bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase‐retrieved pupil functions in wide‐field fluorescence microscopy
Authors: HANSER B. M. , GUSTAFSSON M. G. L. , AGARD D. A. , SEDAT J. W. 
Published: September 2004

SummaryPupil functions are compact and modifiable descriptions of the three‐dimensional (3D) imaging properties of wide‐field optical systems. The pupil function of a microscope can be computationally estimated from the measured point spread function (PSF) using phase retrieval algorithms. The compaction of a 3D PSF into a 2D pupil function suppresses artefacts and measurement noise without resorting to rotational averaging. We show here that such ‘phase‐retrieved’ pupil functions can reproduce features in the optical path, both near the sample and in the microscope. Unlike the PSF, the pupil function can be easily modified to include known aberrations, such as those induced by index‐mismatched mounting media, simply by multiplying the pupil function by a calculated aberration function. PSFs calculated from such a modified pupil function closely match the corresponding measured PSFs collected under the aberrated imaging conditions. When used for image deconvolution of simulated objects, these phase‐retrieved, calculated PSFs perform similarly to directly measured PSFs.
A Late Mesolithic Hunting Station at Agernæs, Fyn, Denmark
Authors: Richter Jane , Noe-Nygaard Nanna 
Published: September 2004

The Late Ertebølle hunting site from Agernæs, Fyn/Funen, Denmark, around 4200 cal yrs BC (51–5600 14C yr BP), has yielded a total of 32 animal species. They include eight species of fur animals comprising pine marten, polecat, wolf, fox, domestic dog, lynx, wild cat and otter. Neonatal red deer and roe deer were apparently only hunted for their skins. Animals hunted for consumption comprise aurochs, wild boar, adult red deer and roe deer. The season of activity is determined by the presence of newborn red deer, roe deer, piglets of wild boar and the time of skinning of the pine marten. The biometrical data from red deer, roe deer and wild boar indicate free migration between the island of Fyn and the mainland, Jylland/Jutland.
The inhabitants of the site seem to have been highly focused on the hunting of fur animals. Pine marten has been a major target with 33 individuals. Specialized hunting strategies have further been applied. Bones from 10 species indicate that the main animal food source was terrestrial, while the isotope data from man and dog indicate a dominant marine diet. It is thus likely that Agernæs was a hunting station, and represents a specialized site, indicating that economic differentiation already was in progress. The termination of the Late Atlantic climatic optimum (8000–5000 14C BP), radical changes of the forested landscape during the elm decline, and diversification of economic activities may have created the foundation for the introduction of domestic animals only a few hundred years later than the habitation of the Agernæs site. The main habitation period of the site appears to fall between the Late Atlantic and the Subboreal Littorina transgression by comparison with data from the Littorina-transgressions of Sjælland/Zealand at Vedbæk, Storebælt, Trundholm Mose, Troldestuen, and Tengslemark.
Interactions between a hunting spider and a web‐builder: consequences of intraguild predation and cannibalism for prey suppression
Authors: Denno Robert F. , Mitter Margaret S. , Langellotto Gail A. , Gratton Claudio , Finke Deborah L. 
Published: September 2004

Abstract. 1. Antagonistic interactions among invertebrate predators such as intraguild predation and cannibalism have the potential to dampen top‐down impacts on shared prey at lower trophic levels. Two abundant spider predators, the large wolf spiderPardosa littoralisand the small sheet‐web builderGrammonota trivitattaco‐occur on the salt marshes of eastern North America where they both attack planthoppers (Prokelisiaspp.), the dominant herbivores on the marsh. Experiments both in the laboratory and field were used to assess the incidence of intraguild predation and cannibalism in these spiders and elucidate how such antagonistic interactions influence planthopper suppression.2. Functional response experiments showed that with an increase in planthopper prey density,Grammonotacaptured more prey but not a higher proportion of that offered.Pardosaexhibited the same response whenGrammonotawere offered as intraguild prey. Both functional responses were type I over the range of prey densities offered.3. Grammonotais moderately cannibalistic, and the presence of planthopper prey reduced the incidence of cannibalism.4. Factorial experiments in the laboratory showed thatPardosabut notGrammonotareduced planthopper prey populations when prey density was low. By contrast, at high prey densities, bothPardosaandGrammonotahad significant adverse effects on planthopper populations. Moreover, there was an interactive effect such thatGrammonotareduced planthopper populations relatively more whenPardosawas absent than when it was present.5. There was direct evidence for the intraguild predation ofGrammonotabyPardosasuch that fewerGrammonotasurvived in the presence ofPardosathan when it was absent. This result occurred whether planthopper prey were abundant or not.6. Field releases ofGrammonotain open plots resulted in significant but small decreases in the density of planthopper prey, both nymphs and adults.7. Enhancing densities ofPardosain open plots resulted inGrammonotasuppression. The intraguild predation ofGrammonotaat this enhancedPardosadensity, however, did not precludePardosafrom significantly reducing planthopper populations.8. Although there was evidence thatGrammonotareduced planthopper populations and that the intraguild predation ofGrammonotabyPardosaoccurred, the strength of these interactions was relatively weak given the low consumption rate of planthoppers byGrammonota(< 3 day–1) andGrammonotabyPardosa(≈ 2 day−1). Thus, weak asymmetric intraguild predation among spiders on the marsh likely dampens but does not eliminate the ability ofPardosato exert significant top‐down control on planthopper populations.
Population dynamics and occurrence of Spodoptera frugiperda host strains in southern Florida
Authors: Meagher Robert L. , Nagoshi Rod N. 
Published: September 2004

Abstract.  1. The development of an area‐wide management programme for the migratory pest fall armyworm [Spodoptera frugiperda (J. E. Smith)] requires knowledge of its preferred habitats throughout the year and a detailed description of seasonal changes in population numbers.2. Molecular markers were used to determine the host strain (corn or rice) of male moths captured in sex pheromone‐baited traps placed in different habitats in the overwintering areas of southern Florida.3. The results indicated that rice strain moths were found in all traps and that this strain was the primary population observed in naturalised pasture and wetlands in southern Florida. In comparison, larger populations of both strains and a higher proportion of corn strain moths were observed in areas associated with golf courses, agriculture, or urban development. Corn strain adults were most prevalent during the spring and early summer.4. These results represent the first geographical survey of fall armyworm host strain distribution in Florida and indicate that corn strain moths are limited in their habitat choice while rice strain moths have a substantially broader range. The localisation of the corn strain population to discrete areas at specific times of the year provides an opportunity to reduce or delay its northward migration.
Population responses of a conifer‐dwelling aphid to seasonal changes in its host
Authors: Day Keith R. , Armour Hazel , Docherty M. 
Published: September 2004

Abstract.  1. Current evidence suggests that seasonal changes in spruce needle sap nutrients have a decisive influence on green spruce aphid (Elatobium abietinum) population density, but the mechanisms of population change, the roles of development rate, fertility and mortality, and the existence of density‐dependent processes, are not clearly understood.2. Experimental studies of aphid populations were conducted in controlled environments to estimate seasonal patterns in aphid mean relative growth rate, prenatal development, fertility, and mortality. Studies were also made of the effect of aphid crowding on vital rates.3. Independent of the degree of aphid crowding, seasonal changes in the amino acid concentration of needle sap were tracked by aphid growth rate, fertility (and adult size), but not by rates of aphid mortality. The most pronounced change in vital rates, and the one most likely to drive seasonal population change, was in fertility. Prenatal development time actually became shorter in periods when nutrients were scarce, but the resulting adult aphids were smaller and less fertile than during periods of improved nutrition.4. Density dependence of vital rates was only observed during mid‐summer when nutrients were least available. Mortality, growth rate, and prenatal development were the most strongly density‐dependent processes. In contrast, there was no evidence that fertility rates were likely to respond to crowding.5. There were no important differences between populations reared on small, potted spruce trees and those on plantation trees aged 25 years. This gives confidence that demographic data from a variety of field and laboratory sources could be used to compile data appropriate for population models.
The importance of specialist natural enemies for Chrysomela lapponica in pioneering a new host plant
Authors: Gross Jürgen , Fatouros Nina E. , Neuvonen Seppo , Hilker Monika 
Published: September 2004

Abstract.  1. The Salicaceae have been suggested as ancestral host plants of Chrysomela species (Coleoptera: Chrysomelidae). In Chrysomela lapponica, some populations are specialised on salicaceous plants, but others have switched to birch. This study aimed to elucidate the significance of natural enemies as possible selective forces for the host plant shift of C. lapponica from willow to birch.2. Two C. lapponica populations were studied, one specialised on willow Salix borealis in Finland, and another one specialised on birch Betula pubescens in the Czech Republic. Abundances of predators and parasitoids on birches and willows were recorded at both population sites. Furthermore, field and laboratory experiments were conducted.3. Field data do not support the hypothesis that generalist predators affected the host shift from willow to birch in C. lapponica.4. Parasitism of C. lapponica (pre)pupae by a specialised phorid fly was significantly stronger in specimens living on willow than in birch‐living ones.5. The predatory syrphid Parasyrphus nigritarsis specialised on Chrysomelinae was only detected on willows. The syrphid preferred to orient towards substrates treated with defensive larval secretion or faeces of the willow‐specialised C. lapponica specimens compared with the birch‐specialised ones.6. The data suggest that specialised parasitoids and predators might have been driving forces for C. lapponica to leave willows and to pioneer birches as sites with a lowered risk of predation and parasitism. This hypothesis is discussed with respect to results of earlier studies on the impact of bottom‐up effects by the plant.
Age and experience influence patch assessment for oviposition by an insect predator
Authors: Frechette Bruno , Dixon Anthony F. G. , Alauzet Claude , Hemptinne Jean‐Louis 
Published: September 2004

Abstract.  1. Dynamic models of optimal foraging predict that an animal's decision to accept or reject a patch depends not only on the environment and patch quality, but also on its internal state. Previous experiments have shown that the two‐spot ladybird beetle, Adalia bipunctata (L.), is reluctant to lay eggs in a patch of prey contaminated by the oviposition‐deterring pheromone produced by conspecific larvae.2. An experiment was conducted to test whether the internal state of an A. bipunctata female affects its oviposition response to oviposition‐deterring pheromone. Firstly, the oviposition response to oviposition‐deterring pheromone of young and old females was compared. Secondly, the oviposition response to oviposition‐deterring pheromone of females previously exposed continuously to oviposition‐deterring pheromone was compared with that of females of the same age but with no previous experience of oviposition‐deterring pheromone.3. Old females and females with previous experience of oviposition‐deterring pheromone were less reluctant to lay eggs in the presence of oviposition‐deterring pheromone than young and naive females. These results are consistent with the predictions of optimal foraging theory.
Intra‐ and interspecific aggregation of north temperate dung beetles on standardised and natural dung pads: the influence of spatial scale
Authors: Hutton Stephen A. , Giller Paul S. 
Published: September 2004

Abstract.  1. The spatial distribution of north temperate dung beetles (Aphodius, Sphaeridium, and Margarinotus) was investigated at three spatial scales (scale a between all pads – large spatial scale, small patch size; scale b between block – large spatial scale, large patch size; scale c within block – small spatial scale, small patch size) in the field using standardised and naturally dropped dung pads that varied in size and volume.2. Results indicated that all the major colonising species of dung beetle expressed strong intraspecific aggregation, while interspecific aggregation, though present, was of a lesser magnitude.3. In both controlled and natural dung treatments, intra‐ and interspecific aggregation decreased with increasing patch size (from pad to block) and also decreased with decreasing spatial scale (from whole plot to within‐block scale).4. The data also suggested that intraspecific aggregation was more important than interspecific aggregation in the distribution of adult dung beetles in natural and standardised dung pads and hence has the potential to facilitate coexistence.5. Intra‐ and interspecific aggregation was greater in the natural dung compared with that of the standardised dung, and the effect of pad size partly explains this phenomenon.6. The within‐patch spatial distribution of dung beetles observed in the natural and standardised dung was possibly mediated through within‐patch differences between the two treatments. Six confounding factors could explain this difference and these factors are discussed in relation to resource utilisation by north temperate dung beetles.
Intraspecific variation in the strength of density dependence in aphid populations
Authors: Agrawal Anurag A. , Underwood Nora , Stinchcombe John R. 
Published: September 2004

Abstract.  1. Experimental evidence is presented for positive, negative, and no density dependence from 32 independent density manipulations of milkweed aphids (Aphis nerii) in laboratory and field experiments. This substantial variation in intraspecific density dependence is associated with temperature and host‐plant species.2. It is reported that as population growth rate increases, density dependence becomes more strongly negative, suggesting that the monotonic definition of density dependence used in many common population models is appropriate for these aphids, and that population growth rate and carrying capacity are not directly proportional.3. For populations that conform to these assumptions, population growth rate may be widely applicable as a predictor of the strength of density dependence.
Phorid fly parasitoids of invasive fire ants indirectly improve the competitive ability of a native ant
Authors: Mehdiabadi Natasha J. , Kawazoe Elizabeth A. , Gilbert Lawrence E. 
Published: September 2004

Abstract.  1. The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is an invasive species of south‐eastern U.S.A. Since its introduction from South America approximately 70 years ago, this pest has devastated natural biodiversity.2. Due to such ecological costs, Pseudacteon phorid fly parasitoids (Diptera: Phoridae) from South America are being introduced into the U.S.A. as a potential biological control agent. Here, the indirect effects of these specialised parasitoids on an interspecific native ant competitor, Forelius mccooki (Hymenoptera: Formicidae), are evaluated.3. Over the course of a 50‐day laboratory experiment, the results show that the native ant improved aspects of exploitative, but not interference, competition when S. invicta‐attacking flies were present compared with when they were absent.4. Forelius mccooki colonies from the phorid treatment had approximately twice as many foragers at food baits relative to controls; however, there was no significant difference in interference aspects of competition or native ant colony growth between the two treatments.5. These results suggest that the S. invicta‐specialised parasitoids help shift the competitive balance more in favour of F. mccooki than if these flies were not present; however, this competitive advantage does not translate into increased colony growth after 50 days. These laboratory findings are interpreted with regard to the more complex interactions in the field.
Species diversity and structure of phytophagous beetle assemblages along a latitudinal gradient: predicting the potential impacts of climate change
Authors: Andrew Nigel R. , Hughes Lesley 
Published: September 2004

Abstract.  1. Assemblages of phytophagous beetles on Acacia were examined along a 1150 km latitudinal gradient in eastern Australia to investigate the potential effects of climate change on insect communities. The latitudinal gradient was used as a surrogate for differences in temperature. Several possible confounding variables were held constant by selecting comparable sites and emphasising a single host‐plant species.2. Total species richness increased towards the tropics, but there were no significant differences among latitudes for average species density, species richness, Fisher's α, or average Chao‐1 index.3. Beetles sampled along the gradient were classified into four climate change response groups, depending on their latitudinal range and apparent host specificity: cosmopolitan species, generalist feeders, climate generalists, and specialists. These four groups might respond differently to shifting climate zones. Cosmopolitan species (22% of community, found at more than one latitude and on more than one host plant) may be resilient to climate change. Generalist feeders (16%, found only at one latitude but found on more than one Acacia species) may well feed on several species but will have to move with their climatic envelope. Climate generalists (6%, found only on Acacia falcata but found at more than one latitude) may be constrained by the host species' ability to either cope with the changing climate or move with it. Finally, specialists (55%, found only on A. falcata and at only one latitude) may be forced to move poleward concurrently with their host species, or go extinct.4. The analyses indicate that community structure may be fairly resilient to temperature change. The displacement or local extinction of species, especially the species that are found at only one latitude and on only one host plant, however, may lead to significant changes in community composition.
Winged leaf‐cutting ants on nuptial flights used as transport by Attacobius spiders for dispersal
Authors: Ichinose K. , Rinaldi I. , Forti L. C. 
Published: September 2004

Abstract.  1. Sexuals of a leaf‐cutting ant, Atta bisphaerica Forel, left their nest for nuptial flights in October to December.2. When leaving a nest, 53 of the 479 winged sexuals (or alates) observed (11.1%) carried up to three inquiline spiders of Attacobius luederwaldti.3. Spiders exclusively selected winged sexuals, not workers, and preferred females, indicating their expectation of the stronger flight ability of females. Neither these sexuals nor workers that appeared out of the nest on flight days attempted to remove or attack spiders on the body of alates.4. New qucens landing from their nuptial flight did not carry spiders, indicating that the spiders had left the ants in the sky to be dispersed by wind.5. No spiders were found in more than 100 incipient nests, which were estimated to be 2–3 months old. This suggests that the spiders jumped off the alate during mid‐flight and dispersed on the wind to inhabit larger nests.
Shifting average body size during regeneration after pollution – a case study using ground beetle assemblages
Authors: Braun Sascha D. , Jones T. Hefin , Perner Jörg 
Published: September 2004

Abstract. 1. Pitfall data, collected periodically between 1980 and 1996, were used to analyse the spatial and temporal body size pattern of ground beetle assemblages (Carabidae) in a former polluted grassland.2. Two hypotheses were tested: (i) Siemannet al.'sefficiency–specialisation hypothesisthat predicts that during succession (or regeneration) processes the mean body sizes of consumer assemblages decrease and (ii) Blakeet al.'s hypothesis that predicts that smaller body sizes are found with increasing level of disturbance.3. Biovolume was considered as a determinant of ground beetle body size. This was analysed by using a digital–optical volume measurement. The mean error associated with the idealisation of the ground beetle body shape as an ellipsoid was determined as 10.24 ± 2.5%.4. A significant decrease in average ground beetle body size was recorded in moving from the pollution (1980) to the post‐pollution (1996) period. The mechanisms linked with ecological succession after factory closure (1990) were discussed as the main causal factor sustaining Siemannet al.'s hypothesis.5. The analyses of the mean body size during the transition period from the pollution to the post‐pollution period demonstrate that Blakeet al.'s hypothesis was also partly supported, and may overlay the effects driven by succession.6. It is therefore concluded that both hypotheses may be used to explain not only the change in body size from a highly polluted to a less polluted area, but also the relationship between habitat structure and predatory ground beetles.
Alcohol and pancreatitis mortality at the population level: experiences from 14 western countries
Authors: Ramstedt Mats 
Published: September 2004

ABSTRACTAims  To test if there is relationship between alcohol consumption and pancreatitis mortality at the population level.Data and methods  Annual pancreatitis death rates for 1950–95 were converted into age‐adjusted mortality rates per 100 000 inhabitants. Per capita alcohol consumption was measured by alcohol sales. The relationship was estimated with time‐series analysis on data from 14 western countries. Several models were tested with different assumptions about risk function and lag structure.Results  According to the assumed most appropriate model, a positive relationship was found in each country, and statistical significance was reached in all countries except from Finland, Italy and Canada. The magnitude of the association was fairly consistent across countries, with the alcohol effect parameters ranging between 0.05 and 0.14. However, Sweden and Norway deviated from this pattern with estimates between 0.30 and 0.40.Conclusions  Pancreatitis joins a wide range of causes of death where the mortality rate is influenced by per capita alcohol consumption, and more so in northern Europe. It is suggested that pancreatitis mortality is an important indicator of alcohol‐related harm, not least because a large amount of morbidity is likely to be connected to the mortality rate.