Search results for "selection"
showing 10 items of 1940 documents
Data from: Intensity of male-male competition predicts morph diversity in a colour polymorphic lizard
2017
Sexual selection is one of the main processes involved in the emergence and maintenance of heritable colour polymorphisms in a variety of taxa. Here we test whether the intensity of sexual selection, estimated from population sex ratio, predicts morph diversity in Podarcis muralis, a colour polymorphic lizard with discrete white, yellow, orange, white-orange, and yellow-orange male and female phenotypes (i.e. morphs). In a sample of 116 Pyrenean populations and 5421 lizards, sex ratios (m/f) vary from 0.29 to 2.5, with the number of morphs for each sex ranging from 2 to 5. Male-biased sex ratios are associated with increased morph diversity as measured with Shannon's diversity index. The ma…
Data from: Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm compet…
2017
Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early-stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the same populations to test whether competitive effects between ejaculates influe…
Data from: Negative frequency-dependent selection of sexually antagonistic alleles in Myodes glareolus
2011
Sexually antagonistic genetic variation, where optimal values of traits are sex-dependent, is known to slow the loss of genetic variance associated with directional selection on fitness-related traits. However, sexual antagonism alone is not sufficient to maintain variation indefinitely. Selection of rare forms within the sexes can help to conserve genotypic diversity. We combined theoretical models and a field experiment with Myodes glareolus to show that negative frequency-dependent selection on male dominance maintains variation in sexually antagonistic alleles. In our experiment, high-dominance male bank voles were found to have low-fecundity sisters, and vice versa. These results show …
Data from: Fluctuating temperature leads to evolution of thermal generalism and preadaptation to novel environments
2013
Environmental fluctuations can select for generalism, which is also hypothesized to increase organisms’ ability to invade novel environments. Here, we show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24°C and 38°C, mean 31°C) outperforms the strains that evolved in constant temperature (31°C). The growth advantage was also evident in novel environments in the presence of parasitic viruses and predatory protozoans, but less clear in the presence of stressful chemicals. Adaptation to fluctuating temperature also led to reduced virulence in Drosophila melanogaster host, which suggests…
Data from: Very high MHC Class IIB diversity without spatial differentiation in the Mediterranean population of Greater Flamingos
2017
MHC Class II Genotype data Greater Flamingo MHC Class IIB genoptype data of four Mediterranean breeding colonies: France, Spain, Algeria and Turkey MHCClassIIGenotypeGreaterFlamingo.xlsx
Data from: Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster
2013
Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer t…
Data from: The evolutionary dynamics of adaptive virginity, sex-allocation and altruistic helping in haplodiploid animals
2017
In haplodiploids, females can produce sons from unfertilized eggs without mating. However, virgin reproduction is usually considered to be a result of a failure to mate, rather than an adaptation. Here we build an analytical model for evolution of virgin reproduction, sex-allocation, and altruistic female helping in haplodiploid taxa. We show that when mating is costly (e.g. when mating increases predation risk), virginity can evolve as an adaptive female reproductive strategy. Furthermore, adaptive virginity results in strongly divergent sex-ratios in mated and virgin queen nests (‘split sex ratios’), which promotes the evolution of altruistic helping by daughters in mated queen nests. How…
Social Entrepreneurship: Where to Go Next?
2021
This chapter summarizes the main conclusions of the micro perspective section. It revises the foundations of the social entrepreneurs and outlines a path for future avenues of social entrepreneurship. However, although the unit of analysis is the individual, this does not mean that it is an individual phenomenon. In fact, it can be considered as a widespread collective phenomenon, that is, the small initiative of a social entrepreneur at a local level can also be successfully replicated in other places around the globe. The social entrepreneur becomes himself through the influences and motivations of the environment, added to his innate and unique characteristics, these intrinsic motivation…
Recognition of Cardiac Arrhythmia by Means of Beat Clustering on ECG-Holter Recordings
2012
The follow-up of some cardiac diseases may be achieved by ECG-holter record analysis. A heartbeat clustering method can be used to reduce the usually high computational cost of such Holter analysis. This study describes a method aimed at cardiac arrhythmia recognition based on this approach, by means of unsupervised inspection of morphologically similar heartbeat groups. Singular Value Decomposition (SVD) is used as the feature selection method since the complexity increases exponentially with the number of features. A modification of the k-means algorithm was developed for centroid computation, taking into account heartbeat length changes. Experimental set consisted of ECG records from the…