Search results for "characteristics"
showing 10 items of 909 documents
Chronic high risk of intimate partner violence against women in disadvantaged neighborhoods: An eight-year space-time analysis
2020
Abstract We conducted a small-area ecological longitudinal study to analyze neighborhood contextual influences on the spatio-temporal variations in intimate partner violence against women (IPVAW) risk in a southern European city over an eight-year period. We used geocoded data of IPVAW cases with associated protection orders (n = 5867) in the city of Valencia, Spain (2011–2018). The city's 552 census block groups were used as the neighborhood units. Neighborhood-level covariates were: income, education, immigrant concentration, residential instability, alcohol outlet density, and criminality. We used a Bayesian autoregressive approach to spatio-temporal disease mapping. Neighborhoods with l…
Modulation of longevity-associated genes by estrogens or phytoestrogens.
2008
Abstract Females live longer than males. We have shown that the higher levels of estrogens in females protect them against aging, by up-regulating the expression of antioxidant, longevity-related genes, such as that of selenium-dependent glutathione peroxidase (GPx) and Mn-superoxide dismutase (Mn-SOD). Both estradiol and genistein (the most abundant phytoestrogen in soybeans) share chemical properties which confer antioxidant features to these compounds. However, the low concentration of estrogens and phytoestrogens make it unlikely that they exhibit significant antioxidant capacity in the organism. Physiological concentrations of estrogens and nutritionally relevant concentrations of geni…
Sex-specific responses to cold in a very cold-tolerant, northern Drosophila species
2021
Funding: This work was supported by Academy of Finland projects 268214 and 322980 to MK and a NERC (UK) grant NE/P000592/1 to MGR. Organisms can plastically alter resource allocation in response to changing environmental factors. For example, in harsh conditions, organisms are expected to shift investment from reproduction toward survival; however, the factors and mechanisms that govern the magnitude of such shifts are relatively poorly studied. Here we compared the impact of cold on males and females of the highly cold-tolerant species Drosophila montana at the phenotypic and transcriptomic levels. Although both sexes showed similar changes in cold tolerance and gene expression in response…
Coevolution of parental investment and sexually selected traits drives sex-role divergence
2016
Sex-role evolution theory attempts to explain the origin and direction of male–female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is …
Testosterone and oxidative stress: the oxidation handicap hypothesis
2007
Secondary sexual traits (SST) are usually thought to have evolved as honest signals of individual quality during mate choice. Honesty of SST is guaranteed by the cost of producing/maintaining them. In males, the expression of many SST is testosterone-dependent. The immunocompetence handicap hypothesis has been proposed as a possible mechanism ensuring honesty of SST on the basis that testosterone, in addition to its effect on sexual signals, also has an immunosuppressive effect. The immunocompetence handicap hypothesis has received mixed support. However, the cost of testosterone-based signalling is not limited to immunosuppression and might involve other physiological functions such as the…
Sex roles and the evolution of parental care specialization
2019
Males and females are defined by the relative size of their gametes (anisogamy), but secondary sexual dimorphism in fertilization, parental investment and mating competition is widespread and often remarkably stable over evolutionary timescales. Recent theory has clarified the causal connections between anisogamy and the most prevalent differences between the sexes, but deviations from these patterns remain poorly understood. Here, we study how sex differences in parental investment and mating competition coevolve with parental care specialization. Parental investment often consists of two or more distinct activities (e.g. provisioning and defence) and parents may care more efficiently by s…
Temperature affects the ontogeny of sexually dimorphic cuticular hydrocarbons inDrosophila melanogaster
2002
0022-0949 (Print) Journal Article Research Support, Non-U.S. Gov't; Hydrocarbons on the cuticle of mature Drosophila melanogaster flies play a crucial role in mate recognition, and protect against dehydration. We measured the effect of temperature on mature cuticular hydrocarbons (CHs) by (i) rearing two control strains at different temperatures, (ii) shifting the temperature after metamorphosis and (iii) inducing a single heat-shock pulse in control and heat-sensitive transgenic strains, over a period of 3 days following adult eclosion. This study describes the time course of the events involved in the production of male- and female-predominant CHs. We also found that 'immature' CHs, sexua…
Environmental stress affects the expression of a carotenoid-based sexual trait in male zebra finches.
2007
SUMMARY Abiotic factors including thermal stress are suggested to exert constrains on sexual ornaments through trade-offs between sexual displays and physiological functions related to self-maintenance. Given the health properties of carotenoid pigments, carotenoid-based ornaments offer a relevant context in which to investigate the effect of environmental stress, such as ambient temperature, on the production and maintenance of secondary sexual traits and, also, to explore the proximate mechanisms shaping their expression. In this study, we exposed male zebra finches (Taeniopygia guttata) to environmental stress by exposing them to two temperature regimes (6 and 26°C) over a 4 week period.…
Geographical clines in the size of the herb field mouse ( Apodemus uralensis )
2019
Patterns of body size variation along geographical gradients have long been searched for and generalized into eco-geographical rules. However, no rodent species has yet been analyzed in relation to the 3 dimensions of latitude, longitude and altitude. We analyzed geographical clines and dimorphism of body and skull size in the herb field mouse (Apodemus uralensis) across the species range, based on field data and on data from the literature. Sexual dimorphism in adult A. uralensis was not expressed at a large scale, while local patterns were inconsistent. Age-dependent size changes were most expressed in adult individuals: most characters of adults exceeded in size those of subadults, while…
A field test of behavioural flexibility in Zenaida doves (Zenaida aurita).
2010
7 pages; International audience; Animals' ability to adjust their behaviour when environmental conditions change can increase their likelihood of survival. Although such behavioural flexibility is regularly observed in the field, it has proven difficult to systematically quantify and predict inter-individual differences in free-living animals. We presented 24 Zenaida doves (Zenaida aurita) on 12 territories with two learning tests in their natural habitat in Barbados. The dove pairs showed high site fidelity and territoriality, allowing us to test individuals repeatedly while accounting for the effects of territorial chases and pair bonds on our learning measures. We used a foraging apparat…