Search results for "Isolation"
showing 10 items of 582 documents
Postcopulatory sexual selection generates speciation phenotypes in Drosophila.
2013
Background: Identifying traits that reproductively isolate species and the selective forces underlying their divergence is a central goal of evolutionary biology and speciation research. There is growing recognition that postcopulatory sexual selection which can drive rapid diversification of interacting ejaculate and female reproductive tract traits that mediate sperm competition may be an engine of speciation. Conspecific sperm precedence (CSP) is a taxonomically widespread form of reproductive isolation but the selective causes and divergent traits responsible for CSP are poorly understood. Results: To test the hypothesis that postcopulatory sexual selection can generate reproductive iso…
Phenotypic Divergence among West European Populations of Reed Bunting Emberiza schoeniclus: The Effects of Migratory and Foraging Behaviours
2013
[EN] Divergent selection and local adaptation are responsible for many phenotypic differences between populations, potentially leading to speciation through the evolution of reproductive barriers. Here we evaluated the morphometric divergence among west European populations of Reed Bunting in order to determine the extent of local adaptation relative to two important selection pressures often associated with speciation in birds: migration and diet. We show that, as expected by theory, migratory E. s. schoeniclus had longer and more pointed wings and a slightly smaller body mass than the resident subspecies, with the exception of E. s. lusitanica, which despite having rounder wings was the s…
Genomic Analysis of European Drosophila melanogaster Populations Reveals Longitudinal Structure, Continent-Wide Selection, and Previously Unknown DNA…
2020
Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatiotemporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, ide…
Gene flow relates to evolutionary divergence among populations at the range margin
2020
Background Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel’s bush-cricket, Metrioptera roeselii, populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species. Methods To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of …
Out of the Black Sea: phylogeography of the invasive killer shrimp Dikerogammarus villosus across Europe.
2015
20 pages; International audience; The amphipod Dikerogammarus villosus has colonized most of the European main inland water bodies in less than 20 years, having deteriorating effect on the local benthic communities. Our aim was to reveal the species phylogeography in the native Black Sea area, to define the source populations for the colonization routes in continental Europe and for the newly established UK populations. We tested for the loss of genetic diversity between source and invasive populations as well as along invasion route. We tested also for isolation by distance. Thirty three native and invasive populations were genotyped for mtDNA (COI, 16S) and seven polymorphic nuclear micro…
Reinforcement targets sexual or postmating prezygotic reproductive barriers depending on species abundance and population history
2018
AbstractThe impact of different reproductive barriers on species or population isolation may vary in different stages of speciation depending on evolutionary forces acting within species and through species’ interactions. Genetic incompatibilities between interacting species are expected to reinforce prezygotic barriers in sympatric populations and create character displacement between conspecific populations living within and outside the area of sympatry. The outcome of reinforcement has been suggested to be affected by the strength of postzygotic barriers, the history of species coexistence, and the impact of species abundancies on females’ discrimination against heterospecific males. We …
Dispersal flight and colony development in the fungus-growing termites Pseudacanthotermes spiniger and P. militaris
2012
International audience; Pseudacanthotermes spiniger and P. militaris are two African fungus-growing termites (Termitidae, Macrotermitinae) which may become pests in disturbed agrosystems where they often live in sympatry. To study their development and their reproductive strategies, colonies of both species were reared in the laboratory for 20 and 17 years, respectively, after their foundation from reproductive pairs. The first steps of development were in great part similar in both species, although P. spiniger favoured the defence during the juvenile period, while P. militaris tended to favour a rapid development. While P. spiniger colonies did not produce alates until year 7 of colony li…
Colonisation and diversification of the Zenaida dove (Zenaida aurita) in the Antilles: phylogeography, contemporary gene flow and morphological diver…
2013
12 pages; International audience; Caribbean avifaunal biogeography has been mainly studied based on mitochondrial DNA. Here, we investigated both past and recent island differentiation and micro-evolutionary changes in the Zenaida Dove (Zenaida aurita) based on combined information from one mitochondrial (Cytochrome c Oxydase subunit I, COI) and 13 microsatellite markers and four morphological characters. This Caribbean endemic and abundant species has a large distribution, and two subspecies are supposed to occur: Z. a. zenaida in the Greater Antilles (GA) and Z. a. aurita in the Lesser Antilles (LA). Doves were sampled on two GA islands (Puerto Rico and the British Virgin Islands) and six…
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla
2005
Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake ( Rissa tridactyla ) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae . Parasites were …
Can the problem of hybridization in threatened species be evaluated using a fieldwork research? A case study in snapdragons
2019
Abstract Hybridization, natural or artificial, is considered disadvantageous for species biodiversity when it threatens the population integrity of endangered species. Frequently, studies investigating whether hybridization poses a legitimate risk to rare species are based on genetic data obtained in molecular biology laboratories. In this study, we used field research to approach the problem that hybridization could cause for the viability of a population of a rare species and to be able to propose the most appropriate initial conservation strategy. Specifically, using the model genus Antirrhinum, the reproductive barriers between the rare A. pulverulentum and its common congener A. litigi…