bluuebunny/crossref_metadata_2025 huggingface dataset:
Haemodynamic limitations and exercise performance in peripheral arterial disease
Authors: Green S.
Published: March 2003

It has been frequently argued that haemodynamic limitations are poor predictors of exercise performance in people with peripheral arterial disease (PAD) and intermittent claudication. This review has tried to address this argument through a review of published data that appears to support or counterbalance it, brief consideration of some of the methodological limitations associated with these data, as well as some other considerations. The main argument rests primarily upon data about the resting ankle–brachial index (ABI) and/or blood flow after calf exercise or an ischaemic challenge; whereas the counter argument rests mainly on data about blood flow during walking or cycling exercise. Consideration of the limitations of all methods suggests that the measurement of blood flow during exercise has the greatest value in explaining differences in exercise performance amongst claudicants; whereas the other methods are relatively limited in their explanatory value. This strengthens the counter argument and undermines the main argument proposed by others. Consequently, asserting that haemodynamic limitations are poor predictors of exercise performance in claudicants is not justified in light of available evidence.
Effects of exercise training on aerobic and functional capacity of end‐stage renal disease patients
Authors: Koufaki Pelagia , Mercer Thomas H. , Naish Patrick F.
Published: March 2003

The aim was to assess the effects of exercise training on aerobic and functional capacity of patients with end‐stage renal disease (ESRD). Patients completed an incremental exercise test on a cycle ergometer to determine VO2 peak and VO2 at ventilatory threshold (VT; V‐slope). On a separate day they performed two constant load exercise tests on a cycle ergometer at 90% of VT and at a workload of 33 W, to determine VO2 kinetics. Functional capacity was assessed using measurements of sit‐to‐stands (STS‐5, STS‐60) and a walk test. Dialysis patients were randomly allocated to an exercise (ET: n=18, age=57·3 years) or control (C: n=15, age=50·5 years) group. The ET group participated in an exercise training programme involving cycling for 3 months. Repeated measures ANOVA revealed significant time by group interactions (P < 0·05) following training for VO2 peak (ET: 17 ± 6·1 versus 19·9 ± 6·3, C: 19·5 ± 4·7 versus 18·8 ± 4·9 ml kg min–1) and VO2–VT (ET: 10·7 ± 3·5 versus 11·8 ± 3·3, C:12·9 ± 3·2 versus 11·9 ± 3·5 ml kg min–1). VO2 kinetics remained unchanged in both groups at 90% ‐VT, but a trend (P=0·059) towards faster kinetics at the 33 W was observed (ET: 49·6 ± 19·5 versus 37·8 ± 12·7, C: 42·8 ± 13 versus 49·4 ± 20·2 s). Significant time by group interactions (P < 0·05) were also observed for STS‐5 (ET: 14·7 ± 6·2 versus 11·0 ± 3·3, C: 12·8 ± 4·4 versus 12·7 ± 4·8 s) and STS‐60 measurements (ET: 21·2 ± 7·2 versus 26·9 ± 6·2, C: 23·7 ± 6·8 versus 24·1 ± 7·2). Three months of exercise rehabilitation significantly improves peak exercise capacity of patients with ESRD. Measurements of VO2 kinetics and functional capacity suggest that longer time might be needed to induce peripheral adaptations.
Behaviour of vaginal epithelial maturation and sex hormone binding globulin in post‐menopausal breast cancer patients during the first year of tamoxifen therapy
Authors: BERTOLISSI  , CARTEI  , TURRIN  , CIOSCHI  , RIZZI
Published: March 2003

bertolissi a., cartei g., turrin d., cioschi b. and rizzi v. (1998) Cytopathology9, 263–270

Behaviour of vaginal epithelial maturation and sex hormone binding globulin in post‐menopausal breast cancer patients during the first year of tamoxifen therapy

To evaluate the effect of tamoxifen on vaginal epithelial maturation and on oestrogen‐related hepatic synthesis, we prospectively studied the karyopyknotic index (KPI), the maturation index (MI), expressed as a percentage of parabasal (MI‐1), intermediate (MI‐2) and superficial (MI‐3) cells, as well as the serum levels of the oestrogen‐dependent sex hormone binding globulin (SHBG). Tests were performed at baseline, after 1, 3, 6 and 12 months of therapy in 64 post‐menopausal breast cancer patients. Basal KPI ranged from 0 to 9 (mean 1.5 ± 0.3) and rose 13.5‐fold to 21 ± 2.5 (P = 0.000) after the first 30 days of tamoxifen. Absence of KPI rise was observed in 23% of patients. Pretreatment MI figures 1, 2 and 3 were 56.9 ± 5.6, 41.7 ± 5.4 and 1.4 ± 0.3, respectively, and sharply shifted to the right (P = 0.000) after 1 month of therapy, indicating an increase of vaginal epithelial maturation. At baselines the SHBG mean value was 62.1 ± 3.3 nmol/l and underwent an increase of 44% (P = 0.000) after 30 days of tamoxifen. All of these observed 1‐month modifications remained stable up to the studied 12 months of therapy. Present findings indicate an early and persistent oestrogenic effect of tamoxifen on the vaginal epithelium and the hepatic synthesis of SHBG.
Value of radiologically guided fine needle aspiration cytology (FNAC) in the diagnosis of spinal tuberculosis: a study of 29 cases
Authors: Francis I. M. , Das D. K. , Luthra U. K. , Sheikh Z. , Sheikh M. , Bashir M.
Published: March 2003

Value of radiologically guided fine needle aspiration cytology (FNAC) in the diagnosis of spinal tuberculosis: a study of 29 cases

FNAC is a simple diagnostic tool for the initial evaluation of various deep seated pathological lesions. This study describes the applicability and practical aspects of the technique in establishing the diagnosis of spinal tuberculosis (TB) with the aid of radiographic guidance. The study was conducted in a major teaching hospital in Kuwait between the years 1985 and 1994. Twenty‐nine patients (M:F = 18:11 and age range 8–72 years) with clinically and/or radiologically suspected spinal TB were seen in the Department of Cytology, Mubarak Al Kabeer Hospital. The patients were re‐examined by either computed tomography (CT) scanning (n = 19) or fluoroscopy (n = 10) to localize the lesion for FNAC. FNAC smears were routinely stained with Papanicolaou and Diff Quik stains and one smear of each case was stained with Ziehl–Neelsen (Z‐N) stain for acid‐fast bacilli (AFB). Aspirated purulent material or syringe washings of dry aspirates were also submitted for microbiological cultures including AFB. Radiological and cytological findings were recorded in each case. Radiological findings included: bony rarefaction and destruction (93.1%), narrowed disc space (89.7%), soft tissue calcification (65.5%) and para‐vertebral abscess formation (51.7%). Cytological findings included: epithelioid cell granulomas (89.7%), granular necrotic background (82.8%) and lymphocytic infiltration (75.9%). Smears were positive for AFB in 51.7% of cases. A positive AFB culture was obtained in 82.8% of cases, including all cases with positive AFB on smear by Z‐N stain. Radiologically guided FNAC with AFB culture is a simple, reliable and practical approach to diagnosing spinal TB lesions. With a high diagnostic yield, it allows immediate initiation of specific treatment, helps to avoid invasive diagnostic procedures, and decreases hospitalization time.
Thin layer compared to direct smear in thyroid fine needle aspiration
Authors: Scurry J. P. , Duggan M. A.
Published: March 2003

Thin layer compared to direct smear in thyroid fine needle aspiration

The efficacy of preparing thyroid fine needle aspirations (FNAs) by the thin layer as opposed to the direct smear method has not been evaluated sufficiently in a regional laboratory setting. At the Foothills Hospital (Calgary, Canada), the method of processing thyroid FNAs was changed from direct smear to thin layer in January 1996. The results of 327 patients who had direct smear from 1994 to 1995 were compared to 401 who had thin layer between 1996 and 1997. While there were no significant differences across a broad range of quality indicators, thin layer showed a trend towards a higher proportion of true benign diagnoses (31%vs 24%), a lower proportion of inadequate specimens (41%vs 50%) and, most importantly, a lower false negative rate (3%vs 9%). In conclusion, the changeover to thin layer did not compromise the interpretation of thyroid FNAs.
Aspiration cytodiagnosis of small cell malignancies found in fine needle aspirate (FNA) of the liver: an immunocytochemical study
Authors: Gupta R. K. , Kenwright D. N. , Naran S. , Lallu S. , Fauck R.
Published: March 2003

Aspiration cytodiagnosis of small cell malignancies found in fine needle aspirate (FNA) of the liver: an immunocytochemical study

In this study the features of small cell malignancies found in the liver by fine needle aspiration cytology (FNAC) and immunostains required for a diagnosis and differential diagnosis are presented. The material consisted of 197 fine needle aspirates which were performed under image guidance between January 1982 to October 1999. Of these, 30 were diagnosed as small cell malignancies. The age of patients ranged between 46 and 68 years. The aspirated material was examined using Papanicolaou‐stained filter preparations and cell blocks, the latter stained with hematoxylin and eosin and a panel of immunoperoxidase stains. The diagnoses based on a correlation of relevant clinical history, cytohistological findings and immunostaining were: metastatic small cell anaplastic carcinoma of lung (n = 6); neuroendocrine tumour (n = 9); non‐Hodgkin's lymphoma (n = 4); well‐differentiated cholangiocarcinoma (n = 2); metastatic carcinoma of the prostate (n = 2); metastatic adenocarcinoma (n = 4) and metastatic carcinoma breast (n = 3). This study emphasizes the wide range of neoplasms that enter into the differential diagnosis of small cell malignancies found in the liver and a correlation of clinical, cytohistological and immunostaining findings which seem to be useful in suggesting a diagnosis.
Aspiration cytology from the pouch of Douglas at hysteroscopy
Authors: Kobilková J. , Kužel D. , Tóth D. , Lojda Z.
Published: March 2003

Aspiration cytology from the pouch of Douglas at hysteroscopy

Eighty‐seven fine needle aspiration cytological samples from 29 patients suffering from irregular perimenopausal uterine bleeding were evaluated. Aspiration cytology was performed prior to hysteroscopy, after distension of the uterine cavity and finally after uterine curettage.

In this paper, cytological examination of fluid from the pelvic content in women with benign endometrial findings is compared with that of patients with adenocarcinoma. Endometrial curettage influenced the cell content of the cytological specimens.
Benign phyllodes tumour vs fibroadenoma: FNA cytological differentiation
Authors: Veneti S. , Manek S.
Published: March 2003

Benign phyllodes tumour vs fibroadenoma: FNA cytological differentiation

The differential diagnosis of fibroadenomas vs phyllodes tumours by fine needle aspiration (FNA) cytology is not possible in the majority of cases. The present study aims to look at common and dissimilar features to allow differentiation, if possible. We reviewed the FNA findings of 18 histologically proven phyllodes tumours and 18 fibroadenomas, checking in each case the epithelial features, the stromal features, and any atypia. Using a semi‐quantitative score assessed by two observers we were able in most cases to distinguish a phyllodes tumour from a fibroadenoma. The most important criteria were larger stromal fragments, numerous plump stromal bare nuclei, and the higher ratio of stromal bare nuclei to epithelial bare nuclei in phyllodes tumours. In the present study, an original diagnosis of phyllodes tumour was made in 7/18 (38.9%) cases but with our criteria this could be improved to 15/18 (83.3%) cases. Therefore, the presence of specific stromal features in a dimorphic cellular pattern should suggest the correct diagnosis and differentiate its appearance from a cellular fibroadenoma.
Rapid (partial) prescreening of cervical smears: the quality control method of choice?
Authors: BROOKE D. , DUDDING N. , SUTTON J.
Published: March 2003

Rapid rescreening of all negative and inadequate smears is the quality control method of choice in the UK. The sensitivity of primary screening of laboratory and individual screeners are major indicators of screening quality and are dependent on the number of false negative smears found by rapid screening for their calculation. High sensitivity may indicate good quality primary screening or poor quality rapid review. Quantifiably high quality rapid rescreening is essential if these sensitivity figures are to be meaningful. A 12‐month study was undertaken in routine practice using the prescreening mode to ascertain the sensitivity of rapid (partial) screening in our department . The final results of smears were compared with those of rapid prescreening. The calculated sensitivity ranged from 92–54% for high‐grade abnormalities and 75–33% for all grades, revealing a wide range of performance between individual prescreeners. Rapid prescreening can identify individuals best suited to rapid screening in routine practice. By using these prescreeners only, the sensitivity of cervical screening could be raised. Rapid (partial) prescreening should be considered as the quality control method of choice.
Good practice in head and neck fine needle aspiration cytology as assessed by CUSUM
Authors: Robinson I. A. , Blackham R. B. , Cozens N. J. , Sharp J.
Published: March 2003

Providing data as evidence of good practice is becoming imperative to meet the demands of professional revalidation and clinical governance. Sensitivity and specificity are common performance measures in fine needle aspiration (FNA) but are vulnerable to discordant analytical methods. We introduce a CUSUM technique and show how it may be used to show attainment and maintenance of proficiency in head and neck (H&N) FNA. In addition, we show how it can be used to compare practices and demonstrate different performance for FNAs from different tissues; a fact that must be recognized by anyone devising minimum performance values.
The escape response of pea aphids to foliar‐foraging predators: factors affecting dropping behaviour
Authors: LOSEY JOHN E. , DENNO ROBERT F.
Published: March 2003

1. The effects of predator species, aphid density, aphid age, diel period, and habitat complexity on the dropping behaviour of the pea aphid Acyrthosiphon pisum were assessed in a series of laboratory and field‐cage experiments.

2. The presence of foliar‐foraging predators significantly increased the proportion of aphids that dropped from alfalfa plants. In the absence of predators, less than 7% of the aphids dropped. Dropping more than doubled (14%) when one of three hemipteran predators, N. americoferus, G. punctipes or O. insidiosus, was present. Nearly 60% of the aphids dropped when the ladybird beetle, Coccinella septempunctata, was present.

3. Adult aphids showed a significantly higher propensity to drop than immature aphids, regardless of the presence or absence of predators. Aphid density had no effect on dropping behaviour.

4. Neither diel period nor habitat complexity had an effect on aphid dropping behaviour. Aphids were significantly more likely to drop in the presence of predators during either the day or night and from either early or late regrowth alfalfa.

5. A review of the factors affecting dropping behaviour, including those elucidated in this study, indicates that the propensity to drop from a plant is influenced by three factors: the risk of predation on the plant, the quality of the resource to be abandoned, and the risk of mortality in the new microhabitat.
Interactions between Operophtera brumata and Tortrix viridana on oak: new evidence from time‐series analysis
Authors: HUNTER MARK D.
Published: March 2003

1. Yearly population estimates of the green oak leaf roller moth, Tortrix viridana (Lepidoptera: Tortricidae), and the winter moth, Operophtera brumata (Lepidoptera: Geometridae), were taken from the pedunculate oak, Quercus robur, from 1951 to 1966 in Wytham Woods, Oxfordshire, U.K. Larval mortality from parasitoids was recorded for both species over the same period.

2. Operophtera brumata population density fluctuated around a constant mean, whereas T. viridana population density exhibited a linear decline over the sampling period. Population counts were subjected to time‐series analysis after the linear decline was removed from the T. viridana data by detrending. Multiple regression models were built so that variation in the per capita rate of increase of each population could be partitioned among (a) current and previous population density, (b) current and previous population density of the second moth species, and (c) rates of larval parasitism.

3. Multiple regression analysis suggested that variation in the per capita rate of increase of O. brumata could be explained by negative feedback from O. brumata density at T–2 (32%), a negative relationship with T. viridana density at T–1 (18%), and a positive relationship with parasitism suffered by T. viridana at T–1 (24%).

4. The T. viridana population time‐series was dominated by a rapid feedback process such that per capita rate of increase at time T was negatively related to population density at time T–1, explaining 53% of variance in population growth rate. Per capita rate of increase was unrelated to larval parasitism or densities of O. brumata.

5. In light of previous life‐table and experimental studies on O. brumata and T. viridana, the current analyses suggest that pupal predation (data not presented) and interspecific competition are significant determinants of O. brumata population growth rates in Wytham Woods. In contrast, T. viridana population growth rates appear to be dominated by rapid negative feedback consistent with intraspecific competition.
Influence of the predatory backswimmer, Notonecta maculata, on invertebrate community structure
Authors: LEON BLAUSTEIN
Published: March 2003

1. The impact of the predator, Notonecta maculata, on invertebrate community structure was investigated by a combination of a natural pool survey, an outdoor artificial pool experiment, and a laboratory prey preference experiment.

2. In a survey of forty natural pools in the Negev Desert, Israel, pelagic/neustonic species richness and overall species richness, but not benthic species richness, were negatively associated with N. maculata density.

3. In the artificial pool experiment, in which the presence or absence of Notonecta was manipulated, Notonecta caused a reduction in the richness of species colonizing the pools. Notonecta strongly reduced densities of the pelagic dipterans, Culiseta longiareolata (often 100% reduction of later‐instar larvae and pupae) and ephydrids. Fewer Culiseta egg rafts were found in Notonecta pools, indicating that part of the observed reduction of Culiseta is not due to consumption of Culiseta larvae by Notonecta, but to habitat selection by ovipositing Culiseta females in response to risk of predation by Notonecta. Notonecta did not affect densities of (benthic) chironomids or the small cladoceran, Ceriodaphnia cf. quadrangula. Laboratory assessments of selectivity by Notonecta for the various prey matched patterns found in the field experiment.

4. This work provides strong evidence that N. maculata is an important organizer of community structure: it strongly reduces or even eliminates larger pelagic or neustonic species, but does not affect densities of small or benthic species.
Critical appraisals allow the analytical review of existing knowledge on current topics of significance in ecological entomology. They should assess the worth or quality of the work in the field and suggest areas for investigation.
Authors: CORNELL HOWARD , HAWKINS BRADFORD , HOCHBERG MICHAEL
Published: March 2003

Summary. Previous studies have synthesized life‐table data from herbivore species to identify general trends in the demography of herbivorous insects. Frequency‐based analyses were used to ascertain which of five mortality sources (enemies, plant factors, competition, weather, intrinsic developmental failure) and which of five ecological characteristics of herbivores (feeding biology, invasion status of the herbivore, latitude, cultivation, and successional status of the habitat) had important influences on mortality patterns.

Here these results are reinforced with a quantitative analysis that relies on actual numbers of herbivores killed at different developmental stages by each of the five mortality sources in different ecological settings. We also examine the relationship between taxonomic category (Coleoptera, Diptera, Lepidoptera, and Hymenoptera) and mortality.

The analysis identified developmental changes of herbivores as having an important influence on sources of mortality; feeding biology, latitude, and cultivation status also influenced the distribution of mortality sources. Other aspects of the herbivores’ ecology and taxonomy had limited effects.

Natural enemies were identified as the most important mortality source overall, and their importance increased from the early larval stages to the pupal stages. They also kill more exophytic insects than endophytic insects, and kill a higher proportion of insects in cultivated habitats than in natural habitats.

Weather kills more temperate‐zone immatures than tropical/subtropical immatures.

The results of the quantitative analysis generally confirm the earlier frequency‐based tests.

Several predictions that can serve as the foundation of an empirically‐based theory of herbivore demography are offered: (1) natural enemies are the dominant cause of mortality in exophytic herbivore populations and may compete more intensely than on endophytics; (2) plant factors and enemies play a more balanced role in endophytic populations; (3) exophytic species should be particularly susceptible to top‐down effects, especially in agroecosystems; (4) plant defences will often have sublethal effects, but when they are lethal they will be most important as the hatchling larva is just getting established on the plant.

These predictions should be viewed as a challenge to engage in a broader way of thinking about herbivore demography.
Mate preference for novel partners in the cricket Gryllus bimaculatus
Authors: Bateman Philip W.
Published: March 2003

Abstract.1. To benefit from the putative genetic advantages of multiple mating with multiple partners, female insects would be expected to select against mating with the same male twice when another potential partner is present.

2. This paper examined whether female Gryllus bimaculatus (Gryllidae) preferred to mate with a novel partner over a partner with which they had mated previously.

3. Females presented with a choice preferred significantly to mate with novel males over previously mated males, and preferred to do so even when the potentially confounding influence of male–male competition was controlled for.

4. The potential advantages of such a mate choice pattern and possible ways in which the choice is mediated are discussed.
Evidence for host‐associated races in a gall‐forming midge: trade‐offs in potential fecundity
Authors: Rossi Anthony M. , Stiling Peter , Cattell Maria V. , Bowdish TodD. I.
Published: March 2003

Abstract.1. The gall midge,Asphondylia borrichiae, attacks the terminals of three plants in the aster family:Borrichia frutescens,Iva frutescens, andI. imbricata.

2. In the field,Borrichiasuffers the highest rate of galling andI. imbricatathe lowest. Common garden experiments also revealed highly significant differences in the attack rates of the three host species byAsphondylia. However, these differences depended on the source of the attacking midge population.

3. Midges collected fromBorrichiaandI. frutescensattacked the host in which they developed almost exclusively, whereas those fromI. imbricataattacked bothIvaspp.

4. EachAsphondylialarva develops in its own chamber within a gall.Borrichiagalls were 2.5–3.5‐fold less crowded than those fromI. imbricataandI. frutescens, respectively. Consequently, midges that developed inBorrichiawere significantly larger and eclosed with 30–40% more eggs than those that developed inI. imbricataandI. frutescens, respectively.

5. Although performance ofAsphondylialarvae was lowest on the twoIvaspp., especiallyI. frutescens, these hosts may provide an escape from natural enemies as a trade‐off for reduced offspring performance.

6. Differences in host‐plant species phenology may reduce gene flow among host‐associated populations ofAsphondylia, thereby favouring the formation of races at the level of plant genus.
Endophagous insects and structural niches on plants: ecology and evolutionary consequences
Authors: Eber Sabine , Knoll Steffi , Brandl Roland
Published: March 2003

1. The endophagous weevil Lixus elongatus was studied on two Carduus species in order to look for the impact of a structural gradient in host plant stem diameter on the life cycle and the genetic structure of this species.

2. Body size of L. elongatus females was correlated positively with their fecundity and the stem diameter at the location of oviposition.

3. Emerging individuals showed a significantly positive relationship of body size with the stem diameter at their pupation and emergence site. Mating behaviour was positively size‐assortative.

4. Allozyme analyses indicated a gradient of genetic differentiation along body size classes and a decreasing heterozygosity with decreasing body size.

5. The results led to the conclusion that a structural gradient in plants can promote body size variability in an endophagous herbivore through phenotypic constraints of the host plant and the herbivore. As size‐assortative mating translates this variability into differential gene flow between individuals of different body size, this could provide the raw material for speciation processes. Within a single host plant patch, however, further processes are necessary to split the existing genetic gradient into separate gene pools.
Larval population density affects female weight and fecundity in the dung beetle Aphodius ater
Authors: Hirschberger Petra
Published: March 2003

1. Competition for food at high densities during larval development leads to reduced adult weight in the northern temperate dung beetle Aphodius ater.

2. Analysis of female beetles caught in the field showed that numbers of eggs and total egg load per female were correlated positively with beetle size.

3. Female beetles reared at different population densities during larval development in the laboratory were analysed with regard to their lifetime fecundity and reproductive lifespan.

4. High population densities during development had a negative influence on the number of eggs per female and on reproductive lifespan. Lifetime fecundity was correlated positively with female weight.

5. It was concluded that competition during larval development in the first generation of offspring will result in a lower number of offspring in the second generation in Aphodius ater, and thereby reduce parental fitness.
Nest site preference and success in a gregarious, ground‐nesting bee Dieunomia triangulifera
Authors: Wuellner Clare T.
Published: March 2003

1. The characteristics of preferred nest sites of the solitary bee Dieunomia triangulifera, which nests gregariously in alluvial soil, were investigated. Nest presence was used as an indication of preference. In those cases where nests were more than a few days old, therefore, this study also investigated nest success.

2. Independent variables tested were soil surface moisture, presence of nesting conspecifics, smooth vs. irregular soil surface, distance to visual landmarks, percentage of vegetation cover, soil compaction, vehicular traffic, soil surface temperature, and light intensity.

3. Bees preferred to nest in moist, compact soil with an irregular surface. More bees nested near visual landmarks and in places with little or no vegetation. They preferred nesting in areas with warmer soil surface temperatures and brighter illumination. The presence of nesting conspecifics did not influence nesting decisions. Vehicular traffic also seemed to have no impact on nest initiation but did seem to have a negative impact on nest success.

4. Although it might seem that ground‐nesting bees should not be limited by nesting sites, relatively little of the study area met all their apparent criteria. This might account, in part, for gregarious nesting in this species.
Preference–performance linkage in the neotropical spittlebug Deois flavopicta, and its relation to the Phylogenetic Constraints Hypothesis
Authors: Pires C. S. S. , Price P. W. , Fontes E. G.
Published: March 2003

1. Predictions from the Phylogenetic Constraints Hypothesis were tested for the first time in a tropical system using the pasture pest Deois flavopicta Stal, which oviposits into the ground and not into plant tissues. The prediction that there is no oviposition preference–larval performance linkage was supported. The absence of such a link provides an evolutionary basis for eruptive population dynamics.

2. The effects of host species and host plant quality on the preference of ovipositing females of D. flavopicta and performance of their offspring on the selected host plants were tested at the population level.

3. Female oviposition behaviour was affected by the presence of the host plant. Females of D. flavopicta showed a strong preference to oviposit close to host plants. The number of eggs was higher in pots containing Brachiaria ruziziensis (121.88 ± 13.70) than in pots containing only the wet oviposition substrate (5.2 ± 1.98) or dry oviposition substrate (0.067 ± 0.067). Ovipositing females did not, however, discriminate between plants of Brachiaria decumbens and Axonopus marginatus and did not show a strong oviposition preference in relation to differences in plant quality (protein and fibre content). They did show oviposition preference for plants under the high watering regime. The mean number of eggs collected from pots with non water‐stressed plants was 60% higher than the mean number of eggs collected on pots with water‐stressed plants.

4. Although females did not show ovipositional preference, spittlebug larval performance, measured as percentage survival and duration of nymphal period, was better on plants of high protein and low fibre content. These results indicate that there is not a linkage between female oviposition preference and subsequent nymphal performance in relation to differences in protein and fibre content in the host plants. There was, however, a limited linkage between oviposition preference and nymphal performance in relation to plant water content. Females showed preference for moist sites that have high survival of newly hatched nymphs.

5. Evidence indicates that for D. flavopicta, the influences of natality and female oviposition behaviour in response to plant quality are not the major factors driving population outbreaks, which is in accordance with the Phylogenetic Constraints Hypothesis.
The effect of egg load and host deprivation on oviposition behaviour in aphidophagous hoverflies
Authors: Sadeghi H. , Gilbert F.
Published: March 2003

1. Two species of aphidophagous hoverfly, Episyrphus balteatus and Syrphus ribesii, were tested for the effects of egg load and host deprivation on oviposition choices.

2. Egg load affected the total number of eggs laid in E. balteatus but not in S. ribesii, however it did not affect the proportion laid on any one aphid in E. balteatus but did affect the proportion laid on any one aphid in S. ribesii. The rank order of preferences remained unchanged by age or host deprivation.

3. The dominant effects on host choices were aphid species (in both syrphids) and presentation order (in E. balteatus).

4. Being deprived of hosts increased egg load substantially in E. balteatus, and increasing time of deprivation also had an effect on discrimination; there was no effect of host deprivation in S. ribesii.

5. Reasons for these patterns are discussed.
Can imperfect host discrimination explain partial patch exploitation in parasitoids?
Authors: Outreman Y. , Le Ralec A. , Wajnberg E. , Pierre J. S.
Published: March 2003

1. Host discrimination by Aphidius rhopalosiphi (De Stefani Perez) (Hymenoptera: Braconidae) was first studied on the grain aphid Sitobion avenae (Fabricius) (Homoptera: Aphididae). Females tended to avoid oviposition in hosts parasitised 3 h earlier. No evidence of host discrimination ability on freshly parasitised hosts was suggested, however, and ovipositional experience had no effect on host discrimination.

2. The effects of host discrimination ability on the exploitation strategy of patches containing different proportions of unparasitised hosts and hosts parasitised for 3 h were studied. Females spent less time on patches with a higher proportion of parasitised hosts, reflecting the females' ability to perceive the potential profitability of the patch. This ability may be based on the nature of the hosts encountered (unparasitised or parasitised).

3. Incomplete exploitation of unparasitised hosts was also observed. It seems that this partial exploitation is related to the inability of A. rhopalosiphi to recognise freshly parasitised hosts. As a female may experience a risk of self‐superparasitism during patch depletion, this could promote early departure from incompletely exploited patches.

4. The effect of previous experience on the patch exploitation strategy was also assessed. Females were tested twice on two patches of the same quality. Results suggested that the experience acquired during a previous visit led the females to leave the patch sooner and to lay fewer eggs in parasitised hosts.

5. Patch exploitation strategy may therefore be the result of different factors such as host discrimination and experience. The evolutionary consequences of the results are discussed.
Limiting the potential for intraspecific competition: regulation of Trioza eugeniae oviposition on unexpanded leaf tissue
Authors: Luft P. A. , Paine T. D. , Redak R. A.
Published: March 2003

1. Trioza eugeniae (Homoptera: Triozidae) females oviposit pre‐ ferentially on the margin of young, incompletely expanded Syzygium paniculatum leaves. As the density of eggs on the leaf increases, females will oviposit on the surface of the leaf blades.

2. The survivorship of eggs laid on the abaxial leaf midrib and near the abaxial leaf margin was significantly greater than that of eggs laid on the leaf margin.

3. Controlled environment studies demonstrated that maximum carrying capacity for T. eugeniae nymphs on a fully expanded leaf is approximated closely by the number of eggs that can be laid on the margin of a young, unexpanded leaf.

4. In field populations, nymphal densities fell below the hypothetical carrying capacity calculated from laboratory studies on 71% of the leaves examined.

5. The leaf margin appears to be a proximal cue used by ovipositing females for resources available to developing nymphs. Females that limit oviposition to available leaf margins appear to improve the probability of survival of their progeny through reduced intraspecific competition.
Effect of soil hardness on aggression in the solitary wasp Mellinus arvensis
Authors: Ghazoul Jaboury
Published: March 2003

1. Two alternative nesting strategies are exhibited by soil‐nesting Mellinus arvensis females, digging a new nest (diggers) and searching for an old unoccupied burrow (searchers). Wasps appear unable to distinguish between occupied and unoccupied nests, and aggressive interactions between searchers and nest owners at nest entrances are frequent.

2. In aggressive encounters, there is an advantage in size and residency status.

3. The costs associated with the two nesting strategies vary across geographically separated populations: nest digging incurs costs in terms of time, and these vary according to the hardness of the soil substrate; nest searching is variably costly in terms of risk of injury in aggressive encounters with nest‐owning females.

4. Individual female wasps can switch between nesting strategies, and thus soil hardness, by affecting the cost of nest construction, affects the relative frequencies of the two nesting strategies within a population, favouring an increase in the searching strategy. This, in turn, affects the frequency and intensity of aggression between females at a nesting aggregation.

5. Female body size is correlated with soil hardness. As aggressive encounters are more frequent in sites with hard soil substrates, there is increased selective advantage in having large body size at these sites.

6. Body size is determined primarily by the availability of food resources during larval development, which is, to a degree, a function of the size of the adult female. There is a trade‐off between provisioning a few cells with many provisions in each, leading to the development of few but large adults, as opposed to many cells with few provisions, leading to many small offspring. The relative advantage of these two provisioning strategies is, at least in part, a function of the hardness of the soil substrate.
Microgeographic genetic structure and intraspecific parasitism in the antLeptothorax nylanderi
Authors: Foitzik S. , Heinze J.
Published: March 2003

1. Genetic colony structure of the small central European antLeptothorax nylanderiis affected strongly by ecological constraints such as nest site availability and intraspecific social parasitism.

2. AlthoughL. nylanderiis generally monogynous and monandrous, more than a quarter of all nests collected in a dense population near Würzburg, Germany, contained several matrilines. As shown by microsatellite analysis, the average nest‐mate relatedness in these nests was 0.20. Genetically heterogeneous nests arise from nest take‐over by alien colonies or founding queens, a result of severe competition for nest sites.

3. In summer, more than one‐third of all colonies inhabited several nest sites at a time. Polydomy appears to be rather limited, with two or three nests belonging to a single polydomous colony.

4. Queens appear to dominate male production; only a small fraction (8%) of males was definitively not progeny of the queen present but might have been worker progeny or offspring of another queen.

5. Strong evidence for heterozygote deficiency was found and a total of nine diploid males was discovered in two colonies. These findings suggest deviation from random mating through small, localised nuptial flights.
Reproductive development and maternal effects in the pine weevil Hylobius abietis
Authors: Wainhouse D. , Ashburner R. , Boswell R.
Published: March 2003

1. In a laboratory study of maturation feeding of female pine weevil Hylobius abietis on current and 1‐year‐old stem bark of transplants of Scots and Corsican pine, Norway and Sitka spruce, Douglas fir, and hybrid larch, the length of the pre‐oviposition period was influenced by the species on which weevils fed. The shortest pre‐oviposition period was on hybrid larch (11.8 days) and the longest on Douglas fir (15.5 days).

2. The species on which weevils fed also affected fecundity but there was evidence of a species–year interaction. Over a period of 36 days, most eggs were laid by weevils feeding on current stem of Norway spruce and Corsican and Scots pine and fewest on current stem of Sitka spruce.

3. Significant maternal effects on egg size were observed both in relation to female size and conifer species. The largest eggs were laid on Corsican pine and the smallest on Douglas fir, with no evidence of a trade‐off between number of eggs laid and their size.

4. There was a positive relationship between egg and larval size and between larval size and survival on logs of four conifer species. Residual resistance mechanisms in the bark of recently cut stumps and larval competition are discussed briefly in relation to the importance of the observed maternal effects on weevil population dynamics.
Effects of gender and mating status on self‐directed dispersal by the whitefly parasitoidEretmocerus eremicus
Authors: Bellamy David E. , Byrne David N.
Published: March 2003

1. The impacts of gender and mating on short‐range (< 10 km) dispersal by the whitefly parasitoidEretmocerus eremicusRose and Zolnerowich (Hymenoptera: Aphelinidae) were examined. A fluorescent dust‐marking technique was also tested.

2. In a vertical flight chamber, female flight duration was significantly longer than that of males, and unmated parasitoids flew for longer than mated parasitoids. The mean flight durations were: unmated females 34 min, mated females 10 min, unmated males 7 min, mated males < 1 min.

3. The dispersal behaviour ofE. eremicuswas investigated in the field using fluorescent dust. Before doing so, it was determined in the laboratory that this dust did not affect flight behaviour, was retained over the length of the experiments, and allowed large samples to be processed quickly and inexpensively.

4. In the field, traps were placed along annuli at 3, 5, 7, and 10 m from release points. Eighty‐seven per cent of the 4153 parasitoids captured were males. Sex ratios were near parity on release.

5. The difference in dispersal characteristics between males and females may be resource based, suggesting that certain requirements were met within the field plots for males that were not met for females.

6. Locally, males dispersed in a manner consistent with a simple diffusion model while females engaged in wind‐directed flight soon after leaving release sites. The fact that the genders exhibited dissimilar dispersal characteristics, supports the claim that insect flight, even by small species, can be self‐directed.
Body size as an estimator of production costs in a solitary bee
Authors: Bosch Jordi , Vicens Narcís
Published: March 2003

Abstract 1. Body weight is often used as an estimator of production costs in aculeate Hymenoptera; however, due to differences between sexes in metabolic rates and water content, conversion of provision weight to body weight may differ between males and females. As a result, the cost of producing female progeny may often have been overestimated.

2. Provision weight and body weight loss throughout development were measured in a solitary bee, Osmia cornuta (Latreille), to detect potential differences between sexes in food weight/body weight conversion.

3. Male O. cornuta invest a larger proportion of larval weight in cocoon spinning, and presumably have higher metabolic rates than females during the larval period; however, this is compensated by a slightly longer larval period in females.

4. Overall, body weight loss throughout the life cycle does not differ significantly between sexes. As a result, cost production ratios calculated from provision weights and from adult body weights are almost identical.

5. The validity of other weight (cocoon, faeces) and linear (head width, intertegular span, wing length, cocoon length, and cell length) measures as estimators of production costs is also discussed.

6. Valid estimators of production costs vary across species due to differences in sex weight ratio, cocoon shape, provision size in reference to cell size, and adult body size.
The use of artificial neural networks in ecological analysis: estimating microhabitat temperature
Authors: Bryant Simon R. , Shreeve Tim G.
Published: March 2003

Abstract 1. The thermal environment at the scale in which most species exist is largely unknown, and thus the majority of physiological models is based on meteorological measures of ambient temperature.

2. The use of artificial neural networks in ecological analysis is promoted by using them to model microhabitat temperature.

3. The performance of conventional multiple linear regression is compared with that of artificial neural networks in predicting the temperature profiles of two different microhabitats using ambient temperature, solar radiation, and wind speed as input (independent) variables.

4. In both cases, the artificial neural networks showed a lower mean absolute residual error than multiple linear regression (0.95 °C compared with 1.41 °C, and 0.29 °C compared with 0.50 °C) and a higher correlation (r2) between predicted and observed values (0.832 compared with 0.668, and 0.884 compared with 0.670).

5. An artificial neural network developed to include a microhabitat patch description based on height within patch, substrate, and four classes of per cent vegetation cover performed well (r2 = 0.933, prediction error 95% confidence limits =± 2.5 °C).

6. It is suggested that artificial neural networks are more appropriate than conventional regression‐based approaches for estimating microhabitat temperature.
Lack of evidence for reproductive isolation among ecologically specialised lycaenid butterflies
Authors: Nice C. C. , Fordyce J. A. , Shapiro A. M. , Ffrench‐Constant R.
Published: March 2003

Abstract 1. The evolution of reproductive isolation between recently diverged or incipient species is a critical component of speciation and a major focus of speciation models. In phytophagous insects, host plant fidelity (the habit of mating and ovipositing on a single host species) can contribute to assortative mating and reproductive isolation between populations adapting to alternative hosts. The potential role of host plant fidelity in the evolution of reproductive isolation was examined in a pair of North American blue butterfly species, Lycaeides idas and L. melissa.

2. These species are morphologically distinct and populations of each species utilise different host plants; however they share 410 bp haplotypes of the mitochondrial cytochrome oxidase subunit I (COI) gene, indicating recent divergence.

3. Some populations using native hosts exhibited strong fidelity for their natal host plant over the hosts used by nearby populations. Because these butterflies mate on or near the host plant, the development of strong host fidelity may create reproductive isolation among populations on different hosts and restrict gene flow.

4. Tests of population differentiation using allozyme allele frequency data did not provide convincing evidence of restricted gene flow among populations. Based on morphological differences, observed ecological specialisation, and the sharing of genetic markers, these butterflies appear to be undergoing adaptive radiation driven at least partially by host shifts. Neutral genetic markers may fail to detect the effects of very recent host shifts in these populations due to gene flow and/or the recency of divergence and shared ancestral polymorphism.
Immune expression in a damselfly is related to time of season, not to fluctuating asymmetry or host size
Authors: Yourth Christopher P. , Forbes Mark R. , Smith Bruce P.
Published: March 2003

1. Variation in immune responsiveness within and among species is the subject of the emerging field of ecological immunology. The work reported here showed that individuals ofLestes forcipatusRambur differ in their likelihood of mounting immune responses, and in the magnitude of those responses, against a generalist ectoparasite, the water miteArrenurus planusMarshall.

2. Immune responses took the form of melanotic encapsulation of mite feeding tubes, occurred in the few days after host emergence, and resulted in mites dying without engorging. Such immune responses were more probable and stronger for hosts sampled later rather than earlier in the season. Such responses may act as selection affecting seasonal patterns of egg hatching and larval abundance of mites.

3. Contrary to expectation, metrics of host size (wing length) and wing cell fluctuating asymmetry were not related to the likelihood of immune responses.

4. The importance of season on immune expression of insects has not been explored in detail. These results suggest possible trade‐offs in allocation of melanin (or its precursors) to maturation versus immunity, and indicate the need for studies on the synergistic effects of weather and parasitism on host species that use melanotic encapsulation to combat parasites and pathogens.