bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological appraisal of Collembola phylogeny with special emphasis on Poduromorpha and a test of the aquatic origin hypothesis
Authors: D’Haese Cyrille A. 
Published: October 2003

Phylogenetic relationships within Collembola were determined through the cladistic analysis of 131 morphological characters and 67 exemplar taxa representing the major families of the group, with special emphasis on Poduromorpha. The results show that the order Poduromorpha is monophyletic and the sister group to the remaining Collembola, with Entomobryomorpha monophyletic and the sister group to the clade Neelipleona + Symphypleona. In Entomobryomorpha, Actaletidae is the sister group of the remaining families. In Poduromorpha, Tullbergiinae is monophyletic as well as Onychiurinae and the group Tetrodontophorinae + Onychiurinae which is the sister group of the remaining Poduromorpha; Tetrodontophorinae is paraphyletic; Onychiuridae is polyphyletic; Isotogastruridae is not an intermediate between Poduromorpha and Entomobryomorpha, it is the sister group of Tullbergiinae; Odontellidae is monophyletic and the sister group to the clade Neanuridae + Brachystomellidae; in Neanuridae, Frieseinae and the group Pseudachorutinae + Morulinae + Neanurinae are monophyletic; Morulinae is the sister group of Neanurinae; Pseudachorutinae is paraphyletic; Hypogastruridae is polyphyletic;Podura aquatica(Poduridae) is not ‘primitive’, it clusters with the generaXenyllaandParaxenyllain Hypogastruridae. On the basis of these relationships and the position of the aquatic species, the most parsimonious hypothesis is a terrestrial edaphic origin for the springtails.
Elevational gradients of small mammal diversity on the northern slopes of Mt. Qilian, China
Authors: Li Jun Sheng , Song Yan Ling , Zeng Zhi Gao 
Published: October 2003

ABSTRACTAim  Small mammal species richness and relative abundance vary along elevational gradients, but there are different patterns that exist. This study reports the patterns of distribution and abundance of small mammals along the broader elevational gradient of Mt. Qilian range.Location  The study was conducted in the Mt. Qilian range, north‐western China, from June to August 2001.Methods  Removal trapping was conducted using a standardized technique at 7 sites ranging between 1600 and 3900 m elevation within three transects. Correlation, regression and graphical analyses were used to evaluate the diversity patterns along this elevational gradient.Results   In total, 586 individuals representing 18 nonvolant small mammal species were collected during 20 160 trap nights. Species composition was different among the three transects with 6 (33%) of the species found only within one transect. Elevational distribution and relative abundance of small rodents showed substantial spatial variation, with only 2 species showing nonsignificant capture frequencies across elevations. Despite these variations, some general patterns of elevational distribution emerged: humped‐shape relationships between species diversity and elevation were noted in all three transects with diversity peaks at middle elevations. In addition, relative abundance was negatively correlated with elevation.Conclusions  Results indicate that maximum richness and diversity of nonvolant small mammals occurred at mid‐elevations where several types of plants reached their maximum diversity and primary productivity, and where rainfall and humidity reached a maximum. It is demonstrated that the mid‐elevation bulge is a general feature of at least a large portion of the biota on the Mt. Qilian range.
Are there latitudinal gradients in species turnover?
Authors: Koleff Patricia , Lennon Jack J. , Gaston Kevin J. 
Published: October 2003

ABSTRACTAim  To examine the effect on the observed relationship between spatial turnover and latitude of both the measure of beta diversity used and the method of analysis.Location  The empirical analyses presented herein are for the New World.Methods  We take the spatial distributions of the owls of the New World as an exemplar data set to investigate the patterns of beta diversity across latitudes revealed by different analytical methods. To illustrate the strengths and weaknesses of alternative measures of beta diversity and different analytical approaches, we also use a simple random distribution model, focusing in particular on the influence of richness gradients and landmass geometry.Results  Our simple spatial model of turnover demonstrates that different combinations of analytical approach and measure of beta diversity can give rise to strikingly different relationships between turnover and latitude. The analyses of the bird data for the owls of the New World demonstrate that this observation extends to real data.Conclusions  For the particular assemblage considered, we present strong evidence that species richness declines at higher latitudes, and there is also some evidence that species turnover is greater nearer the equator, despite conceptual and practical difficulties involved in analysing spatial patterns of species turnover. We suggest some ways of overcoming these difficulties.
Modelling differential extinctions to understand big cat distribution on Indonesian islands
Authors: Wilkinson David M. , O'Regan Hannah J. 
Published: October 2003

ABSTRACTAims To model differential extinction rates for island populations of tigersPanthera tigrisand leopardsP. pardus.Location Indonesia.Methods We built VORTEX population models of tiger and leopard populations on an island the size of Bali (3632 km2), using data from the literature.Results The tiger populations were less extinction prone than the leopard populations. This was unexpected as tigers had the smaller population sizes and, as such, might be assumed to be more extinction prone. We identified several aspects of tiger breeding biology that explain the result.Main conclusions Sea level reconstructions suggest that both tiger and leopard would have been present in Java, Sumatra and Bali at the end of the last glacial. Our model provides a plausible mechanism based on population ecology to explain why these leopard populations were more extinction prone than the tiger populations. In addition it illustrates the potential utility of population ecology models in understanding historical patterns in biogeography.
Geomicrobiology of deep‐sea deposits: estimating community diversity from low‐temperature seafloor rocks and minerals
Authors: Rogers Daniel R. , Santelli Cara M. , Edwards Katrina J. 
Published: October 2003

ABSTRACTThe role of deep‐sea microbial communities in the weathering of hydrothermal vent deposits is assessed using mineralogical and molecular biological techniques. The phylogenetic diversity of varied deep‐sea bare rock habitats associated with the oceanic spreading centre at the Juan de Fuca Ridge was accessed using restriction fragment length polymorphism (RFLP) and rDNA sequencing. The mineralogical composition of the deposits used for phylogenetic analysis was determined by X‐ray diffraction in order to determine the proportion and composition of sulphide minerals, and to determine degree of alteration associated with each sample. RFLP analyses resulted in 15 unique patterns, or Operational Taxonomic Units (OTUs). Most environments examined were dominated by only one or two OTUs, which often comprised approximately 60% of the rDNA clones generated from that environment. Only one environment, the Mound, had a representative rDNA clone from every OTU identified in this study. For one other environment, ODP sediments, rDNA clones were all contained in a single OTU. The diversity of the microbial community is found to decrease with decreasing reactivity of the sulphide component in the samples and with increasing presence of alteration products. Phylogenetic analyses reveal that OTUs contain representatives of the epsilon‐, beta‐ and gamma‐subdivisions of the Proteobacteria. OTU1, which dominates clone libraries from every environment and is increasingly dominant with increasing rock alteration, is closely related to a group of chemolithoautotrophic iron‐oxidizing bacteria that have been recently isolated from the deep sea. The apparent abundance and widespread distribution within the samples examined of the putative iron‐oxidizing bacteria that may be represented by OTU1 suggests that this physiological group could play an important role in rock‐weathering and carbon fixation at the seafloor.
Biological and hydrogeological interactions affect the persistence of 17β‐estradiol in an agricultural watershed
Authors: Herman J. S. , Mills A. L. 
Published: October 2003

ABSTRACT17β‐estradiol (E2), one of the natural estrogen compounds, is an endocrine disruptor, and low levels in natural waters can impair the reproductive health of aquatic organisms. Its presence has been reported in animal faecal wastes and some aquatic habitats, including surface waters impacted by intense animal agriculture or sewage contamination. Little is known about its transport in hydrological systems or its persistence in water supplies. We routinely sampled stream and soil water over the growing season in an instrumented 1.2‐km2 agricultural watershed in central Virginia. E2 concentrations in stream water ranged from 0.01 to 0.12 ng mL−1; soil‐water values ranged from 0.03 to 0.18 ng mL−1. The highest concentrations were observed early in the growing season shortly after application of composted poultry litter to the cropped fields, and values decreased both with hydrological transport distance from the cropped field and over the course of the summer. Given the known application rate, E2 must be lost from the soil solution, and we explored biodegradation as a mechanism for this loss. A bacterial consortium cultured from the poultry compost biodegraded E2 in laboratory flasks amended with solutions of 1 : 1 acetate : glucose at concentrations ranging from 0.1 to 10 g L−1 dissolved organic carbon (DOC), spiked with 1.8 ng mL−1 E2, and incubated at different temperatures. A loss of 97–98% of the initial E2 occurred within 180 h in experiments at 22 °C and 28 °C with 1.0 or 0.1 g L−1 DOC amendments. Higher DOC concentrations and lower temperatures slowed the rates of reaction, suggesting that more readily available carbon inhibits use of the E2 by degrading micro‐organisms. The rapid rates of biodegradation in the laboratory incubations are inconsistent with the persistence of E2 in the watershed. This suggests that either the rates of biodegradation are reduced compared with the laboratory experiments or that E2 probably interacts with the components of the natural environment through complexation, sorption or abiotic transformation in the ageing process that leads to diminished bioavailability.
In situ growth of Gallionella biofilms and partitioning of lanthanides and actinides between biological material and ferric oxyhydroxides
Authors: Anderson C. R. , Pedersen K. 
Published: October 2003

ABSTRACT Gallionella ferruginea is an iron‐oxidizing chemolithotrophic micro‐organism that lives in low‐oxygen conditions (0.1–1.5 mg L−1 saturation). It produces a stalk structure from the concave side of the cell depending on population development, pH and redox conditions. After Gallionella oxidizes ferrous iron, bacteriogenic iron oxides (BIOS) precipitate on the stalk material and over time the stalks and/or the precipitated BIOS attenuate trace metals from surrounding groundwater. Gallionella ferruginea biofilms were cultured in situ in an artificial channel (2000 × 300 × 250 mm) using groundwater sourced from a borehole 297 m below sea level in the Äspö Hard Rock Laboratory in southern Sweden. The pH of the groundwater in the channels was always between 7.4 and 7.7 with oxygen saturation below 1.5 mg L−1 and Eh between 100 and 200 mV. Oxygen eventually declined to <0.3 mg L−1, terminating prolific biofilm growth. Biofilms formed within 2 weeks and were sampled every 2 weeks over 3 months. Cell number, stalk length and ferric iron concentration were measured for each sample and trace metal concentration was measured by inductively coupled plasma mass spectrometry. Results from well‐developed in situ biofilms suggest that Gallionella could concentrate metals at levels up to 1 × 103‐fold higher than found within the host rock and more than 1 × 106 times the levels found in the groundwater. These new experiments were used to support the results from the well‐developed biofilms and to relate biofilm development and population characteristics to metal attenuation. After 3 months, rare earth element (REE) plots indicated that BIOS can accumulate metals at levels up to 1 × 104‐fold higher than found in the groundwater and fractionate heavy rare earth elements over light rare earth elements. Generally the presence of the organic phase promotes the adsorption of all lanthanides and actinides that are not adsorbed by the inorganic phase. The iron oxides are directly correlated with stalk length (R = 0.96), indicating that rapid REE and actinide adsorption requires both iron oxides and a nucleating biological structure for the iron oxides.
Microbial diversity of a sulphide spire located in the Edmond deep‐sea hydrothermal vent field on the Central Indian Ridge
Authors: Hoek Joost , Banta Amy , Hubler Forrest , Reysenbach Anna‐Louise 
Published: October 2003

ABSTRACTA culture‐independent molecular phylogenetic survey was carried out for a bacterial and archaeal community of a mineralized crust coating a sulphide spire, which was collected from the Edmond vent field (23° S, 69° E, 3300 m depth) on the Central Indian Ridge. Small‐subunit rRNA genes (16S rDNA) were amplified from environmental DNA by PCR utilizing Bacteria‐specific, and Archaea‐specific 16S rDNA primers. PCR products were cloned and 26 bacterial and nine archaeal unique sequence types (phylotypes) were identified from 150 clones analysed by restriction fragment length polymorphism, representing eight and four distinct lineages, respectively. The majority (>90%) of the bacterial phylotypes group with the ɛ‐Proteobacteria and confirms the global prevalence of ɛ‐Proteobacteria in deep‐sea hydrothermal environments. Among the ɛ‐Proteobacteria, >40% of the phylotypes were closely related to the recently isolated deep‐sea vent thermophilic chemolithoautotrophic sulphur‐reducer, Nautilia lithotrophica. A single bacterial sequence was nearly identical (99% similarity) to the thermophilic hydrogen‐oxidizing Hydrogenobacter thermolithotrophum, and is the first report of Hydrogenobacter at deep‐sea hydrothermal vents. A majority (97%) of the archaeal phylotypes grouped with the ‘Deep‐sea Hydrothermal Vent Euryarchaeotal Group’, a phylogenetic lineage of uncultured Archaea that have only been reported from other deep‐sea hydrothermal vents on the Mid‐Atlantic Ridge, East Pacific Rise, Juan de Fuca Ridge, Isu–Ogasawara Arc, Okinawa Trough and the Manus Basin. A single sequence was closely related to the hyperthermophilic sulphur‐reducing Thermococcales frequently found in diverse deep‐sea vent environments. Scanning electron micrographs of the mineralized crust reveal abundant filamentous, rod and coccoidal forms encased in sulphur and sulphide mineral precipitate, suggesting that the thermophilic chemolithoautorophs and sulphide‐producing heterotrophs may influence the architecture and sulphur cycling of the sulphide spire.
Life tables and predation activity of Orius laevigatus and O. albidipennis at three constant temperatures
Authors: Cocuzza G. E. , De Clercq P. , Lizzio S. , Van de Veire M. , Tirry L. , Degheele D. , Vacante V. 
Published: October 2003

AbstractEffects of three constant temperatures (15, 25, and 35 °C) on development and reproduction of Orius laevigatus (Fieber) and O. albidipennis (Reuter) (Heteroptera: Anthocoridae) and on their predation activity against the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) were investigated in the laboratory. Small rooted plants of Spanish pepper (Capsicum annuum L. cv. ‘Creta’, long red) served as oviposition substrate and moisture source. Survival of eggs and nymphs of both species was high at 25 and 35 °C. At 15 °C, none of the eggs of O. albidipennis hatched and the number of nymphs completing the immature stage was extremely low. Developmental time of nymphs was not significantly different between species at 15 °C, but at 25 and 35 °C nymphs of O. laevigatus took significantly longer to develop than those of O. albidipennis. Females of O. albidipennis lived longer than those of O. laevigatus at 15 and 35 °C, but no differences were observed at 25 °C. Fecundity of O. albidipennis was greatly reduced at 15 °C, whereas a temperature of 35 °C was close to the upper reproduction threshold of O. laevigatus. Fecundity was highest at 25 °C for both species. At 15 °C, the intrinsic rate of increase (rm) reached a minimum for both species. For O. albidipennis, the rm‐value increased with temperature (0.121 at 25 °C and 0.202 at 35 °C), whereas for O. laevigatus it peaked at 25 °C (0.105) but decreased at 35 °C (0.051). At 15 and 25 °C, adults of O. laevigatus consumed more F. occidentalis adults during their total lifespan than those of O. albidipennis, but the latter showed a better predation activity at 35 °C; in all treatments, however, adults of O. laevigatus consumed more prey per day than did those of O. albidipennis. The performance of both anthocorids at the different temperatures is discussed in relation to their practical use in integrated pest control programmes.
Host selection by winged summer females of the aphid Sitobion avenae
Authors: Lushai G. , Sherratt T.N. , David O. , De Barro P.J. , Maclean N. 
Published: October 2003

AbstractA total of 55 parthenogenetic lineages of the grain aphid, Sitobion avenae F. were established from single clones collected from winter wheat (agricultural host) and cocksfoot (natural host) at various locations in southern Britain. RAPD‐PCR profiles indicated that these lineages consisted of at least 15 genetically distinct clones. Twenty winged individuals (alatae) of known weight were taken from each lineage and presented with a choice of wheat and cocksfoot hosts (with a total leaf area each of 2 cm2) held in petri dishes (laboratory experiments) and flowerpots (field experiments). In both experimental designs host preferences were determined by a ranking of a proportion of counts (limited to −1 →+1) of the progeny produced on each host after 5 days. Overall, alatae tended to prefer the agricultural host. However, alatae from individual clones found exclusively on wheat generally had a higher preference for wheat than alatae from individual clones found exclusively on cocksfoot. Wheat‐derived lineages (aphid genotypes that were collected on wheat but also present on cocksfoot) showed a significantly greater preference for the agricultural host than the cocksfoot‐derived lineages. Individuals from a wheat‐derived lineage had significantly higher observed and potential progeny production on wheat than they did on cocksfoot, while individuals from a cocksfoot‐derived lineage had significantly higher potential progeny but lower mean progeny weights on wheat. In a second stage, reciprocal host transfer experiments were carried out in the laboratory, i.e. lineages collected from the agricultural host were reared for several generations on the natural host and vice versa prior to being tested for host preference. The preference of the lineages for their host of origin significantly decreased in this second trial, reversing the overall preference trends, while there was little evidence for between‐lineage variation in this change in preference. In summary these results indicate weak genotypic but strong environmental influences on alate host preference in S. avenae. This host plant conditioning effect may serve to promote host‐based genetic structuring observed in southern British populations of S. avenae.
Costs and benefits of acclimation to elevated temperature in Trichogramma carverae
Authors: Scott Megan , Berrigan David , Hoffmann Ary A. 
Published: October 2003

AbstractThe consequences of acclimation for survival and other fitness components in the parasitoid wasp, Trichogramma carverae (Oatman and Pinto), were examined. Heat hardening adult wasps at 33 °C or 35 °C for one to two h increased survivorship at 40 °C. This benefit was apparent for several hours after heat‐hardening and occurred in both males and females. Heat hardening at 33 °C during development also resulted in significant increases in survivorship of adults after exposure to 40 °C. However, this developmental hardening reduced longevity of adult male and female wasps and also reduced parastism rate. This suggests costs and benefits of exposure to non‐lethal temperature increases. Acclimating wasps by rearing them under constant temperatures (14, 25 or 30 °C) influenced parasitism rates at these temperatures at the adult stage; only females reared at 14 °C parasitised eggs at 14 °C, while parasitism at 25 °C and 30 °C was not significantly influenced by rearing temperature. Acclimation may be useful for increasing the survival or fecundity of mass‐reared Trichogramma in inundative releases, but any benefits could be offset by fitness costs of the acclimation process.
Spatial and temporal distribution of endemic and released entomopathogenic nematode populations in turfgrass
Authors: Campbell J. F. , Orza G. , Yoder F. , Lewis E. , Gaugler R. 
Published: October 2003

AbstractEntomopathogenic nematodes (Rhabdita: Heterorhabditidae and Steinernematidae) have been effective as inundative biological control agents of scarab larvae (Coleoptera: Scarabaeidae) in turfgrass. Entomopathogenic nematodes also occur naturally in turfgrass and endemic or inoculated populations may be able to provide effective long‐term control. Variation in Heterorhabditis bacteriophora and Steinernema carpocapsae spatial and temporal distribution along transects placed at different turfgrass sites in central New Jersey, USA, was investigated. H. bacteriophora tended to be recovered from fewer sections in a transect than S. carpocapsae, but the two species, overall, did not differ in patchiness of distribution. In one transect with a H. bacteriophora population S. feltiae was also recovered, but the two populations seldom overlapped spatially. In transects with adequate scarab larvae density for analysis, H. bacteriophora density and Popillia japonica larvae density were inversely correlated. This suggests that endemic H. bacteriophora populations may suppress P. japonica populations. In one transect, an epizootic of H. bacteriophora in an undetermined host may have occurred. Edaphic factors were relatively uniform along transects and were, at most, weakly correlated with nematode recovery. Uniform inoculative releases of H. bacteriophora tended to return to patterns of distribution typical of endemic populations.
Different responses to temperature in three closely‐related sympatric cereal aphids
Authors: Turak E. , Talent R. , Sunnucks P. , Hales D. F. 
Published: October 2003

AbstractChromosomal races of the aphid Sitobion miscanthi (Takahashi), and a closely‐related species S. near fragariae (Aphididae: Macrosiphini) show seasonal differences in abundance in eastern Australia. We tested whether this was related to differences in temperature response, using controlled laboratory conditions. Intrinsic rate of increase, rm, mean relative growth rate (MRGR), and longevity were compared at different temperatures, and rates of increase were compared outdoors under ambient conditions. Using laboratory data, we simulated population growth, for comparison with outdoor populations. There were significant differences in responses to temperature regimes both in the laboratory and outdoors. Outdoor populations fell well short of predicted sizes. S. miscanthi (2n=18) showed evidence of adaptation to warmer conditions. In contrast, S. nr fragariae showed consistent evidence for adaptation to cooler conditions, and S. miscanthi2n=17 was approximately intermediate. These data indicate that temperature responses are important in the ecology, evolution and pest status of S. miscanthi clones and S. nr fragariae in Australia.