Search results for " selection"
showing 10 items of 1271 documents
Personality may confound common measures of mate-choice.
2011
5 pages; International audience; The measurement of female mating preferences is central to the study of the evolution of male ornaments. Although several different methods have been developed to assess sexual preference in some standardized way, the most commonly used procedure consists of recording female spatial association with different males presented simultaneously. Sexual preference is then inferred from time spent in front of each male. However, the extent to which the measurement of female mate-choice is related to exploration tendencies has not been addressed so far. In the present study we assessed the influence of variation in exploration tendencies, a trait closely associated …
The evolution of mating preferences for genetic attractiveness and quality in the presence of sensory bias.
2022
The aesthetic preferences of potential mates have driven the evolution of a baffling diversity of elaborate ornaments. Which fitness benefit—if any—choosers gain from expressing such preferences is controversial, however. Here, we simulate the evolution of preferences for multiple ornament types (e.g., “Fisherian,” “handicap,” and “indicator” ornaments) that differ in their associations with genes for attractiveness and other components of fitness. We model the costs of preference expression in a biologically plausible way, which decouples costly mate search from cost-free preferences. Ornaments of all types evolved in our model, but their occurrence was far from random. Females typically p…
Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity
2021
Abstract Background Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host–pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexua…
Negatively condition dependent predation cost of a positively condition dependent sexual signalling.
2006
Predation is considered as an important factor constraining the expression of sexual signals. Nevertheless, direct quantitative evidence for predation provoking significant viability costs on individuals signalling at high rates is scarce. Moreover, it is unclear whether high rate signallers are able to balance presumably increased predation costs. We examined whether a condition dependent audible sexual signal, drumming, makes Hygrolycosa rubrofasciata male spiders more prone to predation by pied flycatchers (Ficedula hypoleuca), and whether sexual signalling rate is related to escaping ability once attacked. When birds were given a choice between two spider males manipulated to drum eithe…
Empirical study of the dependence of the results of multivariable flexible survival analyses on model selection strategy
2008
Flexible survival models, which avoid assumptions about hazards proportionality (PH) or linearity of continuous covariates effects, bring the issues of model selection to a new level of complexity. Each ‘candidate covariate’ requires inter-dependent decisions regarding (i) its inclusion in the model, and representation of its effects on the log hazard as (ii) either constant over time or time-dependent (TD) and, for continuous covariates, (iii) either loglinear or non-loglinear (NL). Moreover, ‘optimal’ decisions for one covariate depend on the decisions regarding others. Thus, some efficient model-building strategy is necessary. We carried out an empirical study of the impact of the model …
INTERSPECIFIC AGGRESSION CAUSES NEGATIVE SELECTION ON SEXUAL CHARACTERS
2005
Interspecific aggression originating from mistaken species recognition may cause selection on secondary sexual characters, but this hypothesis has remained untested. Here we report a field experiment designed to test directly whether interspecific aggression causes selection on secondary sexual characters, wing spots, in wild damselfly populations. Males of Calopteryx virgo are more aggressive toward males of C. splendens with large than with small wing spots. This differential interspecific aggression may cause negative selection on wing spot size. Indeed, our results show that directional survival selection on wing spot size of C. splendens males was changed by experimental removal of C. …
Social behavior, chemical communication, and adult neurogenesis: Studies of scent mark function in Podarcis wall lizards
2011
Lacertid lizards have been hailed as a model system for the study of reptilian chemical communication. However, results obtained with the genus Podarcis, a diverse group of wall lizards with complex systematics, challenge emerging paradigms and caution against hasty generalizations. Here we review the available evidence on the role of chemical stimuli in male-female and male-male interactions in Iberian Podarcis. Males of several species can discriminate between chemicals left on substrates by females of their own or a different species, suggesting that differences in female chemical cues may underlie species recognition in this group. Females, on the other hand, do not respond differential…
Simultaneous age‐dependent and age‐independent sexual selection in the lekking black grouse(Lyrurus tetrix)
2014
Individuals' reproductive success is often strongly associated with their age, with typical patterns of early‐life reproductive improvement and late‐life senescence. These age‐related patterns are due to the inherent trade‐offs between life‐history traits competing for a limited amount of resources available to the organisms. In males, such trade‐offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their life span. Due to the age dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitu…
Do randomized clinical trial selection criteria reflect levels of risk as observed in a general population of acute myocardial infarction survivors? …
2016
IF 4.638; International audience; Background: Few clinical trials have focused on populations with a history of distant myocardial infarction (MI). The PEGASUS trial assessed the impact of dual antiplatelet therapy in such patients, selected by enrichment criteria of high cardiovascular risk. Whether the PEGASUS population reflects the risk of a broader post-MI population is questionable. We analyzed whether 4-year mortality of a routine-practice population would differ according to the inclusion and exclusion criteria used in PEGASUS.Methods: FAST-MI is a nationwide French registry recruiting acute MI patients in November 2005; 2490 patients alive and without recurrent MI at one year were …
Mid-term Results of Chimney and Periscope Grafts in Supra-aortic Branches in High Risk Patients
2017
Purpose Report mid-term outcomes of thoracic endovascular aneurysm repair (TEVAR) with chimney and periscope grafts (CPG) in supra-aortic branches (SAB). Methods Retrospective analysis, from October 2009 to May 2014, of patients with aneurysms requiring TEVAR with zone 0/1/2 proximal landing in association with at least one CPG in the SAB. All patients were considered at high risk for conventional surgery. Peri-operative mortality and morbidity, retrograde type A dissection, maximum aortic transverse diameter (TD) and its post-operative evolution, endoleak, survival, freedom from cardiovascular re-interventions, and CPG freedom from occlusion during the follow-up were analysed. Results Fort…