bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of maternal diet quality on offspring performance in the rove beetle Tachyporus hypnorum
Authors: KYNEB ANN , TOFT SØREN 
Published: July 2006

Abstract1. The reproductive output of an individual is known to be influenced by diet quality, but the quality of the parent's diet can also influence the performance of the offspring. Dietary maternal effects may interact with the effects of the offspring's diet to produce a variety of response patterns.2. Maternal effects were investigated in a polyphagous predator, the rove beetleTachyporus hypnorum, using three single‐species diets: two low‐quality diets consisting of the aphidsSitobion avenaeandRhopalosiphum padi, and the high‐quality controlDrosophila melanogasterdiet. Offspring of females fed these diets were raised on the same monotypic diets and allowed to reproduce. Several fitness parameters were measured to indicate possible maternal effects in both F1 and F2 generations.3. Maternal diet effects in F1 were found in egg size, hatching success, time to hatching, larval development time, larval survival, and sex ratio. Both aphid diets resulted in smaller eggs. A diet ofR. padiresulted in reduced hatching success, longer time spent in the egg stage, and a female‐biased sex ratio. A maternal diet ofR. padialso prolonged larval development onS. avenaediet, while a maternal diet ofS. avenaedecreased survival on theR. padidiet. These effects were independent of egg size.4. A maternal diet ofR. padienhanced the survival of F1 larvae raised on the same diet. Developmental selection operating through a high egg mortality may be the explanation for this seemingly positive effect.5. Sitobion avenaealone caused a significant reduction in the hatching success of F2 eggs, thus revealing grandmaternal effects.6. The prediction that polyphagous predators are less likely to evolve adaptive maternal effects is supported by the fact that none of the documented maternal effects could be interpreted as adaptive.
Host plant defences and voltinism in European butterflies
Authors: CIZEK LUKAS , FRIC ZDENEK , KONVICKA MARTIN 
Published: July 2006

Abstract1. With respect to seasonal availability for herbivores, plants defended by synthesising qualitative compounds differ from those protected by accumulation of quantitative macromolecules, leaf toughness, and low water and/or nutrient content. While the palatability of the former plants remains relatively constant during the season, the palatability of the latter group decreases with leaf age.2. It was hypothesised that in seasonal temperate environments, quantitative plant defences should restrict the annual numbers of insect generations. To test this hypothesis, European butterflies were used as a model, both non‐corrected regressions and tests controlling for phylogeny were carried out, and potentially confounding factors such as body size or occurrence in short‐season environments were treated as covariables.3. Non‐phylogenetically controlled regressions corroborated that butterflies feeding on quantitatively protected hosts (woody plants + grasses) form fewer generations than species feeding on qualitatively protected forbs. Plant defences fitted voltinism better than butterfly size, and remained significant even after controlling for short seasons. Using independent contrasts, feeding on woody plants plus grasses, and feeding on woody plants only, predicted fewer generations. These patterns, however, applied exclusively for foliage‐feeding species.4. The association between plant defences and voltinism represents a hitherto overlooked pattern in the ecology of temperate herbivores. It may explain why large insects tend to form fewer generations and feed on structurally complex hosts, and why some species remain monovoltine although they are not restricted by short season.
Does variation in female body size affect nesting success in Dawson’s burrowing bee, Amegilla dawsoni (Apidae: Anthophorini)?
Authors: ALCOCK JOHN , SIMMONS LEIGH W , BEVERIDGE MAXINE 
Published: July 2006

Abstract 1. Females of Dawson’s burrowing bees vary in body weight over a twofold range. Despite the potential for differences in body weight to affect several aspects of the competition among nesting females, no clear advantages were documented for larger females.2. Nesting females were not consistently larger than emerging females, nor was there a consistent relationship between body size and the weight of pollen and nectar carried to the nest on provisioning trips. At one nesting location, larger females did not produce larger pre‐pupal offspring nor did they produce offspring at a faster rate than their smaller nesting companions.3. In addition, large body size was not associated with greater success in nest defence despite the fact that nesting females regularly encountered intruders in their burrows. Residency, not body size, determined the outcome of almost all contests for control of a nest burrow. The absence of a large body size effect here appears to stem from an intruder strategy designed to enable nest‐searching females to acquire burrows that had been abandoned through death or dispersal of their original owners rather than securing existing nests through an aggressive takeover strategy.4. Thus, although large body size conveys significant fitness advantages to males, this attribute does not promote female success in either provisioning or defending their nests.
Biodiversity in tropical agroforests and the ecological role of ants and ant diversity in predatory function
Authors: PHILPOTT STACY M. , ARMBRECHT INGE 
Published: July 2006

Abstract1. Intensive agricultural practices drive biodiversity loss with potentially drastic consequences for ecosystem services. To advance conservation and production goals, agricultural practices should be compatible with biodiversity. Traditional or less intensive systems (i.e. with fewer agrochemicals, less mechanisation, more crop species) such as shaded coffee and cacao agroforests are highlighted for their ability to provide a refuge for biodiversity and may also enhance certain ecosystem functions (i.e. predation).2. Ants are an important predator group in tropical agroforestry systems. Generally, ant biodiversity declines with coffee and cacao intensification yet the literature lacks a summary of the known mechanisms for ant declines and how this diversity loss may affect the role of ants as predators.3. Here, how shaded coffee and cacao agroforestry systems protect biodiversity and may preserve related ecosystem functions is discussed in the context of ants as predators. Specifically, the relationships between biodiversity and predation, links between agriculture and conservation, patterns and mechanisms for ant diversity loss with agricultural intensification, importance of ants as control agents of pests and fungal diseases, and whether ant diversity may influence the functional role of ants as predators are addressed. Furthermore, because of the importance of homopteran‐tending by ants in the ecological and agricultural literature, as well as to the success of ants as predators, the costs and benefits of promoting ants in agroforests are discussed.4. Especially where the diversity of ants and other predators is high, as in traditional agroforestry systems, both agroecosystem function and conservation goals will be advanced by biodiversity protection.
Dispersal and foraging behaviour ofPlatygaster californica: hosts can’t run, but they can hide
Authors: DARROUZET‐NARDI ANTHONY , HOOPES MARTHA F. , WALKER JESSE D. , BRIGGS CHERYL J. 
Published: July 2006

Abstract1. Host–parasitoid models often identify foraging behaviour and dispersal distance as important for system persistence.2. Laboratory observations and field trials were used to characterise foraging behaviour and dispersal capability ofPlatygaster californicaAshmead (Platygasteridae), a parasitoid of the gall midgeRhopalomyia californicaFelt (Cecidomyiidae).3. Although foraging parasitoids meticulously searched plants in laboratory observations, none of the laboratory trials resulted in 100% parasitism, and the proportion of parasitism declined as midge egg density increased.4. The field trials showed that the distribution of parasitism over distance from a central release point was hump‐shaped, as predicted by a simple diffusion model. Mean parasitoid dispersal distance was 4.5 m, considerably farther than the 1.7 m mean midge dispersal found in previous work.5. Although the parasitoid appears to search thoroughly for midge eggs and to disperse farther than the midge, the results of this study show how this host–parasitoid system may persist due to spatially variable incomplete parasitism.
The deleterious effects of salinity stress on leafminers and their freshwater host
Authors: SCHILE LISA , MOPPER SUSAN 
Published: July 2006

Abstract 1. Salinity is an important cause of abiotic stress in wetland communities yet little is known about its consequences for freshwater plants and their insect herbivores. The goal of this study was to test the effect of salinity on a leafmining insect, Cerodontha iridiphora, and its herbaceous host plant, Iris hexagona.2. Leafminer performance was evaluated on irises grown in control and saline treatments, and the effects of salinity and herbivory on leaf quality and mortality was measured.3. Leafminer density and size were significantly lower on irises grown in saline water compared with freshwater.4. Both salinity and herbivory accelerated leaf senescence and mortality, and their combined effects increased tissue loss by an order of magnitude compared with controls.5. Leafminers acted as nutrient sinks. The undamaged regions of mined leaves contained 40% less nitrogen than unmined leaves, providing a mechanism for the premature leaf mortality.6. Salinity was detrimental to the performance and survival of both the iris leafminer and its host plant. We propose that glycophytic host plants and their insect herbivores will suffer more than halophytic communities from environmental salinity because they lack the adaptive mechanisms to tolerate this potent physiological stress.
Aminoguanidine prevents arterial stiffening in a new rat model of type 2 diabetes
Authors: Chang K.‐C. , Tseng C.‐D. , Wu M.‐S. , Liang J.‐T. , Tsai M.‐S. , Cho Y.‐L. , Tseng Y.‐Z. 
Published: July 2006

AbstractBackground  Formation of advanced glycation end‐products (AGEs) on collagen within the arterial wall may be responsible for the development of diabetic vascular injury. This study focused on investigating the role of aminoguanidine (AG), an inhibitor of AGE formation, in the prevention of noninsulin‐dependent diabetes mellitus (NIDDM)‐derived arterial stiffening and cardiac hypertrophy in rats.Materials and methods  The NIDDM was induced in male Wistar rats, which were administered intraperitoneally with 180 mg kg−1 nicotinamide (NA) 30 min before an intravenous injection of 50 mg kg−1 streptozotocin (STZ). After induction of diabetes mellitus type 2, animals receiving daily peritoneal injections with 50 mg kg−1 AG for 8 weeks were compared with the age‐matched, untreated, diabetic controls.Results  After exposure to AG, the STZ‐NA diabetic rats had improved aortic distensibility, as evidenced by 18·8% reduction of aortic characteristic impedance (P < 0·05). Treatment of the experimental syndrome with AG also resulted in a significant increase in wave transit time (+23·7%, P < 0·05) and a decrease in wave reflection factor (−26·6%, P < 0·05), suggesting that AG may prevent the NIDDM‐induced augmentation in systolic load of the left ventricle. Also, the glycation‐derived modification on aortic collagen was found to be retarded by AG. The diminished ratio of left ventricular weight to body weight suggested that prevention of the diabetes‐related cardiac hypertrophy by AG may correspond to the drug‐induced decline in aortic stiffening.Conclusions  Long‐term administration of AG to the STZ‐NA diabetic rats imparts significant protection against the NIDDM‐derived impairment in vascular dynamics, at least partly through inhibition of the AGE accumulation on collagen in the arterial wall.
Modulation of HER2 expression by ferulic acid on human breast cancer MCF7 cells
Authors: Chang C. J. , Chiu J. H. , Tseng L. M. , Chang C. H. , Chien T. M. , Wu C. W. , Lui W. Y. 
Published: July 2006

AbstractBackground  The molecular mechanisms underlying the mitogenic effect of ferulic acid (FA), an active compound derived from Angelica sinensis, have never been elucidated. It was the aim of this study to investigate the proliferative effect of FA on human breast cancer cell lines and to elucidate its modulation mechanism on HER2 expression in MCF7 line.Materials and methods  By using MCF7 (oestrogen receptor‐positive; ER+, HER2‐low), BT474 (ER+, HER2‐high), MDAMB231 (ER–, HER2‐low) and SKBR3 (ER–, HER2‐high) human breast cancer cell lines as in vitro models, the mitogenic effects of FA were assessed by trypan blue dye exclusion assay and DNA flow cytometry. Ferulic acid‐modulated cell signalling and HER2 gene expression were evaluated in MCF7 line by Western blot and real‐time RT‐PCR analysis.Results  Ferulic acid ER‐dependently stimulated cell proliferation on MCF7 cells in a concentration‐dependent manner. The HER2 oncogene (one of the prognostic factors of breast cancer) and ESR1 gene (oestrogen receptor‐alpha; ERα) transcription were markedly up‐regulated by FA treatment. Besides, HER2 signalling and its downstream molecules such as AKT and ERK1/2 were involved in FA‐modulated ERα and cyclin D1 synthesis. Addition of anti‐HER2 antibody, trastuzumab, abrogated FA‐enhanced proliferative effect on MCF7 cells, indicated a positive feedback control for the action of HER2 in this setting. The fact that the ER antagonist blocked most of the FA‐up‐regulated HER2 expression, and that trastuzumab down‐regulated ERα gene expression, suggested a cross‐talk between ERα and HER2 signalling on MCF7 cells.Conclusions  The authors’ conclude that FA causes human breast cancer cell proliferation by up‐regulation of HER2 and ERα expression.
Carbon and nitrogen stocks in relation to organic matter fractions, aggregation and pore size distribution in no‐tillage and conventional tillage in northern France
Authors: Oorts Katrien , Bossuyt H. , Labreuche J. , Merckx R. , Nicolardot B. 
Published: July 2006

SummaryThe magnitude of and mechanisms for long‐term differences in soil organic matter stocks under no‐tillage and conventional tillage are still relatively poorly known. We quantified differences in total C and N stocks after 32 years of no‐tillage (NT) and conventional tillage (CT) in plots with a long‐term cultivation history before differentiation and the same annual C and N returns to the soil. The role of physical protection of organic matter (OM) in these stock differences was further investigated by examining the changes at different levels of structural complexity, i.e. organic matter fractions, aggregation and pore‐size distribution. Four structural zones were sampled: loose and dense soil zones under CT and the 0–5 cm (rich in OM) and 5–20 cm (massive structure) soil layers under NT. The C and N stocks, calculated for an equivalent mass of dry soil, were only 10–15% larger under NT than under CT. Mineral‐associated N and particulate organic matter accounted for about 50% of the difference in N stocks. However, 66% of the total difference in C stocks was due to differences in the particulate organic matter (58%) and free residues (8%) fractions. The additional C and N under NT were almost exclusively situated in aggregates larger than 250 μm in diameter. Our results suggest that physical protection of OM under NT contributes significantly to the differences in C and N stocks between NT and CT by (i) enhanced macroaggregate formation in the 0–5 cm layer due to greater microbial activity and OM content and (ii) a better protection of soil organic matter in the 5–20 cm layer due to the presence of small pores and lack of soil disruption by tillage or climate.
Humus structure during a spruce forest rotation: quantitative changes and relationship to soil biota
Authors: Chauvat M. , Ponge J. F. , Wolters V. 
Published: July 2006

SummaryTemporal dynamics of edaphic communities affect numerous processes in forests and also strongly influence the soil’s organic matter status. We have linked long‐term changes in the formation of organic matter (using humus micromorphological analyses) to changes in the soil’s community structure during a spruce forest cycle on acid soil. The study was carried out at four sites of different age‐classes in the Tharandter forest, Germany. The composition of the deeper humus layers (OH, A) was stable. Herbaceous litter, recent spruce litter, fragmented spruce litter, decomposed litter and faeces and fungi, which contributed to the organic layer (OL and OH horizon), significantly changed during the forestry cycle, especially with the shift from the early stage to intermediate stages. Parallel changes of the faunal assemblage of the soil showed quantitative relations between major stages of the forest development, humus dynamics and soil community composition. The herbaceous litter was correlated with surface‐dwelling Collembola and microbial properties with faeces and fungi. Our results suggest that the long‐term stability of deep organic layers provides a refuge for decomposers and detritivores that allows a rapid response to both adverse and favourable conditions, taking place in OL and OF layers. Furthermore, the opening of the canopy in mature stands allows the decomposers to adapt to changes in resource input long before the collapse of the forest.
Priming the productivity pump: flood pulse driven trends in suspended algal biomass distribution across a restored floodplain
Authors: AHEARN DYLAN S. , VIERS JOSHUA H. , MOUNT JEFFREY F. , DAHLGREN RANDY A. 
Published: July 2006

Summary1. Chlorophyll a (Chl a) distribution across a 0.36 km2 restored floodplain (Cosumnes River, California) was analysed throughout the winter and spring flood season from January to June 2005. In addition, high temporal‐resolution Chl a measurements were made in situ with field fluorometers in the floodplain and adjacent channel.2. The primary objectives were to characterise suspended algal biomass distribution across the floodplain at various degrees of connection with the channel and to correlate Chl a concentration and distribution with physical and chemical gradients across the floodplain.3. Our analysis indicates that periodic connection and disconnection of the floodplain with the channel is vital to the functioning of the floodplain as a source of concentrated suspended algal biomass for downstream aquatic ecosystems.4. Peak Chl a levels on the floodplain occurred during disconnection, reaching levels as high as 25 μg L−1. Chl a distribution across the floodplain was controlled by residence time and local physical/biological conditions, the latter of which were primarily a function of water depth.5. During connection, the primary pond on the floodplain exhibited low Chl a (mean = 3.4 μg L−1) and the shallow littoral zones had elevated concentrations (mean = 4.6 μg L−1); during disconnection, shallow zone Chl a increased (mean = 12.4 μg L−1), but the pond experienced the greatest algal growth (mean = 14.7 μg L−1).6. Storm‐induced floodwaters entering the floodplain not only displaced antecedent floodplain waters, but also redistributed floodplain resources, creating complex mixing dynamics between parcels of water with distinct chemistries. Incomplete replacement of antecedent floodplain waters led to localised hypoxia in non‐flushed areas.7. The degree of complexity revealed in this analysis makes clear the need for high‐resolution spatial and temporal studies such as this to begin to understand the functioning of dynamic and heterogeneous floodplain ecosystems.
Cell death in lake phytoplankton communities
Authors: AGUSTÍ SUSANA , ALOU EVA , HOYER MARK V. , FRAZER THOMAS K. , CANFIELD DANIEL E. 
Published: July 2006

Summary1. The fraction of living and dead phytoplankton cells in seven Florida lakes was assessed by using the cell digestion assay, a non‐staining membrane permeability test. The cell digestion assay is an effective method to analyse cell viability in complex natural phytoplankton communities. 2. The lakes examined ranged widely in phytoplankton abundance and community composition. The variability in the percentage of living cells (% LC) was high among the taxonomic groups forming the different phytoplankton communities, ranging from 19.7% to 98% LC. 3. All cells within single cyanobacteria filaments were determined to be either dead or alive, suggesting physiological integration of the cells within colonies. 4. Within each lake, the dominant taxa generally exhibited the highest proportion of living cells. A high proportion of living cells was found to be a characteristic of the different taxa forming the communities of eutrophic lakes. The average value for the % LC for all groups comprising the phytoplankton communities in each of the lakes ranged from 29.9 ± 7.2 to 80.4 ± 4.0 (mean ± SE) and varied strongly and positively with chlorophyll a concentration. 5. These results suggest phytoplankton cell death to be an important process structuring phytoplankton communities in lakes, particularly in oligotrophic ones.
Habitat selection in spatially heterogeneous environments: a test of foraging behaviour in the clonal submerged macrophyte Vallisneria spiralis
Authors: XIAO KEYAN , YU DAN , WANG JINWANG 
Published: July 2006

Summary1. To test whether clonal macrophytes can select favourable habitats in heterogeneous environments, clonal fragments of the stoloniferous submerged macrophyte Vallisneria spiralis were subjected to conditions in which light intensity and substratum nutrients were patchily distributed. The allocation of biomass accumulation and ramet production of clones to the different patches was examined.2. The proportion of both biomass and ramet number of clones allocated to rich patches was significantly higher than in poor patches. The greatest values of both clone and leaf biomass were produced in the heterogeneous light treatment, in which clones originally grew from light‐rich to light‐poor patches, while clones produced the most offspring ramets in the treatments with heterogeneous substratum nutrients. Similarly, root biomass had the highest values in nutrient‐rich patches when clones grew from nutrient‐rich to nutrient‐poor patches.3. The quality of patches in which parent ramets established significantly influenced the foraging pattern. When previously established in rich patches, a higher proportion of biomass was allocated to rich patches, whereas a higher proportion of ramet number was allocated to rich patches when previously established in poor patches.4. Results demonstrate that the clonal macrophyte V. spiralis can exhibit foraging in submerged heterogeneous environments: when established under resource‐rich conditions V. spiralis remained in favourable patches, whereas if established in adverse conditions it could escape by allocating more ramets to favourable patches.