共查询到20条相似文献,搜索用时 15 毫秒
1.
Luigi Remonti Claudio Prigioni Alessandro Balestrieri Silvia Sgrosso Giuseppe Priore 《Mammalian Biology》2008,73(4):293-302
Diet composition of otters (Lutra lutra) was investigated in 2001 by spraints analysis (N=1323) on five rivers of southern Italy, with the aim of assessing the influence of fish availability, elevation and discharge on the consumption of food resources alternative to fish. Data were expressed as per cent frequency of occurrence (%FO) and per cent volume (%V). The study confirmed the great feeding adaptability of the otter that, in rivers partially interconnected and flowing on a small area, showed a strong fish eating habit in some rivers (Sinni and Mercure-Lao) and a diet mainly constituted by alternative resources in other ones (amphibians in the rivers Cogliandrino and Frido, crustaceans in the River Battendiero). Fish consumption for the five rivers was significantly correlated with fish biomass and with mean summer discharge, while it was inversely correlated with the mean altitude of the five rivers. The lack of a clear seasonality in the consumption of food sources alternative to fish together with the correlation between fish use and fish biomass for each river indicated fish availability as the main factor affecting otter relying to non-fish preys. Otter diet seemed influenced by the characteristics of river habitats (altitude, discharge and consequently fish biomass) more than by summer drought, typical of Mediterranean regions. The %FO and the %V allowed to drawn a similar picture of otter diet. Nonetheless the %V was useful for better illustrating diet variation among the different rivers and we argue that it could be useful in habitats where the otter feeds on preys with different proportions of indigestible remains. 相似文献
2.
In this study, we used genetic-based approaches to estimate population size and structure of Eurasian otter along the Drava River in Hungary, and compared these results to traditional survey-based methods. The relative spraint density of otter was estimated based on the number of fresh (Df) and total number (Dt) of spraints collected on standard routes over a 2-year period. Nine microsatellite loci were screened, generating 17 individual otter genotypes composed of 45 different alleles. The expected heterozygosity ranged from 0.53 to 0.89 and observed heterozygosity from 0.25 to 0.92. The mean density (Dg) estimated over six different sites was 0.17 individuals per km of shoreline. A close correlation was found between the number of genotypes and spraint counts along a standard route (fresh spraints: rP=0.85, P<0.01; total spraints rP=0.76, P<0.05). All genotypes found within the 50 km-long study area were closely related (Dm ranged between 0.08 and 0.21). 相似文献
3.
4.
Ann‐Christin Honnen Britt Petersen Leena Kaßler Morten Elmeros Anna Roos Robert S. Sommer Frank E. Zachos 《Journal of Zoological Systematics and Evolutionary Research》2011,49(2):169-175
We analysed 229 Eurasian otters from eastern and north‐western Germany, Denmark and southern Sweden based on sequences of the mtDNA control region and genotypes at 12 polymorphic nuclear microsatellite loci. The main focus of the study lay on the north‐west German otters from Schleswig‐Holstein, which represent a newly established and expanding population recolonizing a formerly inhabited region, thereby closing the distributional gap between the large eastern population and the long‐isolated and genetically depleted Danish population. As found before in this species, mtDNA variability was very low but we identified a hitherto unknown haplotype in Sweden. Expected heterozygosities were between 0.46 and 0.69 and thus within the range known from the literature. There were only weak signs of a founder effect in the Schleswig‐Holstein otters with respect to allelic diversity (but not heterozygosity). Nevertheless, there was a statistically significant bottleneck signal based on deviations from mutation‐drift equilibrium in Schleswig‐Holstein. All statistical approaches (amova s, factorial correspondence analysis, assignment tests and Bayesian structure analysis) unequivocally showed that north‐western Germany has so far been predominantly recolonized by otters of east German origin, but we also found evidence of admixture through immigration from Denmark. Both the Danish and the north‐west German otter population will benefit from further exchange in the wake of the ongoing range expansion. 相似文献
5.
We developed a new PCR/RFLP system targeted to amplify and cut a segment of the ZFX/ZFY gene in non-invasive otter (Lutra lutra) samples. This assay produced one sex-specific fragment in females (XX genotypes) and two fragments in males (XY genotypes),
and is intrinsically more reliable than alternative systems (e.g., SRY genes) that are based on the amplification of a single
Y-linked fragment. The new primer pair correctly identified the sex of 23 DNA extracted from sexed otter tissues. This procedure
was used to sex unknown DNA extracted from otter scats. A multi-tube approach led to identify the sex of 72/91 (79%) samples,
using a minimum of two PCR replicates. This procedure is currently used in non-invasive genetic monitoring of Italian otter
populations. 相似文献
6.
Long-term studies were carried out in central Finland between 1985 and 2003 to examine the temporal and spatial variation in the density of otter populations. Snow tracking was used to estimate the total population and the number of litters in the study area. In total 52 otters, including 16 cubs in 11 litters, lived in the study area (1,650 km2) in 2002–2003. The otter population clearly increased during the study period. The increase in density of the otter population was sigmoid, indicating that the population had reached the local carrying capacity. The density of the population was 0.12 individuals per river ha in 1985 and 0.29 individuals per river ha in 2002. The number of cubs per litter decreased when the density of the population increased. Density-dependent offspring production, together with the auto-correlation function of growth rate, indicates intraspecific competition in otter populations. Otters in a few river systems produced most of the cubs, creating several small source populations in the entire study area. Otters in secondary (sink) habitats had a low reproduction rate. Most otters lived in river systems with large lake surfaces. The number or area of lakes within the river system correlated positively with the total number of otters, litters and cubs in the river system. The six river systems (out of 16) with the largest water area of lakes produced 81.2% of all cubs born in the study area. However, the population growth rate per river hectare or per river kilometre was equal in all kinds of river systems. Thus, among local otter populations in central Finland, a source–sink system between different habitats seems to be prevalent. 相似文献
7.
DNA “fingerprinting” and the genetic management of a captive chimpanzee population (Pan troglodytes)
DNA fingerprinting probes are cloned sequences which simultaneously detect a large number of similar hypervariable loci in the target DNA. The resulting highly polymorphic pattern visualized on an autoradiograph allows resolution of questions concerning individual identification and parentage. M13 bacteriophage has been used as a DNA fingerprinting probe for paternity ascertainment among captive chimpanzees housed in multi-male groups as part of the National Chimpanzee Breeding and Research Program. In 31 cases of unknown paternity where DNA samples for mother, offspring, and all potential sires were available, DNA fingerprinting with M13 resulted in the unambiguous assignment of paternity for all 31 infants. Knowledge of pedigrees among the captive-born animals is used to address several issues important in the genetic management of captive breeding colonies, including estimation of effective population size and of the rate of decline in genetic variability, variance in male and female reproduction, and the effect of social dominance on male reproductive success. Our analysis demonstrates the beneficial effects of genetic management by comparing the managed dedicated cohort to the Bastrop colony as a whole. 相似文献
8.
Mingli Zhang Peter W. Fritsch Boni C. Cruz 《Molecular phylogenetics and evolution》2009,50(3):547-559
Phylogenetic relationships of 48 species of Caragana (Fabaceae: tribe Hedysareae) and one representative each of Astragalus, Calophaca, Halimodendron, and Hedysarum are estimated from DNA sequences of the rbcL gene, trnS–trnG intron and spacer, and ITS region. At least one representative of all five sections and 12 series within Caragana are included. Analyses yielded strongly supported clades corresponding to sections Caragana, Bracteolatae, and Frutescentes. The species of section Jubatae are distributed among three strongly supported clades, i.e., one with the species of section Bracteolatae, another with two species of section Spinosae, and a third as sister to section Frutescentes. All but the last of these six clades are corroborated by at least one unambiguously traced morphological character. The placement of the other four species of section Spinosae are not well supported and lack unambiguous morphological synapomorphies, and the samples of Calophaca and Halimodendron nest within Caragana with weak support. 相似文献
9.
Michaela Zeiner Mihaly Ovari Gyula Zaray Ilse Steffan 《Journal of trace elements in medicine and biology》2006,20(4):240-244
Reference concentrations of metals are the basis for risk assessment studies and for estimation of type and magnitude of environmental and occupational exposure. Urine is often used as a specimen for monitoring studies, as it plays an important role in the elimination of various substances from the body and in addition it can be collected easily. Therefore, the urinary levels of seven trace elements (Al, Co, Cr, Mo, Nb, Ni, Ti) were determined by atomic spectrometric methods (ICP-MS and GFAAS) in 100 urine samples of the Viennese population. The obtained creatinine adjusted concentrations (medians) are in μg/g 6.1, 1.5, 1.1, 46.2, 0.4, 0.1, and 8.0 for Al, Co, Cr, Mo, Nb, Ni, and Ti, respectively. 相似文献
10.
The phylogeny of the genus Cynanchum s. str. is studied using cpDNA spacers and ITS. Morphological, anatomical and latex triterpenoid data are interpreted in light of the molecular results, and discrepancies are discussed. Vegetative characters are better indicators of relationship than floral characters, especially corona characters. The monophyly of all Malagasy species and, nested within the latter, of all stem-succulent taxa is ascertained and the genera Folotsia, Karimbolea, Platykeleba and Sarcostemma are subsumed under Cynanchum. One African species, C. galgalense, is excluded from Cynanchum. 相似文献
11.
12.
With the world currently facing a global amphibian extinction crisis, the development of techniques to help meet the needs of conservation managers and researchers studying the reproductive biology of amphibians is needed. Here, we developed enzyme immunoassays to measure estrone, testosterone, and progesterone hormone metabolites in the urine of Litoria raniformis, the southern bell frog. Concentrations of urinary estrone, testosterone, and progesterone increased during the breeding season for females (P < 0.05). Concentrations of urinary testosterone and progesterone increased for males during the breeding season compared with that for months where no reproductive behaviors were observed (P < 0.05). Furthermore, urinary estrone concentrations proved to be a reliable sexing tool for adult frogs, with no overlap between the sexes in 98% of cases, regardless of season. There was no difference in estrone (P = 0.204) or testosterone (P = 0.485) metabolite concentrations between samples taken immediately upon capture and those taken 12 to 24 h later from the same individual. Progesterone metabolite concentrations were lower on Day 2 than upon collection (P = 0.004). This is the first study to show that urinary hormone analysis can be a useful technique for reproductive monitoring in an amphibian. Additionally, hormone metabolite measures offer promise as sex identification tools for monomorphic species and for those whose secondary sex characteristics are visible only during the breeding season. 相似文献
13.
14.
We used 766 bp of DNA sequence data from the mitochondrial cytochrome oxidase I gene to reconstruct a phylogeny for 39 of 43 Ips species, many of which are economically important bark beetles. The phylogeny was reconstructed using equally weighted and weighted parsimony. In both analyses, peripheral clades were well supported while internal clades were poorly supported. Phylogenetic analysis of translated amino acids produced a poorly resolved tree that was discordant with trees reconstructed with nucleotide sequence data. Two main conclusions are drawn about the monophyly of Ips and traditional systematic groups within Ips. First, Ips is monophyletic only when I. mannsfeldi, I. nobilis, and the concinnus and latidens species groups are excluded. The latidens group, I. mannsfeldi, and I. nobilis form a monophyletic group with 3 Orthotomicus species, while the concinnus group has a more basal position. Second, the majority of the species groups in the current classification for Ips are not monophyletic. European Ips species do not form a monophyletic group, contrary to common usage, and are dispersed on the phylogenetic tree among North American species. These results indicate that a formal systematic revision of Ips is needed. 相似文献
15.
16.
Peter M. Letcher Carlos G. Vlez María Eugenia Barrantes Martha J. Powell Perry F. Churchill William S. Wakefield 《Mycological Research》2008,112(7):759-782
The Rhizophydiales is the most recently circumscribed order in the Chytridiomycota. Past studies focused on soil chytrids from North America and Australia to determine the range of diversity within this clade of chytrids and established three families (Rhizophydiaceae, Terramycetaceae, and Kappamycetaceae) in the new order. Although Rhizophydiales contains seemingly simple chytrids morphologically, analyses of ribosomal gene sequences and zoospore characters have demonstrated unexpected genetic and ultrastructural diversity, highlighting the need for broader habitat and geographic sampling to reveal the actual diversity within this new order. To enlarge our sampling, in this study we investigated 38 newly cultured chytrids collected from aquatic habitats in Argentina, a territory under-explored for chytrid diversity. From analyses of thallus morphology, zoospore ultrastructure, and 28S and ITS1–5.8S–ITS2 ribosomal gene sequences, we expand the concept of Rhizophydiales, describing seven new families (Alphamycetaceae, Angulomycetaceae, Aquamycetaceae, Globomycetaceae, Gorgonomycetaceae, Pateramycetaceae, and Protrudomycetaceae) and eight new genera (Alphamyces, Angulomyces, Aquamyces, Globomyces, Urceomyces, Gorgonomyces, Pateramyces, and Protrudomyces). Results of this study underscore that even more extensive sampling from varied habitats and geographies is needed to adequately ascertain the diversity of chytrids in the Rhizophydiales. 相似文献
17.
18.
Using a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method to obtain genotypes for the diploid pathogenic yeast, Candidaalbicans, we analysed 204 C. albicans isolates from three populations of the Duke University community: two from clinical sources [one from patients infected with human immunodeficiency virus (HIV) and the other from patients without HIV infection], and the third from healthy student volunteers. The results indicated: (i) extensive evidence for clonality within and between populations of C. albicans; and (ii) greater genotypic and gene diversities in the nonclinical population than those derived from clinical specimens, regardless of HIV status. The two clinical populations were genetically more similar to each other than either was to the population consisting of isolates from healthy people. Within each population sample there was a general lack of heterozygotes, and random associations of alleles within and between loci were found in less than 50% of the loci or pairs of loci. These findings were consistent between the two sets of samples analysed: those including all isolates and those including only clone-corrected isolates. Possible mechanisms are presented to explain the observed patterns of genetic variation within and between C. albicans populations. 相似文献
19.
In the intestine of two wolves (Canis lupus) from Germany 33 adult tapeworms were found. The cestodes were determined as Taenia krabbei Moniez, 1879 (Syn. T. cervi Christiansen, 1931). Adult parasites were compared with cysticerci from thigh muscles of roe deer (Capreolus capreolus) as well as cysticerci from cardiac muscles of sheep (Ovis ammon). It is postulated that T. krabbei from wolf and roe deer is a valid and distinct species which uses Cervidae as original intermediate hosts. T. krabbei is highly similar in all morphological criteria to T. ovis. However, the life history of T. ovis includes Bovidae, preferably sheep as intermediate hosts. 相似文献
20.
“How can life be tiresome so long as there is still a new rhizopod undescribed?”Joseph Leidy 相似文献