Search results for "natural population"
showing 10 items of 20 documents
Linkage disequilibria between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura
2001
The association between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura from Calvia (Balearic Islands, Spain) was studied in order to search for linkage disequilibria, in an attempt to explain the populational dynamics of the mtDNA haplotypes of this species in nature. The presence of Wolbachia was not detected. Two main haplotypes (I and II) were found, as well as a series of less common ones. The Tajima D-test seemed to indicate some kind of seasonal population bottleneck. An analysis of linkage disequilibrium and factorial analysis of correspondences detected an association between haplotype I and the J(ST) inversion and haplotype II and the…
Carry-over effects of conditions at the wintering grounds on breeding plumage signals in a migratory bird : roles of phenotypic plasticity and select…
2016
To understand the consequences of ever-changing environment on the dynamics of phenotypic traits, distinguishing between selection processes and individual plasticity is crucial. We examined individual consistency/plasticity in several male secondary sexual traits expressed during the breeding season (white wing and forehead patch size, UV reflectance of white wing patch and dorsal melanin coloration) in a migratory pied flycatcher (Ficedula hypoleuca) population over an 11-year period. Furthermore, we studied carry-over effects of three environmental variables (NAO, a climatic index; NDVI, a vegetation index; and rainfall) at the wintering grounds (during prebreeding moult) on the expressi…
A trade-off between sexual signalling and immune function in a natural population of the drumming wolf spider Hygrolycosa rubrofasciata.
2005
The field of ecological immunology is ultimately seeking to address the question ‘Why is there variation in immune function?’ Here, we provide experimental evidence that costs of ubiquitous sexual signals are a significant source of variation in immune function. In the mating season, males of the wolf spider Hygrolycosa rubrofasciata drum against dry leaves while wandering around the habitat searching for receptive females. According to a previous study, the male metabolic rate during the drumming increases 22-fold compared to the resting metabolic rate. In the present study, we examined whether investment in costly courtship drumming decreases male immune function in a wild population of H…
Mitochondrial DNA haplotype frequencies in natural and experimental populations of Drosophila subobscura.
1998
Abstract The evolution of Drosophila subobscura mitochondrial DNA has been studied in experimental populations, founded with flies from a natural population from Esporles (Majorca, Balearic Islands, Spain). This population, like other European ones, is characterized by the presence of two very common (>96%) mitochondrial haplotypes (called I and II) and rare and endemic haplotypes that appear at very low frequencies. There is no statistical evidence of positive Darwinian selection acting on the mitochondrial DNA variants according to Tajima's neutrality test. Two experimental populations, with one replicate each, were established with flies having a heterogeneous nuclear genetic back…
Phenotypic variation in infectivity of Diplostomum spathaceum cercariae within a population.
2007
The present study examined phenotypic variation in infectivity of Diplostomum spathaceum (Trematoda) cercariae within a natural population. Twelve infected Lymnaea stagnalis were collected from the field, and the infectivity of cercariae from individual snails was assessed under constant laboratory conditions. At a water temperature of 16.3 C, the mean infectivity of cercariae from the snails varied between 55.5% and 87.5%. Depending on the source of variation, this may have important ecological and evolutionary implications for both natural parasite populations and those occurring in aquaculture.
Seasonal cardenolide production and Dop5βr gene expression in natural populations of Digitalis obscura
2004
Productivity variations and seasonal fluctuations of cardenolides have been studied in 10 natural populations of Digitalis obscura distributed in three bioclimatic belts. Main cardenolides in D. obscura plants are those of the series A and such predominance (ca. 80-85%) over the series B metabolites is independent of the population studied or the degree of maturity of the leaves. Primary glycosides represent ca. 50-60% of total cardenolides; this percentage did not vary among populations or with the leaf age but increased in summer and decreased in winter. A correlation analysis between plant biomass and cardenolide content showed a positive relationship of these parameters, which, accordin…
Identification of Traits Implicated in the Rhizosphere Competence of Fluorescent Pseudomonads: Description of a Strategy Based on Population and Mode…
2009
E-book; International audience; The lack of consistency of the beneficial effects of inoculated fluorescent pseudomonads has often been related to their bad survival in the rhizosphere. In this review, we describe the strategy followed over the last decade to study traits involved in the rhizosphere competence of these bacteria. The diversity of indigenous populations associated with plant roots was first compared to that of populations associated with uncultivated soils in order to identify traits that discriminate these populations. The involvement of these bacterial traits in the rhizosphere competence was then assessed by comparing the competitiveness of a wild-type strain to that of mu…
Cardenolide variation within and among natural populations of Digitalis obscura
1999
Summary Cardenolide content in 49 wild-growing Digitalis obscura plants from six natural populations on the Iberian Peninsula was determined by HPLC. Series A and B glycosides were the predominant cardenolides in all samples, but absolute values varied among and within populations. Hierarchic analysis of variance showed that the proportion of variation attributable to individuals was significantly higher than that attributable to population differences. Furthermore, analyses from greenhouse-grown plants, generated from seeds collected from selected parental genotypes, attributed nearly all the variability in cardenolide content to single plants. Some individual plants showed a leaf content …
Variation of Terpenoids Constituents in Natural Population ofCinnamomum tamala(L.) Leaves
2009
Abstract The leaves of Cinnamomum tamala L. (Lauraceae) were collected from seven plants occurring in seven different areas of Manipur and analyzed for their essential oil and eugenol contents using GC and GC/MS. The yield of the oil was found to vary from 1.5–5.6% (w/w), on a dry weight basis. A total of 79 compounds were identified in the oils. Eugenol was found as a major compound in the leaf oils and its concentration varied from 35.1–94.3% followed by α-phellandrene (1.0–25.4%).
Estudios estratégicos para la lucha contra la fascioliasis humana a nivel mundial = Strategic studies for the fight against de human fascioliasis wor…
2013
Fascioliasis is a zoonotic parasitic disease caused by Fasciola hepatica and F. gigantica. Emergence of human fascioliasis prompted a worldwide control initiative including a pilot study in several countries. Given the necessity to characterize the fasciolid populations involved, the overall aim of the present research is, first, the phenotypic characterization of faciolid adults and eggs implicated in human endemic areas, where this initiative has been implemented, through a computer image analysis system (CIAS) applied on the basis of standardized measurements. Second, new immunological techniques and their potential use as immunological diagnostic tests in those areas are evaluated. The …