Search results for "57"
showing 10 items of 4186 documents
Within trophic level shifts in collagen-carbonate stable carbon isotope spacing are propagated by diet and digestive physiology in large mammal herbi…
2018
Stable carbon isotope analyses of vertebrate hard tissues such as bones, teeth, and tusks provide information about animal diets in ecological, archeological, and paleontological contexts. There is debate about how carbon isotope compositions of collagen and apatite carbonate differ in terms of their relationship to diet, and to each other. We evaluated relationships between δ13Ccollagen and δ13Ccarbonate among free-ranging southern African mammals to test predictions about the influences of dietary and physiological differences between species. Whereas the slopes of δ13Ccollagen–δ13Ccarbonate relationships among carnivores are ≤1, herbivore δ13Ccollag…
Phylogeography, evolutionary history and effects of glaciations in a species (Zootoca vivipara) inhabiting multiple biogeographic regions
2018
[Aim]: During glaciations, the distribution of temperate species inhabiting the Northern Hemisphere generally contracts into southern refugia; and in boreo‐alpine species of the Northern Hemisphere, expansion from Northern refugia is the general rule. Little is known about the drivers explaining vast distributions of species inhabiting multiple biogeographic regions (major biogeographic regions defined by the European Environmental Agency). Here we investigate the fine‐scale phylogeography and evolutionary history of the Eurasian common lizard (Zootoca vivipara), the terrestrial reptile with the world's widest and highest latitudinal distribution, that inhabits multiple biogeographic region…
When Choice Makes Sense: Menthol Influence on Mating, Oviposition and Fecundity in Drosophila melanogaster
2016
International audience; The environment to which insects have been exposed as larvae and adults can affect subsequent behaviors, such as mating, oviposition, food preference or fitness. Experience can change female preference for oviposition, particularly in phytophagous insects. In Drosophila melanogaster, females avoid laying eggs on menthol rich-food when given the choice. Exposure to menthol during larval development reduces this aversion. However, this observation was not reproduced in the following generation. Recently, we have shown that oviposition-site preference (OSP) differs between wild type D. melanogaster lines freely or forcibly exposed to menthol. After 12 generations, menth…
Daphnia invest in sexual reproduction when its relative costs are reduced
2018
The timing of sex in facultatively sexual organisms is critical to fitness, due to the differing demographic consequences of sexual versus asexual reproduction. In addition to the costs of sex itself, an association of sex with the production of dormant life stages also influences the optimal use of sex, especially in environments where resting eggs are essential to survive unfavourable conditions. Here we document population dynamics and the occurrence of sexual reproduction in natural populations of Daphnia magna across their growing season. The frequency of sexually reproducing females and males increased with population density and with decreasing asexual clutch sizes. The frequency of…
Social transmission of avoidance among predators facilitates the spread of novel prey.
2018
Warning signals are an effective defence strategy for aposematic prey, but only if they are recognized by potential predators. If predators must eat prey to associate novel warning signals with unpalatability, how can aposematic prey ever evolve? Using experiments with great tits (Parus major) as predators, we show that social transmission enhances the acquisition of avoidance by a predator population. Observing another predator’s disgust towards tasting one novel conspicuous prey item led to fewer aposematic than cryptic prey being eaten for the predator population to learn. Despite reduced personal encounters with unpalatable prey, avoidance persisted and increased over subsequent trials.…
Hybridization, ecogeographical displacement and the emergence of new lineages – A genotyping‐by‐sequencing and ecological niche and species distribut…
2021
Ecogeographical displacement of homoploid hybrid lineages from their parents is well documented and considered an important mechanism to achieve reproductive isolation. In this study, we investigated the origin of the flowering plant species Sempervivum tectorum in the Massif Central (France) through homoploid hybridization between lineages of the species from the Rhine Gorge area (Germany) and the Pyrenees (France). We used genotyping-by-sequencing genetic data as evidence for the hybrid origin of the Massif Central lineage, and WorldClim climatic data and soil pH and soil temperature data collected by us for ecological niche and species distribution modelling. We could show that the Massi…
Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits.
2016
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species - the great tit Parus major - at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), u…
Little parallelism in genomic signatures of local adaptation in two sympatric, cryptic sister species.
2020
Species living in sympatry and sharing a similar niche often express parallel phenotypes as a response to similar selection pressures. The degree of parallelism within underlying genomic levels is often unexplored, but can give insight into the mechanisms of natural selection and adaptation. Here, we use multi-dimensional genomic associations to assess the basis of local and climate adaptation in two sympatric, cryptic Crematogaster levior ant species along a climate gradient. Additionally, we investigate the genomic basis of chemical communication in both species. Communication in insects is mainly mediated by cuticular hydrocarbons (CHCs), which also protect against water loss and, hence,…
Technical Note on the quality of DNA sequencing for the molecular characterisation of genetically modified plants
2018
Abstract As part of the risk assessment (RA) requirements for genetically modified (GM) plants, according to Regulation (EU) No 503/2013 and the EFSA guidance on the RA of food and feed from GM plants (EFSA GMO Panel, 2011), applicants need to perform a molecular characterisation of the DNA sequences inserted in the GM plant genome. The European Commission has mandated EFSA to develop a technical note to the applicants on, and checking of, the quality of the methodology, analysis and reporting covering complete sequencing of the insert and flanking regions, insertion site analysis of the GM event, and generational stability and integrity. This Technical Note puts together requirements and r…
Gene flow from an adaptively divergent source causes rescue through genetic and demographic factors in two wild populations of Trinidadian guppies
2016
Genetic rescue, an increase in population growth owing to the infusion of new alleles, can aid the persistence of small populations, but its use as a management tool is limited by a lack of empirical data geared towards predicting effects of gene flow on local adaptation and demography. Experimental translocations provide an ideal opportunity to monitor the demographic consequences of gene flow. In this study we take advantage of two experimental introductions of Trinidadian guppies to test the effects of gene flow on downstream native populations. We individually marked guppies from the native populations to monitor population dynamics for 3 months before and 26 months after gene flow. We …