bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the diet of Leisler's bat (Nyctalus leisleri) in Ireland with some comparative analyses from England and Germany
Authors: Shiel C. B. , Duvergé P. L. , Smiddy P. , Fairley J. S. 
Published: February 2006

AbstractThe diet of Leisler's bat Nyctalus leisleri was investigated by analysis of droppings collected from six mainly pastoral sites in Ireland, two sites in England (one mainly pastoral, one arable predominating) and three in Germany (in forest), and comprised mainly medium‐sized and small insects caught in flight, many of which were probably from swarms. There was a major pastoral prey component, indicated mainly by Scathophaga stercoraria, Scarabaeoidea and associated Acari, at the Irish sites (estimated as 29–55%) and the English pastoral site (22%), but this was less significant elsewhere (1–12%). Insects with aquatic larvae (Ephemeroptera, Trichoptera, Chironomidae/Ceratopogonidae, Culicidae) often made up an important part of the diet (4–39%). Another distinct component, the Lepidoptera, Hemerobiidae, Chrysopidae and Ichneumonidae, which were all intercorrelated in the results, possibly indicates feeding near trees. This component was most important at the German (36–63%) and English arable (30%) locations, but of less significance at the English pastoral (11%) and Irish (2–19%, mean 6%) ones. The diets in Germany were otherwise diverse.
Sodium, net acid and ammonia fluxes in freshwater‐adapted European flounder (Platichthys flesus L.). Pharmacological inhibition and effects on gill ventilation volume
Authors: Clarke A. P. , Potts W. T. W. 
Published: February 2006

AbstractNet branchial sodium uptake, and net acid and ammonia excretion, together with gill ventilation volumes were measured in euryhaline European flounder Platichthys flesus, adapted to freshwater. External amiloride or acetazolamide (0.1 mmol l‐1) caused significant reductions (P < 0.05) in sodium uptake and net acid excretion, while 0.05 mmol l‐1 thiocyanate had no effect on any of the fluxes measured. Ethoxzolamide (0.1 mmol l‐1) however, caused significant reductions in all fluxes measured and also caused a 32% reduction in the volume of water exhaled by the gills. In this study, it appears that sodium uptake and net acid excretion are indirectly linked, probably by a proton pump arrangement which is thought to be a mechanism for sodium uptake in trout gills.
Isolated filament potentials and branchial ion fluxes in the European flounder (Platichthys flesus L.). Evidence for proton pump mediated sodium uptake
Authors: Clarke A. P. , Potts W. T. W. 
Published: February 2006

AbstractBranchial sodium uptake, and net proton equivalent and ammonia excretion, together with isolated filament potentials were measured in euryhaline European flounder Platichthys flesus, adapted to freshwater. External benzamil (0.05 mmol l‐1), a specific inhibitor of sodium conductive channels, caused significant reductions (P < 0.05) in sodium uptake and a marked decline in net proton equivalent excretion. In contrast, 0.05 mmol l‐1 external 5‐(N,N‐dimethyl)‐amiloride, a specific inhibitor of the Na+/H+ antiport, had no effect on any of the fluxes measured. The effect of vanadate, an inhibitor of H+‐ATPases, was examined at two concentrations, 0.1 and 0.5 mmol l‐1, and both caused significant reductions (P < 0.05) in sodium uptake and net proton equivalent excretion. Mean resting isolated gill filament potentials in freshwater‐adapted P. flesus were found to be −23.8 ± 1.1 mV (inside negative) and became less negative in the presence of amiloride, an inhibitor of sodium transport. Using microelectrodes it was possible to measure two potentials in the filament: an apical potential and a transepithelial potential. The transepithelial potential was similar to that measured in vivo, while the apical potential, may be generated by the pavement epithelial cells. In this study, it appears that sodium uptake and net proton equivalent excretion are not strictly coupled but are indirectly linked probably by a proton pump arrangement, which is thought to be a mechanism for sodium uptake in trout gills. A possible role of the apical potential is discussed.
Do emerging pipistrelle bats lose control of their timing due to ‘crowd pressure’?
Authors: Speakman J. R. , Tallach N. 
Published: February 2006

AbstractWhen bats emerge from colonies to feed and drink their emergence patterns deviate systematically from those expected at random (Kunz, 1974; Swift, 1980; Bullock et al., 1987; Brigham & Fenton, 1986). In particular, many bats appear to group together as they emerge, and form into ‘clusters’ or ‘outbursts’ (but see McAney & Fairley, 1988; Kunz & Anthony, 1995 for exceptions). The function of this clustering behaviour has been the topic of recent debate, with some authors favouring the hypothesis that the behaviour is an artefact of large numbers of animals moving through a restricted space (Kalcounis & Brigham, 1994) and others suggesting the behaviour has a more significant biological function such as protection from predation (Leen & Novick, 1977; Speakman, Stone & Kerslake, 1995) or information transfer (Wilkinson, 1992).
Summer foods of the Andean hog‐nosed skunk (Conepatus chinga) in Patagonia
Authors: Travaini A. , Delibes M. , Ceballos O. 
Published: February 2006

AbstractThe Andean hog‐nosed skunk Conepatus chinga inhabits South America from Bolivia in the north to as far south as Neuquén province in Argentina (Redford & Eisenberg, 1992). In spite of its wide distribution and its value as a furbearer in Argentina (Fujita & Calvo, 1982), little is known about Andean hog‐nosed skunk ecology, including its foods. It seems to forage solitarily during the night in open savannas and in arid and shrubby areas (Cabrera & Yepes, 1960; Mares et al., 1996), capturing arthropods (mainly beetles and arachnids) and occasionally small mammals and preying on eggs and fledgling birds (Cabrera & Yepes, 1960; Redford & Eisenberg, 1992; Mares et al., 1996). Here we present the first quantitative study on the diet of this species, based on the analysis of faeces collected during the summer season in two localities in Argentinean Patagonia.
Fraser's dolphin (Lagenodelphis hosei) stranded in South Uist: first record in U.K. waters
Authors: Bones M. , Neill B. , Reid B. 
Published: February 2006

AbstractOn 3 September 1996, B. Neill, investigating the peculiar behaviour of three ravens, found them disputing over a freshly dead dolphin stranded on the shore at Bornish, South Uist, Western Isles, Scotland (National Grid ref: NF 721 300). Neither he nor M. Bones, who collected the skeleton, could immediately identify the dolphin, despite having seen most of the species recorded around the Western Isles, although we suggested that it might be an Atlantic white‐sided dolphin Lagenorhynchus acutus with an aberrant colour pattern.
The difficulty of estimating population densities of nocturnal forest mammals from transect counts of animals
Authors: Duckworth J. W. 
Published: February 2006

AbstractMany nocturnal small‐ to medium‐sized forest mammals can be surveyed only by directly sighting or hearing each individual. This is particularly so in tropical regions. Signs (footprints, dung scratch‐marks, etc.) are often not identifiable to species (similar species frequently occur together); villagers' identifications are rarely clear enough for research purposes, and the provenance of specimens in markets can rarely be established to satisfactory precision. Assessments of animal status from brief surveys are becoming increasingly important for many conservation purposes. A repeatable methodology for field assessment of the status of nocturnal mammals is needed to allow comparisons, particularly between sites.
Cached fungi in non‐native conifer forests and their importance for red squirrels (Sciurus vulgaris L.)
Authors: Lurz P. W. W. , South A. B. 
Published: February 2006

AbstractThe caching of fungi by red squirrels Sciurus vulgaris was investigated in commercial conifer plantations by walking transects in Kielder Forest, Cumbria and Wauchope Forest, Scotland. In 11 transects, a total of 58 fungal fruiting bodies were observed on branches in trees, consisting of four different species (49 Russula ochroleuca, seven R. metica, one R. vesca, one Colybia maculata). Fungal stores were found to be short lived and most fruiting bodies cached were gone after 2 weeks. Based on the survey findings we estimate that within an average red squirrel home range there would be a minimum of 42 cached fruiting bodies, constituting a food store of approx. 525–714 kJ.
The denning behaviour of feral ferrets (Mustela furo) in a pastoral habitat, South Island, New Zealand
Authors: Ragg J. R. 
Published: February 2006

AbstractThis paper describes the denning behaviour of 24 feral ferrets Mustela furo on farmland, East Otago, South Island, New Zealand. One hundred and ninety seven dens were located and radio‐collared ferrets were found to share dens simultaneously with other ferrets on 7.4% of 706 radio‐tracking events and used dens that had been previously used by other ferrets (sequential den sharing) on 44.3% of occasions. In this particular study, ferrets were exhibiting a higher degree of sociality than has been recorded in other solitary mustelid species and therefore may not be adhering to the model of intrasexual territoriality thought to apply to other mustelid species. Den sharing may be a mechanism by which bovine tuberculosis Mycobacterium bovis is transmitted within ferret populations. Over 80% of the sequential den sharing occurred within 14 days, well within the survival span of M. bovis bacilli. Denning of infected ferrets in haybarns may pose a risk of transmission of M. bovis to livestock from hay.
Habitat use and diet of the American mink (Mustela vison) in Argentinian Patagonia
Authors: Previtali A. , Cassini M. H. , Macdonald D. W. 
Published: February 2006

AbstractPopularity as a fur‐bearing species led to the American mink Mustela vison being transported far beyond its native range in North America (Dunstone, 1993). In many places the species was bred in fur farms, from which there were inevitably escapes, and in some areas it was deliberately released in large numbers with the intention of establishing harvestable populations. Both routes led to the widespread establishment of feral populations of this versatile semi‐aquatic mustelid. Invariably, close scrutiny of the impact of feral American mink on native fauna has led at least to concern, and increasingly to proof, that they are inimical to the conservation of native species. Evidence of the impact of the American mink on native species falls into two categories. First, American mink may reduce significantly, and locally exterminate, certain vertebrate prey (Macdonald et al., in press). Second, as versatile and seemingly aggressive competitors they may alter the competitive balance within the local guild of semi‐aquatic predators, even ousting native mustelids.
Sexual dimorphism in neonate and adult snakes
Authors: King R. B. , Bittner T D. , Queral‐Regil A. , Cline J. H. 
Published: February 2006

AbstractSex differences in body size and head dimensions are widespread in adult snakes, but because data are scarce for neonates, it is unclear whether differences are present from birth or arise post‐natally. Here we analyse patterns of sexual dimorphism in neonates and adults of four species of natricine snakes, Nerodia sipedon, Storeria dekayi, Thamnophis radix, and T. sirtalis. Two measures of body size (snout–vent length, mass), four measures of head morphology (head length, head width, jaw length, and interocular distance), and tail length were obtained from wild‐caught adults and from offspring born to wild‐caught females. Among neonates, significant sexual dimorphism was found in body size for S. dekayi and T. sirtalis, in head dimensions for S. dekayi, T. radix, and T. sirtalis, and in tail length for all four species. Among adults, significant sexual dimorphism was found in body size, head dimensions, and tail length for all four species. The degree of sexual dimorphism in body size among adults greatly exceeded that among neonates. In contrast, the degree of sexual dimorphism in head dimensions was similar between neonates and adults. The presence of significant sexual dimorphism among neonates suggests that hypotheses regarding the evolutionary significance of sexual dimorphism in snakes should consider newborns as well as adults.
What, if anything, is a cursor? Categories versus continua for determining locomotor habit in mammals and dinosaurs
Authors: Carrano M. T. 
Published: February 2006

AbstractTraditional categories of locomotor habit in mammals are largely based on variables that are continuous in nature, making intermediate forms difficult to evaluate quantitatively. Interpretations of these categories have varied greatly among authors, mainly owing to the inconsistent meanings ascribed to these essentially morphological variables. As a result, it is not clear whether these categories reflect any true locomotor influence, or if they can be applied in any form to non‐mammalian taxa. In order to rectify these two difficulties, locomotor categories are rejected here in favour of a multivariate continuum. By basing this continuum on morphological variables that fulfil predictions of limb design under biomechanical theory, it can be tied to limb mechanics and applied to both extant and extinct animals alike. A series of such measurements were taken from a large sample of mammal and dinosaur hindlimb bones, and subjected to statistical testing. Patterns of variation in dinosaurs are similar to those seen in mammals, ranging between extremes traditionally designated as ‘cursorial’ and ‘graviportal’. An evaluation of dinosaur locomotor evolution in light of this continuum suggests that dinosaurs originated as small cursors, but that most lineages acquired a more mid‐grade locomotor habit. Large taxa (sauropods, armoured ornithischians) were essentially graviportal, while smaller forms tended towards cursoriality; only coelurosaur theropods developed cursoriality at large body sizes. The discrepancy between large, graviportal herbivores and large, mid‐grade to cursorial carnivores in Mesozoic communities argues against pursuit predation as a major influence in dinosaur locomotor evolution.
Genetic similarity between Akodon olivaceus and Akodon xanthorhinus (Rodentia: Muridae) in Argentina
Authors: Pearson Oliver P. , Smith Margaret F. 
Published: February 2006

AbstractOn an East–West transect in northern Patagonia, the steppe‐inhabiting mouse Akodon (or Abrothrix) xanthorhinus meets the forest‐inhabiting Akodon (Abrothrix) olivaceus on the eastern side of the Andes where steppe meets forest. In a contact zone of about 30 km, the mice are morphologically intermediate. Nuclear (allozyme) and mitochondrial DNA analyses confirm that the genetic difference between eastern, western, and intermediate populations is not much greater than would be expected within individuals from a single population. We conclude that xanthorhinus and olivaceus should be united under the species name olivaceus.
Dynamics of a clinal hybrid zone and a comparison with island hybrid zones of flycatchers (Ficedula hypoleuca and F. albicollis)
Authors: Sætre G.‐P. , Král K. , Bures S. , Ims R. A. 
Published: February 2006

AbstractBreeding data for pied flycatchers Ficedula hypoleuca and collared flycatchers F. albicollis, from 47 localities in the Czech Republic and Slovakia, were analysed. We show that co‐existence and hybridization were mainly restricted to a rather narrow, latitudinal cline. The distribution of the two flycatchers coincides with topography and habitat, collared flycatchers dominating in warmer habitats than pied flycatchers. Maintained co‐existence within the same locality was the exception rather than the rule and most matings occurred in allopatry. In sympatry hybridization occurred at a frequency that was much lower than expected from random mating. Hybrids had low hatching success but some hybrids were apparently fertile. Shortage of conspecific mates may explain why individual birds engage in mixed species pairs. The proportion of pied flycatchers that was involved in mixed pairs was high and increased with decreasing relative frequencies of pied flycatchers in the population. The proportion of collared flycatchers involved in mixed pairs was low, reflecting the higher relative frequency of this species in most mixed populations. Comparisons suggest that fewer hybrids are breeding in the Central European, clinal hybrid zone than in the isolated hybrid zones of the Baltic Isles. Moreover, hybrid fertility was apparently higher in the island zones than in the clinal zone. We suggest that more extensive introgression in the isolated island populations has resulted in an increase in hybrid fitness by an accumulation of fertile individuals of mixed ancestry (i.e. F2, F3 … Fn‐hybrids) acting as bridges for gene exchange. Differences in the dynamics of the two classes of hybrid zones, especially in pattern of gene flow, may explain these differences in frequency and fertility of hybrids.
Inter‐annual differences in the age‐related prevalences of Babesia and Trypanosoma parasites of European badgers (Meles meles)
Authors: Macdonald D. W. , Anwar M. , Newman C. , Woodroffe R. , Johnson P. J. 
Published: February 2006

AbstractA total of 263 individual badgers Meles meles provided 718 blood samples which were screened for parasites. This revealed that 77.2% of individuals tested positive for Babesia missirolii at least once over 3 years, whereas 7.7% did so for Trypanosoma pestanai. However, the prevalence was highest in younger age classes, except in 1990 when it was high in most categories. There was some evidence that following a positive test for Babesia badgers were more likely to be caught again in subsequent years when compared to individuals testing negative. For Trypanosoma, although prevalence decreased from a peak of 29.2% from June onwards in 1990, we found no significant corollaries of infection. These results are discussed in the light of inter‐annual variation in weather and other factors.
Bracketing the extremes: courtship behaviour of the smallest‐ and largest‐bodied species in the salamander genusDesmognathus(Plethodontidae: Desmognathinae)
Authors: Verrell Paul 
Published: February 2006

AbstractWith both a ‘manageable’ number of taxa and moderate levels of behavioural diversity, plethodontid salamanders of the North American subfamily Desmognathinae offer exciting opportunities for a phyloethological study of courtship. In moving toward this goal, the present paper reports courtship descriptions for two taxa with very different biologies: the pygmy salamanderDesmognathus wrightiand the blackbelly salamanderD. quadramaculatus. Despite similarities in behaviour patterns used to accomplish indirect sperm transfer by means of the deposition of spermatophores on the substrate (tail‐straddle walk), these two taxa greatly differ in the ways by which males stimulate, or ‘persuade’, females to mate. MaleD. wrightibite and seize their partners in order to provide them with tactile and chemical stimuli. In contrast, maleD. quadramaculatusprovide these same stimuli, but by head rubbing and snapping. I end with a comparative survey of courtship in the Desmognathinae, and a first attempt to interpret behavioural evolution in the subfamily using a phyloethological analysis.
Sexual size and shape dimorphism in two species of newts, Triturus cristatus and T. vulgaris (Caudata: Salamandridae)
Authors: Malmgren Jan C. , Thollesson Mikael 
Published: February 2006

AbstractMorphometric data from Fennoscandian populations of the crested newt Triturus cristatus and the smooth newt Triturus vulgaris were analysed for the presence of sexual size and shape dimorphism. The data sets included nine body‐related and nine head‐related measurements and were examined with univariate, bivariate and multivariate methods. Sexual dimorphism was demonstrated in both species. The separation of specimens was highly related to sex. Although the expression of sexual dimorphism differed between the two species, some patterns were shared. These are discussed in terms of evolution of intersexual dimorphism according to models of ecology, fecundity and sexual selection. In multivariate analyses, sexual dimorphism was restricted to body‐related variables such as standard length and distance of extremities (with high values for females), contrasting against cloaca and limb‐related characters (with high values for males). In both species, the ‘distance of extremities’ measure (i.e. trunk length) was one of the strongest sexually dimorphic traits. No evidence of sexual dimorphism in head morphology was found. The results are interpreted as primarily concordant with theories on fecundity selection. For example, it has been suggested that females with larger trunk volumes increase their reproductive capacity. The fact that males had longer extremities, in relation to other characters measured, could be attributed to sexual selection. Long limbs in male newts may be beneficial for courtship performance. Since head‐related characters did not show any patterns of sexual dimorphism, no evidence was found to suggest that male and female crested and smooth newts have adapted to different feeding strategies.
Genetic structure among populations of Potamonautes perlatus (Decapoda: Potamonautidae) from the Olifants River system in the Western Cape, South Africa
Authors: Daniels Savel R. , Stewart Barbara A. , Gibbons Mark J. 
Published: February 2006

AbstractPopulations of Potamonautes perlatus were sampled at various points along the Olifants Rivers (220 km), in the Western Cape to examine the degree of genetic variation. Allozyme electrophoresis revealed a near fixed allelic difference at one locus and extensive differentiation at another locus between populations from the upper and lower reaches of the Olifants River system. Limited hybridization in the region of population sympatry was observed. The narrow hybrid zone and the low occurrence of hybrids suggest selection against hybrids. These results provide evidence for two genetically distinct freshwater crab populations. We concluded that the genetic divergence between the two population groups represents a species boundary between the two populations.