Search results for "Population Dynamic"
showing 10 items of 296 documents
Numerical solution of a spatio-temporal gender-structured model for hantavirus infection in rodents.
2017
In this article we describe the transmission dynamics of hantavirus in rodents using a spatio-temporal susceptible-exposed-infective-recovered (SEIR) compartmental model that distinguishes between male and female subpopulations [L.J.S. Allen, R.K. McCormack and C.B. Jonsson, Bull. Math. Biol. 68 (2006), 511--524]. Both subpopulations are assumed to differ in their movement with respect to local variations in the densities of their own and the opposite gender group. Three alternative models for the movement of the male individuals are examined. In some cases the movement is not only directed by the gradient of a density (as in the standard diffusive case), but also by a non-local convolution…
Evidence for an Association between Post-Fledging Dispersal and Microsatellite Multilocus Heterozygosity in a Large Population of Greater Flamingos
2013
10 pages; International audience; DISPERSAL CAN BE DIVIDED INTO THREE STAGES: departure, transience and settlement. Despite the fact that theoretical studies have emphasized the importance of heterozygosity on dispersal strategies, empirical evidence of its effect on different stages of dispersal is lacking. Here, using multi-event capture-mark-recapture models, we show a negative association between microsatellite multilocus heterozygosity (MLH; 10 loci; n = 1023) and post-fledging dispersal propensity for greater flamingos, Phoenicopterus roseus, born in southern France. We propose that the negative effects of inbreeding depression affects competitive ability and therefore more homozygous…
Laboratory relationships between adult lifetime reproductive success and fitness surrogates in a Drosophila littoralis population.
2011
The difficulties in measuring total fitness of individuals necessitate the use of fitness surrogates in ecological and evolutionary studies. These surrogates can be different components of fitness (e.g. survival or fecundity), or proxies more uncertainly related to fitness (e.g. body size or growth rate). Ideally, fitness would be measured over the lifetime of individuals; however, more convenient short-time measures are often used. Adult lifetime reproductive success (adult LRS) is closely related to the total fitness of individuals, but it is difficult to measure and rarely included in fitness estimation in experimental studies. We explored phenotypic correlations between female adult LRS…
Identifying Genetic Traces of Historical Expansions: Phoenician Footprints in the Mediterranean
2008
10 páginas, 1 figura, 4 páginas.-- et al.
Assortative mating and fertility in two Drosophila subobscura strains with different mitochondrial DNA haplotypes.
2003
The mating pattern and female fertility on the two main mitochondrial DNA haplotypes (I and II) of Drosophila subobscura were studied, in an attempt to find possible differences between them in relation to sexual selection or isolation that could explain the populational dynamics and the co-existence of these two strains in nature. The mating pattern indicated an assortative mating in population cages, where couples of the same haplotype, mainly those of haplotype I, mated more often. However, the significations detected in laboratory conditions disappeared in wild populations, where random mating was the rule. The female fertility also showed differences in the laboratory compared to the w…
Stability of Corynosoma populations with fluctuating population densities of the seal definitive host.
2004
In theory there should be a strong coupling between host and parasite population sizes. Here, we investigated population size and structure in 3 species of acanthocephalans,Corynosoma semerme,C. strumosumandC. magdaleni, in ringed seals (Phoca hispida) from the Bothnian Bay over a period of more than 20 years. During this period, seal numbers first decreased markedly and then increased steadily; at the same time, a paratenic fish host particularly important forC. strumosumhas gradually disappeared from the bay due to decreasing salinity. We found no evidence that the mean abundance of any of the 3 acanthocephalan species changed significantly over time, nor was there any relationship betwee…
Canal construction destroys the barrier between major European invasion lineages of the zebra mussel.
2002
Since the mid-1980s the zebra mussel, Dreissena polymorpha, Pallas 1771, has become the protagonist of a spectacular freshwater invasion in North America due to its large economic and biological impact. Several genetic studies on American populations have failed to detect any large-scale geographical patterns. In western Europe, where D. polymorpha has been a classical invader from the Pontocaspian since the early 19th century, the situation is strikingly different. Here, we show with genetic markers that two major western European invasion lineages with lowered genetic variability within and among populations can be discriminated. These two invasion lineages correspond with two separate na…
Seasonal dynamics of atlantic herring (Clupea harengus L.) populations spawning in the vicinity of marginal habitats
2014
Published version of an article from the journal PLoS One. Also available from the publisher: http://dx.doi.org/10.1371/journal.pone.0111985 Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L.) populations mixing together over the spawning season February–June inside and outside an inland brackish water lake (Landvikvannet) in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March–April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May–June with high proportions f…
Predominance of outcrossing in Lymnaea stagnalis despite low apparent fitness costs of self-fertilization.
2007
We have quantified the natural mating system in eight populations of the simultaneously hermaphroditic aquatic snail Lymnaea stagnalis, and studied the ecological and genetic forces that may be directing mating system evolution in this species. We investigated whether the natural mating system can be explained by the availability of mates, by the differential survival of self- and cross-fertilized snails in nature, and by the effects of mating system on parental fecundity and early survival. The natural mating system of L. stagnalis was found to be predominantly cross-fertilizing. Density of snails in the populations had no relationship with the mating system, suggesting that outcrossing ra…
Helminth communities of two green frogs (Rana perezi and Rana saharica) from both shores of the Alboran Sea.
2006
Les communautes d'helminthes de deux populations de grenouilles vertes des rivages de la mer d'Alboran (mediterraneen occidental) ont ete etudiees. Des 79 grenouilles examinees pour etudier les helminthes, 39 exemplaires de Rana saharica ont ete captures a Bab-Taza (Maroc), et 40 de l'espece Rana perezi dans le Parc Naturel Sierra de Grazalema (Espagne). Bien que la richesse des especes d'helminthes soient identique dans les deux secteurs d'echantillonnage, les differences observees dans la structure des infracommunautes d'helminthes sont assez importantes. Statistiquement, des differences significatives ont ete trouvees entre la richesse en especes et la diversite des infracommunautes chez…