bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytotoxicity of materials used in perforation repair tested using the V79 fibroblast cell line and the granulocyte‐macrophage progenitor cells
Authors: Souza N. J. A. , Justo G. Z. , Oliveira C. R. , Haun M. , Bincoletto C.
Published: September 2010

Aim  To compare the cytotoxicity of materials used to repair perforations using permanent V79 fibroblasts and murine granulocyte‐macrophage progenitor cells (CFU‐GM).

Methodology  Set specimens from amalgam, glass–ionomer, SuperEBA, N‐Rickert, MTA and gutta‐percha were eluted with culture medium for 72 h and their cytotoxicities were assessed by incubating the extracts with V79 and bone marrow‐derived progenitors for 24 h and 7 days, respectively. Cytotoxicity on V79 cells was judged using the total nucleic acid content (NAC), neutral red uptake (NRU) and reduction of the tetrazolium salt (MTT). The number of bone marrow CFU‐GM colonies determined in clonal cultures stimulated with recombinant murine granulocyte‐macrophage colony‐stimulating factor was used to assess cytotoxicity to progenitor cells. Statistical analyses were conducted using the one‐way analysis of variance and Tukey's test where appropriate.

Results  All materials were cytotoxic in both cell systems; however, CFU‐GM was more sensitive to the extracts than V79 cells. A similar rank order of toxicity was observed in V79 cells using the NAC and the MTT assays: glass–ionomer > N‐Rickert ≅ SuperEBA > gutta‐percha > amalgam ≅ MTA (P < 0.05). In contrast, the NRU test exhibited a lower sensitivity to MTA, gutta‐percha and amalgam extracts. In the clonal culture assay, the toxicity was less pronounced in the presence of gutta‐percha, SuperEBA and MTA. Similar cellular responses were found by placing the set specimens directly in the clonal culture dishes.

Conclusions  The sensitivity of toxicity depended on the choice of the endpoint and the cell‐culture system. Nevertheless, MTA was ranked as the least cytotoxic cement in both cell systems.
From molecules to ecosystems through dynamic energy budget models
Authors: Nisbet R. M. , Muller E. B. , Lika K. , Kooijman S. A. L. M.
Published: September 2010

1. Dynamic energy budget (DEB) models describe how individuals acquire and utilize energy, and can serve as a link between different levels of biological organization.

2. We describe the formulation and testing of DEB models, and show how the dynamics of individual organisms link to molecular processes, to population dynamics, and (more tenuously) to ecosystem dynamics.

3. DEB models offer mechanistic explanations of body‐size scaling relationships.

4. DEB models constitute powerful tools for applications in toxicology and biotechnology.

5. Challenging questions arise when linking DEB models with evolutionary theory.
Metapopulation structure depends on spatial scale in the host‐specific moth Wheeleria spilodactylus (Lepidoptera: Pterophoridae)
Authors: Menéndez Rosa , Thomas Chris D.
Published: September 2010

1. The distribution and dynamics of a host‐specific moth Wheeleria spilodactylus were studied between 1998 and 1999 at a hierarchy of spatial scales: geographic (c. 8000 km2), regional (c. 35 km2), subregional (mean c. 12 km2) and local (c. 0·03 km2). We tested the hypothesis that resource quantity and isolation would assume different levels of importance at different scales of analysis, with respect to habitat occupancy and population turnover.

2. Experimental releases in occupied and empty habitats showed that W. spilodactylus dispersal was very rare over distances in excess of 100 m, and that relatively large plants were more likely to be colonized.

3. The host‐plant distribution was very fragmented and the moth did not occupy the entire distribution of its host‐plant at any of the spatial scales studied. At most spatial scales, occupancy decreased with isolation and increased with habitat quantity.

4. Colonization was most likely to occur in non‐isolated habitat patches at the regional scale, in patches with large numbers of plants at the subregional scale, and in patches with large plants at the local scale. Relatively isolated populations were more likely to go extinct at the subregional scale of analysis.

5. At a geographic scale, the distribution apparently depends on metapopulation persistence, which itself depends principally on the amount of habitat in each region. At regional and subregional scales, distributions and dynamics reflect colonization–extinction dynamics within metapopulations; these are affected by the interaction of habitat quantity (number and size of host‐plants) and isolation. At the local scale, distributions and dynamics are affected by relatively frequent movements of individuals between resource patches (influenced by behavioural choices).

6. Long‐term metapopulation dynamics of the moth also reflect population dynamics of its disturbance‐dependent host‐plant Marrubium vulgare. The metapopulation dynamics of the moth are superimposed on the dynamics of its host.
Seed selection by an exceptionally rich community of harvester ants in the Australian seasonal tropics
Authors: Andersen Alan N. , Azcárate Francisco M. , Cowie Ian D.
Published: September 2010

1. We used the composition of nest middens to describe the extent of dietary partitioning in an exceptionally diverse assemblage of harvester ants in the Kakadu region of northern Australia. Eight of the >15 harvester species known from adjacent 30 × 30‐m plots, comprising four species ofMeranoplusand two species each ofMonomoriumandPheidole, maintained conspicuous nest middens.

2. All these eight harvester species are monomorphic (or functionally so in the context of seed collection), with total body length ranging from 2·0 to 5·0 mm. The two species ofMonomoriumare column foragers, whereas the others apparently forage solitarily. Nests averaged 0·1 m2, but were highly patchy both within and between plots.

3. Seed fragments from a total of 33 plant species were identified from 50 middens sampled during the end of the wet season, with up to 19 seed species recorded from a single midden. Seed species diversity was greatest in middens ofMeranoplus minimus,Monomoriumsp. 1 (rothsteinigroup) andPheidolesp. 1 (mjobergigroup), and least in middens of thediversusgroup ofMeranoplus.

4. Despite a high overall diversity of seed species, each harvester species collected primarily two or three seed species (with one exception, all grasses), and there was virtually no overlap in these species between harvesters. The pronounced dietary separation of harvester species was demonstrated by multivariate analysis of midden composition.

5. The extent to which differential seed selection is determined by intrinsic preferences, vs. interactions between, harvester species is unknown, nor is it clear why the diversity of harvester ants is so high. However, it is likely that differential seed selection plays a significant role in species coexistence.
Latitudinal variation in growth of young brown troutSalmo trutta
Authors: Jensen Arne J. , Forseth Torbjørn , Johnsen Bjørn Ove
Published: September 2010

1.A new laboratory‐based growth model for brown trout (Salmo trutta) was used to explore latitudinal variation in growth among natural populations. The model included the effects of differences in ambient temperatures and fish size among populations. Annual growth rates of anadromous brown trout parr from 22 Norwegian populations at 61–70 °N were compared with predictions from the growth model. Published field data from one Spanish, 15 British and four Danish populations at 44–58 °N were included in the analysis to increase the latitudinal range.

2.Among the Norwegian populations, the ratio between observed and predicted growth rates was not significantly different from 1·00 in eight rivers, but was significantly higher in eight, and was significantly lower in six. Observed growth was highest, relative to predicted growth, in the coldest rivers. In Spanish, British and Danish rivers, observed growth did not exceed predicted growth.

3.The ratio between observed and predicted annual growth rate decreased significantly with increasing annual mean temperature. Observed annual growth was higher than predicted growth only in rivers with an annual mean temperature lower than 5·1 °C, and this indicates that some kind of thermal adaptation may occur in trout populations in the coldest rivers.

4.Regression analyses showed that besides the direct effects of temperature and body size predicted by the growth model, annual growth rates were significantly related to annual mean temperature, densities of juvenile salmonids, duration of twilight (average for May–August) and latitude. Adding these variables to the original model increased the explanatory power from 73·9 to 80·6%.
Temporal changes in key factors and key age groups influencing the population dynamics of female red deer
Authors: Albon S. D. , Coulson T. N. , Brown D. , Guinness F. E. , Pemberton J. M. , Clutton‐Brock T. H.
Published: September 2010

1. We use structured demographic accounting to decompose the contribution to the variance in relative population growth between 1971 and 1997 in female red deer on Rum, Scotland, in terms of different fitness components and age categories.

2. During the first 10 years (1971–80) the variance in relative population growth was small (0·00246) as the population grew from 58 to 148 having been culled previously. After this the relative variance in population growth increased to 0·00575 between 1981 and 1989, and increased again to 0·00848 between 1990 and 1997.

3. In the first phase of population growth (1971–80) changes in the birth rate contributed most to the variance in relative population growth (30%), then adult winter survival (23%), with calf summer and calf winter survival contributing less than 10%. Birth rate tended to covary strongly with adult winter survival, and to a lesser extent with calf winter survival.

4. The contribution of birth rate to the variance in relative population growth diminished to less than 5% in both the periods 1981–89 and 1990–97. In contrast, the contribution of adult winter survival increased to 36% in 1980s and 40% in 1990s. At the same time, the covariation of adult winter survival with calf winter survival increased successively to reach 40% in 1990–97.

5. Changes in population age structure were small and contributed little to the variance in relative population growth (≈ 1% over the entire study). In the 1970s the 5–7‐year‐old group contributed most (23%) to the variance in relative population growth, though this covaried with 8–12‐year‐olds. In the 1980s the 8–12‐year‐olds contributed most (27%) and now the covariation was with older animals (> 12‐year‐olds). This pattern persisted in the 1990s, though there was covariation with 5–7‐year‐olds too.

6. Birth rate, calf winter survival and adult winter survival were all density‐dependent. The strength of density dependence within each vital rate did not differ between the 1970s, 1980s and 1990s; however, there were differences in the means of these vital rates relative to population size between the three periods.

7. The implications of temporal changes in the most important vital rates, the ‘key factors’, contributing to the variance in relative population growth rate are discussed.
Life path analysis: scaling indicates priming effects of social and habitat factors on dispersal distances
Authors: Kenward R. E. , Walls S. S. , Hodder K. H.
Published: September 2010

Movements of many animals along a life‐path can be separated into repetitive ones within home ranges and transitions between home ranges. We sought relationships of social and environmental factors with initiation and distance of transition movements in 114 buzzards Buteo buteo that were marked as nestlings with long‐life radio tags.

Ex‐natal dispersal movements of 51 buzzards in autumn were longer than for 30 later in their first year and than 35 extra‐natal movements between home ranges after leaving nest areas. In the second and third springs, distances moved from winter focal points by birds that paired were the same or less than for unpaired birds. No post‐nuptial movement exceeded 2 km.

Initiation of early ex‐natal dispersal was enhanced by presence of many sibs, but also by lack of worm‐rich loam soils. Distances travelled were greatest for birds from small broods and with relatively little short grass‐feeding habitat near the nest. Later movements were generally enhanced by the absence of loam soils and short grassland, especially with abundance of other buzzards and probable poor feeding habitats (heathland, long grass).

Buzzards tended to persist in their first autumn where arable land was abundant, but subsequently showed a strong tendency to move from this habitat.

Factors that acted most strongly in ½‐km buffers round nests, or round subsequent focal points, usually promoted movement compared with factors acting at a larger scale. Strong relationships between movement distances and environmental characteristics in ½‐km buffers, especially during early ex‐natal dispersal, suggested that buzzards became primed by these factors to travel far.

Movements were also farthest for buzzards that had already moved far from their natal nests, perhaps reflecting genetic predisposition, long‐term priming or poor habitat beyond the study area.
Rate‐maximizing optimality models predict when oystercatchers exploit a cohort of the bivalveScrobicularia planaover a 7‐year time span
Authors: Wanink Jan H. , Zwarts Leo
Published: September 2010

The timing of prey exploitation by oystercatcherHaematopus ostralegusL. was predicted from detailed knowledge of the characteristics of its prey, the clamScrobicularia planada Costa.

Growth, mortality and depth distribution of a single cohort ofScrobiculariawere monitored on a tidal flat in the Dutch Wadden Sea during a period of 7 years.

A random search model predicted for every sampling date the encounter rate with buried clams providing oystercatchers vary the depth at which they probe their bill into the substrate. The time needed to handle encountered prey was estimated from experimentally determined relationships of handling time with clam size and handling time with burying depth. Encounter rate, handling time and body weight of the potential prey items were used in an optimal prey choice model to predict the average intake rate of an oystercatcher as a function of probing depth.

The predicted intake rate reached a profitable level only during three restricted periods. During the first period, a relatively high intake rate could only be achieved by probing extremely deeply, and the mortality rate of the clams remained at a low level. During the other two periods, maximal intake rate was reached by probing only the upper few cm of the substrate, and this time there was a high mortality in the prey population.

Although the observed peaks in clam mortality coincided with the predicted exploitation periods, they could not be explained fully by the estimated predation pressure.

Prey switching was predicted and confirmed during several exploitation periods.

Oystercatcher densities during winter peaks in bird abundance showed a tight relationship with predicted maximum intake rates.
Healthy wrinkles for population dynamics: unevenly spread resources can support more users
Authors: C. Patrick Doncaster
Published: September 2010

Resource users have a curvilinear relation of abundance to the richness of their limiting resource, with richness defined by the carrying capacity of renewing resource in the absence of exploitation. The non‐linearity means that local unevenness in the distribution of resources can directly influence the overall abundance of users. This effect is entirely independent of overall resource abundance.

Outcomes are demonstrated for a classical model of consumer aggregations under conditions of ideal and free exploitation. Consumers that make little impact on the stock of their limiting resource can benefit directly from environmental heterogeneity. They can sustain higher abundance in an environment with unevenly spread resources than in one of equivalent richness with an even spread. Positive effects of heterogeneity are reduced by density dependence in the exploitation rate, for example caused by mutual interference between users. Heterogeneity may have a negative impact on abundance for consumers with a more efficient exploitation of resources.

Similar outcomes are predicted for classical models of consumer breeding populations as for consumer aggregations. At still larger scales, unevenness in the distribution of resource patches in metapopulations, and of niches in communities, can increase the abundances of populations and species. Species or communities most likely to benefit from unevenness in their resource carpet are those most vulnerable to local extinction from loss or degradation of their habitat.

These effects illustrate applications of non‐spatial models to spatial contexts. They show how steady‐state predictions are likely to be biased by ignoring any underlying heterogeneity in the environment.
Scale invariant spatio‐temporal patterns of field vole density
Authors: Mackinnon James L. , Petty Steve J. , Elston David A. , Thomas Chris J. , Sherratt ToM. N. , Lambin X.
Published: September 2010

Recent characterizations of the spatial scale of population dynamics have typically considered patterns at a single scale and ignored the possibility that different patterns may arise at different scales. In this study we assessed population densities of field voles with cyclic dynamics in northern England at 147 sites from three spatial scales on five occasions over a 2·5‐year period.

The scale over which densities were similar was estimated by comparing the variance of density at the three scales (< 1 km2, 10 km2, and 70 km2) and by using autocorrelation techniques. Closer sites were more similar in density than more distant sites and the autocorrelations suggested that sites up to within 8–20 km had more similar densities and higher population synchrony than the average similarity for all the sampling sites.

A generalized additive model fitted to all the data showed that the data supported the hypothesis of a travelling wave of vole densities moving through the study area. The model assumed that the wave moved at a constant speed and in a uniform direction. Estimates of the wave’s speed (14 km year−1) and direction (travelling in a direction of 66° from north) were consistent with the estimates which had previously been calculated from a time series of vole densities covering a much smaller spatial area but a longer temporal scale.

The spatio‐temporal pattern of vole densities detected over a small spatial scale therefore appears to extend over much larger scales and occurs despite the fragmentation of suitable vole habitat at local (a few square kilometres) and regional (hundreds of square kilometres) scales.
Constraints on body‐size distributions: an experimental test of the habitat architecture hypothesis
Authors: Leaper Rebecca , Raffaelli Dave , Emes Chas , Manly Bryan
Published: September 2010

Holling (1992) has claimed that a range of mechanisms, including habitat architecture, may be responsible for discontinuities in body‐size distributions across a broad range of spatial and temporal scales.

 We tested this proposition in the marine benthos by manipulating habitat architecture directly. Specifically, we constructed artificial sediments (using glass beads) of uniform large or small particles, to change interstitial pore diameters at two estuarine sites.

 A combination of kernel estimation and smoothed bootstrap re‐sampling showed that there was a high and varaible degree of modality in body‐size (1–5 modes) in the experimental bead treatments and controls and no obvious evidence for a trough at organism size 0·5–1 mm ESD.

 We propose that habitat architecture may not be as intimately related to body‐size patterns as originally claimed, at least at smaller scales where experimental tests are tractable.
Field experiments testing for apparent competition between primary parasitoids mediated by secondary parasitoids
Authors: Morris Rebecca J. , MÜller Christine B. , Godfray H. Charles J.
Published: September 2010

Two field manipulation experiments were performed to look for apparent competition between primary parasitoids of aphids, mediated by shared secondary parasitoids. In each case the frequency of secondary parasitism on a ‘focal’ species was compared in the presence or absence of a ‘treatment’ species and its aphid host.

 In both experiments the focal species was Aphidius ervi (Haliday) attacking Acyrthosiphon pisum (Harris) (pea aphid). In the first experiment the treatment species was Aphidius rhopalosiphi (De Stefani‐Perez) attacking Sitobion avenae (Fabricius) (a grass aphid) and in the second Aphidius microlophii (Pennachio & Tremblay) attacking Microlophium carnosum (Buckton) (nettle aphid).

 No significant effects of either the presence of A. rhopalosiphi or of its host on secondary parasitism of A. ervi were detected in the first experiment.

 In the second experiment, rates of secondary parasitism were estimated twice: a significant effect of treatment was found on the first occasion but not the second. In the former, parasitism was highest in the presence of the treatment species and its host, intermediate when just the host was present, and lowest when both were absent.

 We discuss the evidence for apparent competition in host‐parasitoid communities.
Invasion of a stream food web by a new top predator
Authors: Woodward Guy , Hildrew Alan G.
Published: September 2010

A new top predator, the dragonfly Cordulegaster boltonii Donovan, ‘invaded’ a stream with a well‐described food web.

 The pre‐invasion web was species‐poor but complex, with prevalent intraguild predation, cannibalism and omnivory. Such characteristics differ from expectations based upon the early food web literature, but are consistent with more recent empirical webs and theoretical developments.

 Exhaustive sampling was necessary to describe web structure, with the gut contents of several hundred individuals being required to reach the asymptote of the total number of links for individual species. There was no single ‘standard’ sample size that was applicable for estimating the number of links: sampling ‘x’ guts gave a different fraction of the asymptotic value for different species. Smaller predators were more prone to underestimation of links than larger species higher in the web.

 The number of feeding links, trophic status and the degree of omnivory increased progressively with predator body size, both within and among species. The diet of each predator species (or instar) was effectively a subset of the diet of the next largest predator.

 The invader was extremely polyphagous and fed at all trophic levels. Mean chain length increased by half a link following the invasion. Web complexity, and omnivory in particular, also increased. Pre‐ and post‐invasion webs displayed intervality and rigid circuitry. The resident predators were frequently eaten by the invader, but the only significant predators of C. boltonii were larger conspecifics. Although no species have yet been deleted, there has been a 21% increase in links for a 6% increase in species since the invasion, suggesting that the members of the web had become more tightly packed within niche space. Most prey species were eaten by every predator species (including C. boltonii), indicating the potential for strong apparent competition within the web.
Experimentally fragmented communities are more aggregated
Authors: HOYLE MARTIN
Published: September 2010

I investigated the effect of habitat fragmentation on species richness, aggregation and community dominance and composition for predators and non‐predators at two spatial scales. Two independent experiments were considered, both using a microecosystem of microarthropods inhabiting moss patches.

In the study at a larger spatial scale, species richness was lower in the more fragmented habitats, due possibly to the lack of a metapopulation ‘rescue effect’. In the smaller‐scale study, species richness was again lower in the fragmented habitats, but did not depend on whether a connecting moss ‘corridor’ was complete or broken. Fragmentation affected predators more than non‐predators in both studies.

The degree of aggregation both within and among habitat patches was greater in the fragmented species‐poor communities, especially for predators. Theory suggests that lower migration in the fragmented communities may either (a) lead to greater aggregation and lower species richness simultaneously, or (b) greater aggregation, leading to increased dominance and hence lower species richness.

There was no clear association between community dominance and species richness.

Community composition was affected by fragmentation in both studies, but knowledge of trophic level and mite developmental stage was insufficient to predict these effects.
Are kernels the mustard? Data from global positioning system (GPS) collars suggests problems for kernel home‐range analyses with least‐squares cross‐validation
Authors: HEMSON GRAHAM , JOHNSON PAUL , SOUTH ANDY , KENWARD ROBERT , RIPLEY RUTH , MACDONALD DAVID
Published: September 2010

Kernel‐density estimation (KDE) is one of the most widely used home‐range estimators in ecology. The recommended implementation uses least squares cross‐validation (LSCV) to calculate the smoothing factor (h) which has a considerable influence on the home‐range estimate.

We tested the performance of least squares cross‐validated kernel‐density estimation (LSCV KDE) using data from global positioning system (GPS)‐collared lions subsampled to simulate the effects of hypothetical radio‐tracking strategies.

LSCV produced variable results and a 7% failure rate for fewer than 100 locations (n = 2069) and a 61% failure rate above 100 points (n = 1220). Patterns of failure and variation were not consistent among lions, reflecting different individual space use patterns.

Intensive use of core areas and site fidelity by animals caused LSCV to fail more often than anticipated from studies that used computer‐simulated data.

LSCV failures at large sample sizes and variation at small sample sizes, limits the applicability of LSCV KDE to fewer situations than the literature suggests, and casts doubts over the method's reliability and comparability as a home‐range estimator.
Individual quality mediates trade‐offs between reproductive effort and immune function in tree swallows
Authors: ARDIA DANIEL R.
Published: September 2010

Individual variation in the trade‐off between self‐maintenance and offspring quality was assessed in tree swallows,Tachycineta bicolor, by manipulating reproductive effort while simultaneously immunochallenging breeding females.

An experimental manipulation of parental effort was conducted by creating broods of, on average, three, five and eight nestlings. Breeding females were immunochallenged to mount a humoral immune response to sheep red blood cells (SRBC) and a cell‐mediated response to phytohaemagglutinin (PHA). The consequences of adult decisions on offspring quality were assessed through immune responses to PHA, growth rates and residual body mass of nestlings.

Clutch initiation date, a strong measure of individual quality in tree swallows, was linked with immune responses, with earlier‐nesting, presumably higher quality, females mounting stronger immune responses than did later‐nesting birds. Increased reproductive effort led to decreased parental immune responses. There was a significant interaction between individual quality and reproductive effort treatment, with lower‐quality individuals showing greater depression of humoral immune response to SRBC while raising enlarged broods, suggesting individual‐level variation in trade‐offs.

Breeding females raising enlarged broods tended to raise offspring of similar quality to control females, with only growth rate decreasing with increasing brood size, but not residual nestling body mass or nestling immunocompetence. This suggests that females are maintaining offspring quality at the cost of their own immune system maintenance.
Examination of the large white and small white butterflies (Pierisspp.) for the presence of mustard oils and mustard oil glycosides
Authors: APLIN R. T. , D'ARCY WARD R. , ROTHSCHILD MIRIAM
Published: September 2010

Sinigrin and mustard oils were identified in the pupae of the large white butterfly (Pieris brassicae) and the small white (P. rapae). It is assumed that these substances are sequestered by the larvae from its foodplant and stored. The large white is apparently the more efficient storer of the two, and mustard oils could be detected in the adults, as well as the larvae.
Orcadian rhythm ofOecophylla longinodain relation to territoriality and predatory behaviour
Authors: DEJEAN A.
Published: September 2010

AbstractCircadian rhythms of activity in four societies ofOecophylla longinoda(Latreille) have been studied. Activity is continuous, but diurnal activity is greater than the nocturnal activity. This species is characterized by a strong sense of territoriality and the workers occupy: central territories, trees and immediate surroundings occupied by the society; secondary territories, used for hunting purposes, in natural conditions located on the ground; and intermittent territories in the forest zone (diurnal), scarcely used for hunting, but mainly in relation to the tending of homopterans.

The circadian rhythm of activity can be reversed by artificially lighting certain territories at night (reinforcement by attraction of numerous prey). This reversal can only be obtained progressively. By permanent surveillance of the territories and efficient recruitment, the societies rapidly adapt to fluctuations in the quantity of prey. There is a close correlation between agressive territoriality and predation.
Osmoregulation in a nectar‐feeding insect, the carpenter bee Xylocopa capitata: water excess and ion conservation
Authors: NICOLSON SUSAN W.
Published: September 2010

Abstract The liquid diet and high metabolic water production during flight in the carpenter bee Xylocopa capitata Smith 1854 (Hymenoptera, Anthophoridae) causes a water excess, and this is exacerbated by a low dietary intake of ions. The nectar and pollen of the preferred food‐plants, Virgilia divaricata Adamson and Podalyria calyptrata Willd., and other Fabaceae had low levels of sodium. Analyses of the bees and their body fluids showed that the bees have an exceptionally low Na content, and Na homeostasis seems to depend on recycling almost all Na which enters the rectum. The copious dilute urine (137 mOsm) had Na and K concentrations of only 3.4 and 7.0 ITIM, respectively. Isolated preparations of Xylocopa Malpighian tubules secreted a fluid with a K concentration 10 times that of the haemolymph. This means that recycling of K is as important as that of Na, and the bulk of K resorption probably occurs passively in the ileum. This study is the first to examine hymenopteran Malpighian tubules. Their stimulation by cAMP is indicative of the presence of a diuretic hormone in Xylocopa.
Energetics and foraging behaviour of the European seed harvesting ant Messor capitatus: I. Respiratory metabolism and energy consumption of unloaded and loaded workers during locomotion
Authors: NIELSEN MOGENS GISSEL , BARONI‐URBANI CESARE
Published: September 2010

Abstract The respiratory metabolism of workers of Messor capitatus (Latreille) was measured using standard micro‐Warburg techniques on single individuals. The experiments were carried out at 10, 20, 25, 30 and 40oC, and the respiratory quotient (RQ), measured for the same individuals at 30oC, was found to be 0.77. The specific respiratory rate (y, in μl O2/mg dry weight/h) could be described by the following equation: Iny = ‐2.24 + 0.098r ‐0.258 In W; where T is temperature and W is the dry weight in mg. The Q10 for M. capitatus in the temperature interval 20–30oC was 3.4, a higher value than for other ants.

The energy costs of movement and carrying were determined by using the RQ to convert the continuous measurement of CO2 produced at 30oC by Enfiuran anaesthetized workers (‘resting metabolism’), by running workers and by workers loaded with a 20 mg weight to units of energy. The resting metabolism was 10.0±1.0 mJ/mg fresh weight/h. The cost of running (Y in joule per km) could be described by: Y = 3.865 + 0.363 Wf, where Wf is fresh weight in mg. The cost of transport for all experiments could be expressed as 0.64 × the cost of running.
Energetics and foraging behaviour of the European seed harvesting ant Messor capitatus: II. Do ants optimize their harvesting?
Authors: BARONI‐URBANI CESARE , NIELSEN MOGENS GISSEL
Published: September 2010

Abstract The preference in seed selection by Messor capitatus (Latreille) was studied with artificial seeds (weighted styropore spheres) in the laboratory and with natural seeds in the field. The laboratory experiments showed no strong preference for size of the artificial seeds in the range 3–8 mm (diameter). A mass of about 400 mg was selected when artificial seeds of 5‐5.5 mm were offered at different distances from the nest.

In the field experiments, crushed seeds were placed 2 m from the nest and ants showed a clear preference for the size class 2.0–3.0 mm in diameter, which is much smaller and lighter than the preference for the artificial seeds. The preference of seeds from different plants showed very big variability. There was no correlation between the preference and any of the following variables of the seeds: fresh mass, dry mass, water content, energy content, and nitrogen content. No evidence for energy optimizing in food selection in Messor capitatus was found.

The energetic reward of bringing any seed back to the nest will, under all normal conditions, be much higher than the energetic expenditure. For example, the energetic content in a wheat seed is about 650 Joule, which is sufficient energy for a worker ant of Messor capitatus to carry the seed for a distance of 6.5 km at a temperature of 30oC.
Flight behaviour of the black bean aphid, Aphis fabae, and the cabbage aphid, Brevicoryne brassicae, in host and non‐host plant odour
Authors: NOTTINGHAM STEPHEN F. , HARDIE JIM
Published: September 2010

Abstract. Walking alate virginoparae of Brevicoryne brassicae (L.) and Aphis fabae Scopoli were presented with odours of steam‐distilled extracts of the non‐host plants summer savoury (Satureja hortensis L.) and tansy (Tanacetum vulgare L.) in an olfactometer. No effects of the extracts were observed on B. brassicae. However, A.fabae were repelled by summer savoury and tansy odour; both extracts also masked an attractant response to bean (host plant) odour. In a flight chamber, air permeated with odour from host or non‐host plants was blown over flying alates of both species, with a green, plant‐mimicking target presented once a minute. The incidence of targeted (host‐responsive) flight of B.brassicae was not affected by odour from a growing host plant (Brassica oleoracea) or a non‐host plant tansy. Host plant (Vicia faba) odour did not affect the initial rate of climb or the incidence of targeted flight of A.fabae, but when the bean odour was alternated with odour from non‐host tansy plants a greater number of targeted flights occurred in the host plant odour. The volatile extracts of tansy and summer savoury were also presented to flying A.fabae. Aphids flying in air permeated with tansy odour at 450g plant equivalents initiated fewer targeted flights than when flying in clean air. However, no differences in flight behaviour were observed with summer savoury extract. In a horizontal wind tunnel the tansy extract at 90 g plant equivalents blown across the surface of yellow targets reduced the numbers of alate A.fabae landing. The results indicate that plant odours can affect flight and landing of aphids.
The regulation of growth by locusts through post‐ingestive compensation for variation in the levels of dietary protein and carbohydrate
Authors: ZANOTTO F. P. , SIMPSON S. J. , RAUBENHEIMER D.
Published: September 2010

Summary Post‐ingestive responses to four different diets containing protein and digestible carbohydrate in balanced (7% protein, 7% digestible carbohydrate or 21% protein, 21% digestible carbohydrate) or unbalanced proportions (7% protein, 21% digestible carbohydrate or 21% protein, 7% digestible carbohydrate) were assessed in fifth stadium Locusta migratoria. Amounts eaten, defaecated and grown were measured across the fifth stadium. Results showed that locusts differentially utilized ingested protein and carbohydrate and consequently achieved similar growth on all four diets despite having ingested very different amounts of protein and carbohydrate. Nutrients in excess of requirements were voided from the animal mainly after digestion and absorption from the gut. In the case of excess nitrogen, a major route for removal was through increased uric acid excretion, while for carbohydrate the major removal mechanism was apparently via respiration.
Locomotor activity in adult Pyrrhocoris apterus (Heteroptera) in relation to sex, physiological status and wing dimorphism
Authors: Socha R. , Zemek R.
Published: September 2010

The pattern of locomotor (walking) activity was studied in adult males and females of short‐winged (brachypterous) and long‐winged (macropterous) morph of the flightless bug Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae) under constant laboratory conditions. Walking activity was measured with a computerized video system and analysed with respect to sex, physiological status (reproduction, diapause and reproductive arrest of non‐diapause type) and wing dimorphism of the bugs. The largest duration was observed in the macropterous females with reproductive arrest of non‐diapause type (average 6 h per day) and the shortest duration in diapausing brachypterous females and males (average less than 2 h per day). This was reflected also in the overall time spent by walking during the first 14 days after imaginal ecdysis. The time spent by walking significantly increased in the macropterous morph as the bugs aged, whereas in diapausing brachypters the time spent by walking decreased with age. No linear relationship between walking activity and age was found in reproductive brachypterous morph. The bugs of all experimental groups moved mostly during the photophase and were almost inactive during the scotophase. Thus, walking activity in P. apterus is diurnal, irrespective of the wing morph, physiological status, sex and age. Contrary to the macropterous morph, where the locomotor activity of females during photophase was significantly higher than in males, no significant differences were found between the locomotor activities of brachypterous males and females. The observed differences in locomotor activity are discussed in relation to different roles of two wing morphs in the life history of this heteropteran.
Investment in immune function under chronic and acute immune challenge in an insect
Authors: Siva‐Jothy Michael T. , Tsubaki Yoshitaka , Hooper Rowan E. , Plaistow Stewart J.
Published: September 2010

In this paper we investigate the relationship between the chronic burden of mid‐gut parasites (eugregarine trophozooites) and the effect of an acute haemolymph challenge (a nylon insert) on two important insect immune effector systems (phenol oxidase (PO) and the encapsulation response) in a field‐population of damselflies. PO levels in the haemolymph, and the magnitude of the encapsulation response were maintained, regardless of chronic and subsequent acute experimental immune challenges. The maintenance of these effector systems is therefore probably an important life‐history requirement in these damselflies. Investment in mid‐gut PO levels was significantly negatively related to the animal's chronic parasite burden after an acute experimental challenge in the haemolymph, suggesting that maintaining PO levels across two physiological compartments (haemolymph and mid‐gut) is costly. The results suggest that the immune effector system activity in different physiological compartments in an insect's body is affected by chronic parasite burdens in the face of the demands imposed by an acute immune insult.
Hydrogeological behaviour of some fault zones in a carbonate aquifer of Southern Italy: an experimentally based model
Authors: Celico Fulvio , Petrella Emma , Celico Pietro
Published: September 2010

Complex flow circulation patterns are likely to be present in fault‐controlled groundwater flow systems, such as carbonate aquifers. Nevertheless, not much information is available for faults in carbonates, and their hydrogeological behaviour is often neglected in conceptual and numerical models. The understanding of this aspect of subsurface fluid flow has been improved in a carbonate aquifer, where hydrogeological investigations at site scale demonstrated the existence of fault zones that act as barriers. The hydraulic conductivity of the fault core is as low as that of siliciclastic rocks that represent the regional aquitard of the carbonate aquifer. Despite the lower permeability, the fault zones allow a significant groundwater flowthrough and a good interdependence of piezometric heads upgradient and downgradient of the faults. Because of this discontinuous heterogeneity, the aquifer looks like a basins‐in‐series system, where seasonal springs can be detected along some fault zones, as a function of groundwater level fluctuations.
Apparent partial loss age spectra of Neoarchean hornblende (Murmansk Terrane, Kola Peninsula, Russia): the role of biotite inclusions revealed by 40Ar/39Ar laserprobe analysis
Authors: De Jong Koen , Wijbrans Jan R.
Published: September 2010

Metamorphic hornblende frequently yields spectra with progressively increasing 40Ar/39Ar age steps, often interpreted as caused by partial resetting due to thermally activated radiogenic argon loss by solid‐state diffusion. Yet, in many cases rising Ca/K ratio spectra for such samples imply the presence of minor inclusions of K‐contaminant minerals. To avoid parts of grains with mineral inclusions or compositional zoning we drilled tiny discs from thin sections under a petrographic microscope. Laser step‐heating of drilled biotite‐free hornblende discs yielded flat age and ratio spectra. In contrast, furnace step‐heated hornblende separates from the same samples produced apparent loss age spectra. Moreover, biotite‐free samples yielded flat spectra by laser and furnace dating. Consequently, apparent loss spectra result from degassing of included substantially younger biotite before its hornblende host during laboratory step‐heating; c. 2640 Ma hornblende ages constrain the Murmansk Terrane's cooling.
Cooling in rifting sequences during increasing burial depth due to heat flow decrease
Authors: Ceriani Andrea , Di Giulio Andrea , Fantoni Roberto , Scotti Paolo
Published: September 2010

Two case histories are presented to give evidences for sediment cooling during increasing burial depth due to heat flow decrease at the end of crustal stretching in extensional settings. The first refers to the Lower Cretaceous succession accumulated in a strongly subsiding trough within the Sirt Basin (Libya); the second relates to the Mesozoic succession of the Lombardian Basin (NW Italy) formed during Late Triassic–Early Jurassic rifting of the northern margin of the Adriatic microplate. In both cases, heat flow decreasing at the end of crustal stretching overbalanced the thermal effect of increasing burial depth causing a net cooling of rocks. These examples provide an alternative to exhumation for explaining cooling events recorded by rifting sedimentary sequences.
Submarine reworking of exhumed subcontinental mantle rocks: field evidence from the Lherz peridotites, French Pyrenees
Authors: Lagabrielle Yves , Bodinier Jean‐Louis
Published: September 2010

In the Pyrenees, the lherzolites nowhere occur as continuous units. Rather, they always outcrop as restricted bodies, never more than 3 km wide, scattered across Mesozoic sedimentary units along the North Pyrenean Fault. We report the results of a detailed analysis of the geological setting of the Lherz massif (central Pyrenees), the type‐locality of lherzolites and one of the most studied occurrences of mantle rocks worldwide. The Lherz body is only 1.5 km long and belongs to a series of ultramafic bodies of restricted size (a few metres to some hundreds of metres), occurring within sedimentary formations composed mostly of carbonate breccias originating from the reworking of Mesozoic platform limestones and dolomites. The clastic formations also include numerous layers of polymictic breccias reworking lherzolitic clasts. These layers are found far from any lherzolitic body, implying that lherzolitic clasts cannot derive from the in situ fragmentation of an ultramafic body alone, but might also have been transported far away from their sources by sedimentary processes. A detailed analysis of the contacts between the Lherz ultramafic body and the surrounding limestones confirms that there is no fault contact and that sediments composed of ultramafic material have been emplaced into fissures within the brecciated carapace of the peridotites. These observations bear important constraints for the mode of emplacement of the lherzolite bodies. We infer that mantle exhumation may have occurred during Albian strike‐slip deformation linked to the rotation of Iberia along the proto‐North Pyrenean Fault.
Foraminiferal and δ13C isotopic event‐stratigraphy across the Danian–Selandian transition at Zumaya (northern Spain): chronostratigraphic implications
Authors: Arenillas I. , Molina E. , Ortiz S. , Schmitz B.
Published: September 2010

The Zumaya section, northern Spain, is a suitable candidate to define the Global Stratotype Section and Point for the base of the Selandian Stage (Palaeocene) because of its excellent accessibility, exposure and stratigraphic continuity. Uncertainties exist, however, with regard to the stratigraphic horizon where to place the Danian/Selandian (D/S) boundary. Five potential stratigraphic horizons (HDS1 to HDS5) to define the D/S boundary have been identified at Zumaya, based on integrated stratigraphic studies that include quantitative planktic and benthic foraminiferal results, as well as δ13C isotopic and lithological data. Two of these horizons (HDS2 and HDS4) placed in Zone C26r appear to have particularly good potential for serving as the D/S boundary marker, because they may represent significant global palaeoceanographic, palaeoclimatic and eustatic events.