Search results for "depression."

Inbreeding depression in an insect with maternal care: influences of family interactions, life stage and offspring sex.

2013

Although inbreeding is commonly known to depress individual fitness, the severity of inbreeding depression varies considerably across species. Among the factors contributing to this variation, family interactions, life stage and sex of offspring have been proposed, but their joint influence on inbreeding depression remains poorly understood. Here, we demonstrate that these three factors jointly shape inbreeding depression in the European earwig, Forficula auricularia. Using a series of cross-breeding, split-clutch and brood size manipulation experiments conducted over two generations, we first showed that sib mating (leading to inbred offspring) did not influence the reproductive success of…

Intergenomic interactions affect female reproduction: evidence from introgression and inbreeding depression in a haplodiploid mite

2004

Nuclear and cytoplasmic genomes can coevolve antagonistically or harmoniously to affect fitness. One commonly used test for nuclear-cytoplasmic coadaptation relies on the breakup of coadapted gene complexes by introgression, potentially resulting in an increased frequency of nuclear alleles in deleterious interaction with an alien cytoplasm. We investigated the phenotypic effect of such genes on female reproduction in outbred and inbred introgressed lines of the haplodiploid mite Tetranychus urticae. Introgression changed female lifetime fecundity and increased male production, in ways suggesting a control of fecundity by nuclear genes. Conversely introgression reduced the fertilization rat…

Inbreeding depression in intraspecific metabolic scaling

2013

Metabolic scaling (i.e., the relationship between the size and metabolic rate of organisms) has been suggested to explain a large variety of biological patterns from individual growth to species diversity. However, considerable disagreement remains regarding the underlying causes of metabolic scaling patterns, and what these patterns are. As in all biology, understanding metabolic scaling will require understanding its evolution by natural selection. We searched for evidence of natural selection on metabolic scaling indirectly by manipulating the genetic quality of male and female Drosophila montana flies with induced mutations and inbreeding, building on the notion that mutations and inbre…

Males Benefit from Mating with Outbred Females in Drosophila littoralis: Male Choice for Female Genetic Quality?

2015

The evolution and expression of mate choice behaviour in either sex depends on the sex-specific combination of mating costs, benefits of choice and constraints on choice. If the benefits of choice are larger for one sex, we would expect that sex to be choosier, assuming that the mating costs and constraints on choice are equal between sexes. Because deliberate inbreeding is a powerful genetic method for experimental manipulation of the quality of study organisms, we tested the effects of both male and female inbreeding on egg and offspring production in Drosophila littoralis. Female inbreeding significantly reduced offspring production (mostly due to lower egg-to-adult viability), whereas m…

Similar Performance of Diploid and Haploid Males in an Ant Species without Inbreeding Avoidance

2013

AbstractUnder haplodiploidy, a characteristic trait of all Hymenoptera, femalesdevelop from fertilised eggs, and males from unfertilised ones. Males aretherefore typically haploid. Yet, inbreeding can lead to the production ofdiploid males that often fail in development, are sterile or are of lowerfertility. In most Hymenoptera, inbreeding is avoided by dispersal flightsof one or both sexes, leading to low diploid male loads. We investigatedcauses for the production of diploid males and their performance in ahighly inbred social Hymenopteran species. In the ant Hypoponera opacior,inbreeding occurs between wingless sexuals, which mate within themother nest, whereas winged sexuals outbreed dur…

Inbreeding rate modifies the dynamics of genetic load in small populations

2012

The negative fitness consequences of close inbreeding are widely recognized, but predicting the long-term effects of inbreeding and genetic drift due to limited population size is not straightforward. As the frequency and homozygosity of recessive deleterious alleles increase, selection can remove (purge) them from a population, reducing the genetic load. At the same time, small population size relaxes selection against mildly harmful mutations, which may lead to accumulation of genetic load. The efficiency of purging and the accumulation of mutations both depend on the rate of inbreeding (i.e., population size) and on the nature of mutations. We studied how increasing levels of inbreeding …

Inbreeding, energy use and condition

2009

In energetic terms, fitness may be seen to be dependent on successful allocation of energy between life-history traits. In addition, fitness will be constrained by the energy allocation ability, which has also been defined as condition. We suggest here that the allocation ability, estimated as the difference between total energy budget and maintenance metabolism, may be used as a measure of condition. We studied this possibility by measuring the resting metabolic rate and metabolism during forced exercise in Gryllodes sigillatus crickets. To verify that these metabolic traits are closely related to fitness, we experimentally manipulated the degree of inbreeding of individuals belonging to t…

Conan Fischer, A Vision of Europe. Franco-German Relations during the Great Depression, 1929–1932. Oxford, Oxford University Press 2017

2018

Factors associated with fear of falling among frail older adults

2021

Some factors increase the fear of falling in frail older adults. Our aim is to quantify the influence of these factors. This cross-sectional study involved 229 community-dwelling prefrail and frail older adults aged 70 years and older. Fear of falling was moderate in 38.9% of our sample and high in 12.2%. Higher values were observed in women, those living alone, and those meeting criteria for slowness and feelings of exhaustion. A linear regression showed that being a woman, a history of falls, and depressive symptoms were related to higher fear of falling, while high levels of independence in basic and instrumental activities of daily living, along with good gait and balance, were associat…

Life satisfaction, distress, and resiliency across the life span of women.

2009

Objective: This study aimed to determine (1) the relationship between life satisfaction, mental disorders, and aging in the female community and (2) to identify the impact of vulnerability factors, personal (resilience, self-esteem), and social resources on life satisfaction and distress. Methods: A stratified random sample of the German female population (N = 2,540) was investigated using standardized questionnaires of life satisfaction (Questions on Life Satisfaction), depression, anxiety (Patient Health Questionnaire), resilience scale (RS-11), and self-esteem (Rosenberg Self-Esteem Scale). Results: When participants were divided into six age groups (18-30, 31-40, 41-50, 51-60, 61-70, an…