect numbers were partitioned according to taxa, no treatment was found to have limited the predaceous insects nor the phytophagous hemipterans. All treatments, however, showed significant limiting effects on the phytophagous homopterans, coleopterans, and dipterans in the old field system, and other taxa were significantly reduced in at least one treatment in addition to the spider assemblage as a whole.
Toxicity of acephate to larvae of gypsy moth as a function of host plant and bioassay method
Authors: Moldenke Alison F. , Berry Ralph E. , Miller Jeffrey C. , Wernz James G. 
Published: October 2003

AbstractWe examined toxicity of acephate to third‐instar gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), under different conditions of administration method, availability of food to larvae during bioassay, host plant, and activity of detoxifying enzymes. Larvae that had been fed field‐collected foliage of white alder (Alnus rhombifolia Nutt.) were less susceptible 48 h after treatment with topically applied acephate if they were allowed to continue feeding on foliage during the bioassay period (LD50= 60.6 μg/g larva) than if they were not (LD50= 13.5 μg/g larva). All surviving larvae were replaced on their original food plant after the 48‐h bioassay; of these, 14.4% of the larvae not fed during treatment died before pupation, compared with 1.3% of the larvae fed alder during treatment. The LD50 obtained for topically treated larvae reared and treated on Douglas‐fir, Pseudotsuga menziesii (Mirb.) Franco, (51.1 μg/g larva) was comparable to that obtained for larvae fed alder (60.0 μg/g larva) throughout treatment. Larvae treated orally with acephate, however, were slightly more susceptible when reared on Douglas‐fir (LC50, 20.3 ppm) than when reared on alder (LC50, 27.0 ppm). Post‐treatment mortality in orally treated larvae was 10.3% in those fed alder and 9.5% in those fed Douglas‐fir. Higher cytochrome P‐450 activities in larvae reared on Douglas‐fir apparently did not enhance tolerance to acephate. Both sexes of orally treated larvae took significantly longer to pupate than did controls on both foliage types, as did topically treated males fed Douglas‐fir. Pupal weight generally was slightly, but not always significantly, higher in treated than untreated larvae under all dietary and treatment regimes.
A behavioural study to help clarify how undersowing with clover affects host‐plant selection by pest insects of brassica crops
Authors: Finch S. , Kienegger M. 
Published: October 2003

AbstractLaboratory and field‐cage tests were done to determine how undersowing brassica plants (Brassica oleraceae L. and B. rapa L.) (Cruciferae) with subterranean clover (Trifolium subterraneum L.) (Papilionaceae) affected host‐plant selection by eight pest insect species of brassica crops. The pest species tested were Pieris rapae (Lepidoptera: Pieridae) (the small white butterfly), Pieris brassicae (Lepidoptera: Pieridae) (the large white butterfly), Delia radicum (Diptera: Anthomyiidae) (the cabbage root fly), Phaedon cochleariae (Coleoptera: Chrysomelidae) (the mustard beetle), Plutella xylostella (Lepidoptera: Yponomeutidae) (the diamond‐back moth), Evergestis forficalis (Lepidoptera: Pyralidae) (the garden‐pebble moth), Mamestra brassicae (Lepidoptera: Noctuidae) (the cabbage moth) and Brevicoryne brassicae (Hemiptera: Aphididae) (the cabbage aphid). In all tests, except two in which the brassica plants were about three times as high as the clover background, 39%–100% fewer of the pest insect stage monitored were found on host plants presented in clover than on those presented in bare soil. Contrary to claims supporting the ‘enemies hypothesis’, differences in colonization alone appeared sufficient to account for the lower numbers of insects found when host plants are undersown with clover. To be effective in reducing plant colonization, the clover must cover 50%, and preferably more, of the vertical profile of the crop plants. As clover used as an undersown crop often has to be cut to make it less competitive with the main brassica crop, temporal aspects of the condition of the clover during critical periods of pest activity need to be recorded carefully before concluding that undersowing does not produce the effect desired against certain pest species under field conditions. The effective clover barrier is like any other treatment, if it is not present at the appropriate time it cannot be expected to reduce pest insect numbers.
Oviposition of resistant and susceptible strains of Drosophila melanogaster in the presence of deltamethrin
Authors: Renou Michel , Henninot‐Rodes Emmanuelle , Delorme Robert , Augé Danielle , Touton Philippe 
Published: October 2003

AbstractOviposition of three strains of Drosophila melanogaster in the presence of deltamethrin was observed. These strains had different levels of physiological susceptibility to deltamethrin. Two‐choice tests were conducted with couples of flies in petri‐dish arenas containing two oviposition dishes. On the first day of the experiment, females were given a choice between a treated oviposition dish and an untreated control dish. On the second day of the experiment, two control oviposition dishes were given to females. Although individual females showed a tendency to aggregate their eggs in one of the dishes, control experiments demonstrated an overall equal distribution of eggs between the dishes. When one of the two oviposition dishes in the arena was treated with deltamethrin, the percentage of females ovipositing and the mean number of eggs laid by females were reduced, compared with control arenas. Females avoided the treated oviposition dish and laid significantly more eggs on the control dish. Furthermore, when the deltamethrin concentration was increased on the first day, female flies postponed their oviposition and laid significantly more eggs on the second day. The resistant strain, SR, demonstrated the same capacity to select the untreated site for oviposition as the susceptible strain, but it showed a smaller oviposition reduction and egg retention. The relationship between physiological and behavioural susceptibility to deltamethrin is discussed.
Response of the pollen beetle Meligethes aeneus to volatiles emitted by intact plants and conspecifics
Authors: Ruther Joachim , Thiemann Karsten 
Published: October 2003

AbstractThe response of the pollen beetle Meligethes aeneus Fab. (Coleoptera, Nitidulidae) to the volatiles of undamaged plants and conspecifics was tested in a Y‐tube‐olfactometer‐bioassay. Beetles that had hibernated preferred significantly the volatiles emitted by their most important host plant, oilseed‐rape (Brassica napus L. ‘Lorar’) in the early bud‐stage. However, the odour emitted by rye (Secale cereale L.), tomato plants (Solanum lycopersicum L.), and yarrow (Achillea millefolium L.) were also attractive when tested against the corresponding growing‐medium. Dock plants (Rumex obtusifolius L.) and touch‐me‐not (Impatiens parviflora L.) possessed no attractive properties. When tested against each other, oilseed‐rape was preferred significantly by M. aeneus above all other plants, with the exception of tomato. The results indicate that M. aeneus is able to locate its host plant by olfactory stimuli in the early bud‐stage, i.e. in that stage in which the infestation begins in the field and when the typical yellow colour and floral scent of oilseed‐rape are absent.Female pollen beetles avoided significantly the volatiles emitted by female conspecifics and an ether extract of conspecifics of mixed sex, while volatiles from males had no significant effect on females. Furthermore, males showed no preferences when responding to conspecific odour in the olfactometer. These results suggest the existence of an epideictic pheromone for M. aeneus.
Obituary
Authors: Parella M.P. 
Published: October 2003

AbstractWe received the sad news that our Editor Dr Sean S. Duffey passed away unexpectedly on 21 May 1997. Dr Duffey has been serving the journal since 1994 with great enthusiasm. Many authors have profited from his positive criticisms, which were always accompanied by detailed suggestions as to how their manuscripts could be improved. Because of his thorough reviews of papers on various topics, Dr Duffey has made an outstanding contribution to the journal. Dr Duffey's views and helpfulness well be missed, not only by his family, friends and colleagues, but also by us and the readership of this journal. An Obituary for Dr Duffey by a close colleague is published below.The Executive Editors
Distribution of faeces of the German cockroach, Blattella germanica, in a new refuge
Authors: Stejskal Václav 
Published: October 2003

AbstractThe patterns of faeces deposition in glass arenas with three groups of Blattella germanica L. during colonization of new refuges were recorded. The individual positions of more than 17,500 faeces were recorded. The average daily rate of faeces excretion per adult was 9.6 in males, 9.1 in non‐gravid females and 2.7 in gravid females. Significant differences of faeces accumulation at various sites of the arena were found. In all three groups, mean density of faeces decreased in the following order: shelter, edges of arena, area around shelter, remainder of open area. The faeces were not accumulated more significantly at food and water sources than within the remainder of the open area. Low concentrations of faeces around edges were recorded with gravid females. The ratio of numbers of faeces in the shelter and those on the remainder of the arena was nearly identical in all tested groups. The rate of faeces deposition fluctuated during colonization of a new refuge. The role of faeces containing aggregation pheromone and ammonia in the ecology and behaviour of B. germanica is discussed.
Behavioral responses of lightbrown apple moth neonate larvae on diets containing Bacillus thuringiensis formulations or endotoxins
Authors: Harris M. O. , Mafile'o F. , Dhana S. 
Published: October 2003

AbstractBehavioral responses of individual lightbrown apple moth, Epiphyas postvittana (Walker), neonate larvae to Dipel or the Bacillus thuringiensis delta endotoxins CryIAc and CryIBa incorporated into artificial diets were measured in choice and no‐choice treatments. Frass production and the spinning of silken shelters were delayed when larvae were given diets containing Dipel or Bt endotoxins. In choice treatments larvae did not exhibit an initial preference for control diets over diets with Dipel or Bt endotoxins but accumulated on control diets over a period of days, apparently because larvae that first settled on Dipel or endotoxin diets abandoned diets while larvae that fed on control diets remained on diets throughout the experiment. Abandonment of diets containing Dipel or endotoxins was also apparent in no‐choice treatments. Larvae exposed to such diets were more likely to be observed walking or at different sites from one observation to the next, and produced frass and silken feeding shelters at multiple sites rather than a single site. The implications of these findings for the use of B. thuringiensis as a commercial spray or for the use of B. thuringiensis endotoxin genes as resistance factors to be expressed in transgenic apples are discussed.
Influence of plant structural complexity on the foraging success of Trichogramma minutum: a comparison of search on artificial and foliage models
Authors: Lukianchuk J. L. , Smith S. M. 
Published: October 2003

AbstractThe influence of structural complexity on the foraging success for host eggs (Ephestia kuehniella Zeller) by Trichogramma minutum Riley was investigated in the laboratory. Naive females were released into arenas with structurally different paper models or foliage (simple: trembling aspen Populus tremuloides Michx., complex: balsam fir Abies balsamea L.). Observations of individual females were made every 15 min and searching success was measured by the number of host egg clusters found and the amount of time taken to find them, within a period of 196 min. Females found significantly more egg clusters and were quicker at finding them on the sample paper and foliage surfaces than on the most complex paper or foliage surfaces. Older females (2–3 days) were more successful and searched quicker than younger (<24 h) females on all paper surfaces. The timed observations suggested that wasps which spent more time walking had a significantly decreased probability of finding an egg mass and were significantly slower at finding them. Females that spent more time on paper surfaces had an increased probability of finding an egg mass. The significance of searching differences is discussed in relation to the potential effects of plant surfaces on Trichogramma movements and to the physiological readiness of the wasp.
Toxicity of fipronil to German and American cockroaches
Authors: Kaakeh Walid , Reid Byron L. , Bennett Gary W. 
Published: October 2003

AbstractTopical and oral toxicity of fipronil, compared to chlorpyrifos, was determined for the German cockroach, Blattella germanica (L.), and American cockroach, Periplaneta americana (L.). Fipronil and Combat bait matrices were evaluated for their attractancies to both species. In the topical toxicity tests, LD50's of fipronil, at 72 h after topical application, were 0.03 and 0.02 μg/g for adult B. germanica and P. americana, respectively. Fipronil was significantly more toxic than topically applied chlorpyrifos (LD50's were 0.06 and 0.16 μg/g for B. germanica and P. americana, respectively). The oral toxicity of fipronil and chlorpyrifos in Petri dish experiments, against both species, was affected by stage (for B. germanica), diet concentration, and feeding assay. Fipronil caused higher mortality of B. germanica than chlorpyrifos in two feeding assays (continuous and abbreviated). Both compounds were equally toxic to adult males of P. americana at all rates. Fipronil caused higher nymphal mortality than chlorpyrifos 48–72 h after exposure in both feeding assays. In large population chamber tests, fipronil bait was more effective and faster in killing P. americana than Raid and Combat. LT50's were 0.8, 2.4, and 7.6 d for fipronil, Raid (a.i. = chlorpyrifos), and Combat (a.i. = hydramethylnon) baits, respectively. Mortality reached 96.5, 93.4, and 84.6%, respectively, at the end of the 14 d test. In the bait attractancy tests, both strains of B. germanica were attracted similarly to fipronil and Combat bait matrices. P. americana were attracted more to fipronil than to Combat bait matrix or to other alternative foods.