bluuebunny/crossref_metadata_2025_split huggingface dataset:
A four‐year investigation into the efficacy of domiciles for enhancement of bumble bee populations
Authors: Barron M. C. , Wratten S. D. , Donovan B. J. 
Published: March 2003

Abstract1 Eighty four‐unit domiciles for introduced bumble bees (Bombus spp.) were placed in 16 field margins at Lincoln, New Zealand in the 1995–96 southern summer. Fifty‐five were placed in the margins of intensively managed fields, with the remaining 25 being in less disturbed habitats, which had more spring/summer floral resources.2 The number of nests founded over the four‐year study period increased from one to 27. Bombus hortorum was a much more frequent colonist than was B. terrestris, with B. ruderatus colonizing only in the fourth year.3 In the ‘intensive’ sites, mean four‐year occupancy was only 2%, whereas in the less disturbed sites it was 13%.4 There was a positive association between bumble bee occupancy of the domicile compartments in the previous year and occupancy in the current year. No association was found between previous occupancy by mice and subsequent occupancy by bumble bees.5 The potential for adding Bombus nest sites to agricultural land to enhance local populations, and, potentially, pollination of seed crops, is discussed. Adding domiciles in intensively managed landscapes may not be very effective unless spring floral resources are enhanced as well.
Oviposition preference and larval survival of Diprion pini on Scots pine clones in relation to foliage characteristics
Authors: Pasquier‐Barre F. , Géri C. , Goussard F. , Auger‐Rozenberg M. A. , Grenier S. 
Published: March 2003

Summary1 When laying eggs, adult female Diprion pini discriminated between clones of Scots pine, Pinus sylvestris.2 Larval survival was affected by Scots pine clone but was not correlated with oviposition preference.3 Diprion pini laid most eggs on tougher needles of Scots pine.4 There was no evidence to suggest that D. pini is responding to the monoterpene composition of the foliage.
Biology, demography and community interactions of Tarsonemus (Acarina: Tarsonemidae) mites phoretic on Dendroctonus frontalis (Coleoptera: Scolytidae)
Authors: Lombardero María J. , Klepzig Kier D. , Moser John C. , Ayres Matthew P. 
Published: March 2003

Summary1 Dendroctonus frontalis, the southern pine beetle, is associated with a diverse community of fungi and mites that are phoretic on the adult beetles. Tarsonemus ips, T. kranzti and T. fusarii (Acarina: Tarsonemidae) may interact within this community in ways that link the population dynamics of D. frontalis, the mites and three dominant species of fungi. We explored species associations by comparing the dietary suitability of different fungi for Tarsonemus spp.2 All three mite species fed and reproduced at high rates when feeding on the bluestain fungus, Ophiostoma minus, which is an antagonist of D. frontalis larvae.3 Mites also had positive population growth rates when feeding upon Ceratocystiopsis ranaculosus, one of the mycangial fungi, but could barely reproduce when feeding upon Entomocorticium sp. A, the mycangial fungus that is most suitable for D. frontalis.4 During the time from colonization of a tree by D. frontalis adults until departure from the tree of their progeny (≈ 40 d at 30 °C), mite populations feeding upon O. minus can increase by factors of up to 209 (T. fusarii), 173 (T. ips) or 384 (T. krantzi). These high growth rates are allowed by rapid development (age of first reproduction = 8–9 d), high fecundity (≈ 1 egg/d) and high longevity (> 28 d).5 Precocious mating increases the chance that females are mated prior to colonizing a new tree and arrhenotokous parthenogenesis permits reproduction by unmated females.6 Tarsonemus mites may introduce negative feedback into D. frontalis population dynamics by generating indirect interactions between D. frontalis and O. minus.
Complex emergence patterns in a bark beetle predator
Authors: Reeve John D. 
Published: March 2003

Abstract1 The emergence pattern of Thanasimus dubius (F.) (Coleoptera: Cleridae), a common predator of the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Scolytidae), was studied under field conditions across different seasons. A simple statistical model was then developed to characterize the emergence data, using the truncated geometric distribution. Data are also presented on the mortality of T. dubius eggs at various temperatures and humidities in an effort to explain certain aspects of emergence behaviour.2 Emergence of T. dubius from a given tree usually occurred in several discrete episodes across a two‐year period, with most individuals emerging in spring or autumn. Almost no emergence occurred in July and August, which may be an adaptation to avoid high temperature mortality. Emergence patterns appeared similar across seasons, with the time of year serving mainly to shift the pattern through time.3 Cycles in D. frontalis abundance may be the result of delayed density dependence generated by its natural enemy complex. The predator T. dubius is likely to be an important component of this delayed density dependence, because of its lengthy development time and apparent impact on D. frontalis.
Larval performance in relation to oviposition site preference in olive kernel moth (Prays oleae Bern., Yponomeutidae, Praydina)
Authors: Petrakis Panos V. 
Published: March 2003

Abstract1 The tri‐voltine moth Prays oleae Bern. spends its larval stages on the native olive tree (Olea europaea L. var. sylvestris Brot. and five cultivars, Oleaceae) mining the leaves, the flowers and the fruits in each generation; it seldom switches to other native or introduced confamilial plant species.2 In this study the pattern of oviposition of the olive moth was examined in olive fields and natural vegetation, in relation to in situ recruitment as an outcome of processes such as density dependence or risk spreading.3 Larval body size (width of epicranial sclerites) was also examined and compared between host substrates, years and morphological, physiological, ecological and nutritional attributes of the host.4 The factors influencing the oviposition pattern of the olive moth such as the carbon/nitrogen ratio, number of flowers, branch length and previous leaf damage were ranked differently in different cultivars.5 ‘Hot spots’, i.e. olive trees or parts of trees receiving a high egg load, were found to be the result of in situ recruitment.6 Physiological mortality among first instar larvae was significantly negatively correlated with the number of oviposited upon leaves; suggesting that the adult selects for oviposition the best available substrate.7 As adult moths selected leaves with minimal probability of abscission for oviposition, leaf abscission was not a major mortality factor, although first instar larvae reduced leaf longevity.8 Host quality did not affect all larval stages in the same way.9 The more nutritionally poor the substrate, the longer the duration of the larval stage feeding on it. The phenological timing of the insect life stages very closely tracks the phenological phases of its host plant, primarily focusing on the most nutritious host stage in terms of larval performance.
Inter‐tree distribution of the spruce web‐spinning sawfly,Cephalcia abietis, at endemic density
Authors: Rodeghiero M. , Battisti A. 
Published: March 2003

Abstract1 The spatial distribution of forest defoliating insects at endemic density is a generally little known aspect of pest biology, which may have some importance in monitoring and prediction of outbreaks. In a natural spruce stand in Northern Italy it was possible to detect the presence of some species of web‐spinning sawflies (Cephalciaspp.) at endemic density. This was done over a 3‐year period by using trapping devices for both adults and larvae, including a trap which intercepted adult females climbing the trunk. Traps were operated on eight sample trees with signs of defoliation of the previous year (focal trees) and on 14 trees lacking signs of larval feeding (neighbour trees).2 Trunk traps on focal trees caught a higher number of adult females than traps on neighbour trees in each of the 3 years considered. The distribution pattern of catches was not spatially autocorrelated at any of the distance bands considered. Focal trees produced more mature larvae per adult female ofC. abietisthan neighbour trees, indicating that insect performance was higher on focal trees.3 The endemic population density ofC. abietiswas similar to that observed in other forests and the relationships between yellow trap catches and prepupal density fitted adequately with the predictive model validated forC. arvensis. The endemic density of the spruce web‐spinning sawflies seems to he higher than that of pine diprionids, and outbreak‐prone species ofCephalciaseem to be more abundant than non‐outbreak species even at very low population level.
Egg allocation by Bracon hylobii Ratz., the principal parasitoid of the large pine weevil (Hylobius abietis L.), and implications for host suppression
Authors: Henry C. J. , Day K. R. 
Published: March 2003

Summary1 The braconid parasitoid Bracon hylobii Ratz. is one of the few specialist natural enemies of the large pine weevil, Hylobius abietis L., a destructive pest of conifer transplants. An assessment of its role as an agent of biological control requires a detailed knowledge of the allocation of its reproductive effort.2 Parasitoid females were continuously observed in laboratory culture with individually reared host larvae in bark discs. The outcome of sequential parasitoid–host encounters was recorded by subsequent examination of hosts and by rearing all parasitoids.3 Parasitoids avoided ovipositing on host larvae < 100 mg fresh weight, even though such larvae represented sufficient biomass for complete parasitoid development. All larger larvae were vulnerable to attack, which leaves a window of vulnerability for parasitoids of about 90% of weevil larval life.4 Parasitoids presented with a range of host sizes showed no preference above 100 mg for the size of host first attacked, but allocated more eggs and a greater total handling time to larger hosts.5 Most eggs were deposited on the first host attacked, with progressively fewer allocated to subsequent hosts. However, oviposition experience did not affect the time spent on the next host.6 From these results it is anticipated that when weevil larval size is reduced by less favourable feeding substrates, fewer parasitoid eggs will be allocated to each but more host larvae will ultimately be attacked.7 Generation time, host finding, oviposition rate, clutch size, life expectancy and diapause induction are strongly affected by temperature. Life expectancy is substantially shorter for parasitoids deprived of non‐host food supplement. At 15 and 20 °C the number of hosts attacked and the number of eggs deposited decreased with female age.8 Bracon hylobii is inevitably poorly synchronized with a variable life‐cycle host; it is egg‐limited and can enter diapause at a relatively high field temperature. None of these characteristics suggest that it could stabilize the abundance of its host below an economically acceptable threshold density. However, the reproductive potential of the parasitoid suggests that it could make a significant contribution to larval mortality and suppress adult recruitment, thus complementing other control strategies.
Effect of hunger on yellow water trap catches of hoverfly (Diptera: Syrphidae) adults
Authors: Hickman Janice M. , Wratten Stephen D. , Jepson Paul C. , Frampton Chris M. 
Published: March 2003

Summary1 An experiment was conducted in a winter wheat field using yellow water traps at crop height and at ground level, near to and distant from flowers, to test the hypothesis that such traps are seen as a source of food by flower‐feeding adult hoverflies and are therefore likely to selectively trap hungry individuals. Hoverflies caught in each trap were counted and identified and the amount of pollen in their guts was assessed. Ratios of numbers of hoverflies seen in the wheat crop to numbers caught in nearby traps were compared for the different treatments.2 Most hoverflies were caught in crop‐high traps but they included a high proportion of individuals with empty guts. The taxa were: Episyrphus balteatus (De Geer), Metasyrphus corollae (F.) (these species together accounted for over 90% of the individuals trapped), with Sphaerophoria spp., Syrphus spp., Scaeva pyrastri (L.), Melanostomini and unidentified others making up the rest.3 Significantly fewer hoverflies were captured in low than in high traps. The ratios of numbers trapped to numbers observed, in flower and in no flower treatments would be expected to be the same if the traps were not selective. This was supported for low traps. With high traps, however, there was a highly significant difference between the ratios (71.34 and 126 : 8, respectively).4 Flies captured in high traps had less pollen in their gut than those captured in low ones. At each distance, more E. balteatus captured in high traps were in pollen category 1 (< 20 grains) than in any other category. The opposite state was seen in low trap catches, where most flies were in category 5 (> 5000 grains). Median pollen categories were 2 (21–200 grains) and 4 (1501–5000 grains) for flies caught in high and low traps, respectively.5 The ecological selectivity of traps according to their height and the physiological condition of the targeted individuals is a problem likely to affect many trapping systems apart from the one described in this paper.
Preliminary experiments on the olfactory responses of Pterostichus melanarius Illiger (Coleoptera: Carabidae) to intact plants
Authors: Tréfás H. , Canning H. , McKinlay R. G. , Armstrong G. , Bujáki G. 
Published: March 2003

Summary1 In two successive years, the olfactory responses of Pterostichus melanarius Illiger (Coleoptera: Carabidae) to intact cabbage and white clover plants were studied, using a four‐arm olfactometer.2 The first set of experiments tested the response to the odours of cabbage, white clover and the two plants grown together against potting compost; in the second and third sets of experiments, white clover and cabbage were tested, respectively.3 The results indicate that female P. melanarius individuals are arrested by the combined odours of cabbage and white clover, spending significantly more time in the cabbage with white clover odour field than in either the cabbage, white clover or control odour fields.4 Similar results were not found for males.5 Cabbage plants alone did not elicit significant responses in either sex.6 White clover alone did not elicit significant responses by females and the responses of males were not uniform in the two successive years.
The biology and management of wireworms (Agriotes spp.) on potato with particular reference to the U.K.
Authors: Parker William E. , Howard Julia J. 
Published: March 2003

Summary1 This paper reviews and interprets relevant work on the biology and management of wireworms (Agriotes spp.) within the context of potato production in Europe, with particular reference to the U.K. Although the review concentrates on Agriotes spp., the extensive world literature on other Elateridae of economic importance is also drawn upon.2 Possible reasons for the apparent increase in the importance of wireworms on the potato crop are discussed, followed by a review of wireworm biology, risk assessment techniques (soil sampling, bait trapping and adult pheromone trapping), crop damage, and cultural, biological and chemical control methods.3 It is clear that the process of site risk assessment followed by appropriate control measures (usually insecticide use) will remain the mainstay of wireworm management programmes. However, there is considerable scope for adopting new risk assessment techniques, such as pheromone trapping of adult beetles.4 These control measures will need to be underpinned by a greater understanding of wireworm biology, particularly adult dispersal. Factors affecting the initiation and maintenance of wireworm populations in individual fields also require further study. The current use of insecticides could also be optimized by a better appreciation of the interactions between insecticide use, potato variety choice and harvest dates.
Population abundance and movement of Frankliniella species and Orius insidiosus in field pepper
Authors: Ramachandran Suresh , Funderburk Joe , Stavisky Julie , Olson Steve 
Published: March 2003

Summary1 A recent study revealed the capacity of the Orius insidiosus to suppress populations of Frankliniella spp. in field pepper during the spring when thrips are rapidly colonizing and reproducing. In this study, population abundance in pepper during spring, summer, and autumn was determined to understand better predator/prey dynamics under local conditions. Local movement between pepper flowers also was quantified to examine how population attributes of the predator allow suppression of rapidly moving populations of prey.2 Randomized complete block experiments established in the autumn of 1998 and the spring of 1999 included treatments of biological and synthetic insecticides, which altered the population densities of predator and prey. Numbers of O. insidiosus in relation to prey were sufficient in 1998 to prevent build‐up of thrips populations. In 1999, populations of thrips were unable to recover from near extinction owing to persistence of the predator. The predator rapidly recolonized plots treated with insecticide.3 Greenhouse plants of the same age as field plants were used to monitor movement by predators and prey. Movement by F. occidentalis was limited, whereas F. tritici and F. bispinosa moved rapidly to the greenhouse plants. The males of each thrips species moved more rapidly than the females. There was evidence that rapid movement assisted F. tritici and F. bispinosa in avoiding predation, but O. insidiosus also moved very rapidly to the greenhouse plants. This attribute explains the predator's ability to suppress thrips rapidly even when populations are rapidly colonizing and reproducing in the flowers.
Within‐tree and seasonal distribution of the pine woolly aphidPineus boernerionPinus kesiyatrees
Authors: Chilima C. Z. , Leather S. R. 
Published: March 2003

Summary1 The spatial and temporal distribution of pine woolly aphids,Pineus boerneri(Homoptera: Adelgidae) a pest of exotic pine trees in Malawi, was investigated in 5‐year‐oldPinus kesiyatrees.2 Pineus boerneriwas generally found to settle and reproduce on the outer shoot‐end sections of youngP. kesiyatrees. There was no evidence of preference for any particular levels of the tree canopy.3 The study suggests that the biological performance and, by implication, the pest status ofP. boerneriin youngP. kesiyatrees can be influenced by external factors, particularly by the within‐tree and seasonal fluctuations in the level of nitrogen in the host trees, total rainfall and canopy structure.4 These findings are discussed in relation to possible management and control ofP. boerneriin Malawi.
Effects of host plant species on the interaction between the parasitic wasp Diospilus capito and pollen beetles (Meligethes spp.)
Authors: Billqvist Andreas , Ekbom Barbara 
Published: March 2003

Summary1 Field studies were conducted in central Sweden to establish whether two host plants with high and low suitability for pollen beetles (Meligethes aeneus Fabr. [Coleoptera: Nitidulidae] and Meligethes viridescens Fabr.) affected the parasitoid Diospilus capito Nees [Hymenoptera: Braconidae].2 Samples of larvae were taken from fields with plots of white mustard, Sinapis alba L. and spring rape, Brassica napus L. in 1997 and 1998. Levels of parasitism and the survival and size of D. capito were measured to determine any influence of the host plant species. Survival and weights of pollen beetles from S. alba and B. napus were also measured.3 Levels of parasitism between 8% and 29% were recorded. There was a significantly higher likelihood of being parasitized by D. capito for beetle larvae developing on S. alba than on B. napus. We argue that semiochemical or morphological properties of plant species could be responsible for differential parasitism by D. capito.4 Neither survival of D. capito nor parasitoid size differed from hosts developing on S. alba or B. napus. Pollen beetle emergence was the same for both plant species, but beetles that developed on S. alba weighed less than those from B. napus. Results suggest that the partial resistance of S. alba to the pollen beetle will have no negative effects on the parasitoid D. capito.
Effect of plant patch shape on the distribution and abundance of three lepidopteran species associated with Brassica oleracea
Authors: Muriel Sandra B. , Grez Audrey A. 
Published: March 2003

Abstract

Plant patch shape may affect the abundance of herbivorous insects. Patches of the same size but longer or irregular have a higher perimeter/area relationship (P/A) than square or regular ones, which may determine the immigration, emigration and abundance of individuals in the patch.
Only specialist species should be affected by plant patch shape. Those species that are more abundant in smaller patches should be more abundant in patches with higher P/A, whereas those that are more abundant in larger patches should be more abundant in patches with lower P/A.
We studied the density of eggs, larvae and pupae of Pieris brassicae, Plutella xylostella and Trichoplusia ni in square (low P/A) and I‐shaped (high P/A) patches of 144 plants of Brassica oleracea. We also estimated their immigration to these patches, and the final plant weight.
Plant patch shape affected the abundance, but not the distribution, of the two specialist species. Whereas P. brassicae was denser in I‐shaped patches, P. xylostella was more abundant in square patches. The generalist T. ni was not affected by patch shape. Immigration of P. brassicae was higher in I‐shaped patches, but immigration of P. xylostella and T. ni was not affected by patch shape. Plants were heavier in the centre of square patches.
Our results suggest that plant patch shape affects the density of herbivorous insects and should be considered independently from other plant patch variables when studying the population dynamics of these organisms.
Soybean seed damage by different species of stink bugs
Authors: Corrêa‐Ferreira Beatriz S. , De Azevedo Joacir 
Published: March 2003

Abstract

Damage caused by the three main species of stink bugs occurring on soybean Nezara viridula (Linnaeus), Piezodorus guildinii (Westwood) and Euschistus heros (Fabricius) was compared in field cages and in greenhouses. Infestation levels of 4 stink bugs/m row of plants (field cages) and 2 stink bug/plant (greenhouse) for 15 days during the pod filling stage are reported. At harvest, the yield and seed quality were evaluated.
In the field, there was no difference in yield between infested and insect‐free plants, but damage to seed quality varied with stink bug species. Plants damaged by P. guildinii had the lowest quality seeds. From 50 g seed samples harvested in the field, the mean weight of seeds classified as ‘good’ was 37.3 g in plants infested with P. guildinii, compared to 41.8, 44.2 and 46.6 g in plants infested with E. heros, N. viridula and the control, respectively.
Plants infested with P. guildinii showed the highest number of seeds damaged by stink bugs, whereas those infested with E. heros showed the lowest damage.
Plants infested with P. guildinii had 18.5% damaged seeds, higher than the 3.6% and 3.4% damaged seeds from plants infested with the two other species and 0.1% in control plants. The percentage of non‐viable seeds due to stink bug damage was 5.7% for P. guildinii but lower for the other two species.