scholarly journals Inbreeding removes sex differences in lifespan in a population of Drosophila melanogaster

2016 ◽  
Vol 12 (6) ◽  
pp. 20160337 ◽  
Author(s):  
Pau Carazo ◽  
Jared Green ◽  
Irem Sepil ◽  
Tommaso Pizzari ◽  
Stuart Wigby
Keyword(s):  
Sex Differences ◽  
Drosophila Melanogaster ◽  
Evolutionary Biology ◽  
Social Effects ◽  
Same Sex ◽  
Deleterious Alleles ◽  
The Social ◽  
Specific Mortality ◽  
Males And Females ◽  
Female Lifespan

Sex differences in ageing rates and lifespan are common in nature, and an enduring puzzle for evolutionary biology. One possibility is that sex-specific mortality rates may result from recessive deleterious alleles in ‘unguarded’ heterogametic X or Z sex chromosomes (the unguarded X hypothesis). Empirical evidence for this is, however, limited. Here, we test a fundamental prediction of the unguarded X hypothesis in Drosophila melanogaster , namely that inbreeding shortens lifespan more in females (the homogametic sex in Drosophila ) than in males. To test for additional sex-specific social effects, we studied the lifespan of males and females kept in isolation, in related same-sex groups, and in unrelated same-sex groups. As expected, outbred females outlived outbred males and inbreeding shortened lifespan. However, inbreeding-mediated reductions in lifespan were stronger for females, such that lifespan was similar in inbred females and males. We also show that the social environment, independent of inbreeding, affected male, but not female lifespan. In conjunction with recent studies, the present results suggest that asymmetric inheritance mechanisms may play an important role in the evolution of sex-specific lifespan and that social effects must be considered explicitly when studying these fundamental patterns.

scholarly journals Morphometric Correlates of Age and Breeding Status in American Coots

The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 640-646 ◽  
Author(s):  
Ray T. Alisauskas
Keyword(s):  
Body Size ◽  
Multivariate Techniques ◽  
Same Sex ◽  
Linear Measurements ◽  
Morphometric Variation ◽  
Size And Shape ◽  
Multivariate Dispersion ◽  
Age Related ◽  
The Social ◽  
Males And Females

Abstract I studied morphometric variation in 13 linear measurements from 228 American Coots (Fulica americana) collected in southern Manitoba. Univariate and multivariate techniques revealed differences in size and shape among adult coots that were 1, 2, and =2 yr old. In addition to the obvious differences in size between males and females, the morphometry of older birds differed from that of younger birds in two ways. First, older coots were of larger body size than younger coots of the same sex. Second, older coots had proportionately larger feet and claws relative to the size of their tarsi, and proportionately wider bills and heads relative to other head measurements, than did younger birds. Multivariate dispersion matrices within age/sex cohorts were less variable for older coots. In an analysis of 1-yr-old males, breeders did not differ from nonbreeders in overall body size, but breeders had relatively longer claws and wings than nonbreeders. Age-related differences in morphology may have relevance to the social structure of nesting coots, which involves highly aggressive territorial behavior. Part of the age-related variation in nesting phenology that has been documented elsewhere for coots may be a consequence of covariation in body size and shape.

Sex Differences in Response to Marijuana in a Social Setting

1978 ◽  
Vol 2 (4) ◽  
pp. 334-353 ◽  
Author(s):  
Cannie Stark Adamec ◽  
R. O. Pihl
Keyword(s):  
Sex Differences ◽  
Social Interactions ◽  
Person Perception ◽  
Experimental Investigations ◽  
Social Setting ◽  
Social Situations ◽  
Performance Variables ◽  
The Social ◽  
The Subject ◽  
Males And Females

Due to the failure to include women in the subject samples of most experimental investigations of the effects of cannabis, the possibility exists that the data obtained on this social intoxicant are applicable to only 49% of the population. Those few studies that have compared males and females have focused on performance variables and have demonstrated very few differences. It was hypothesized that the most likely area for male/female marijuana differences would be that of social interactions and behaviors related to these interactions. In a relaxed, informal atmosphere, Es videotaped the social interactions of groups of female friends, female strangers, male friends, or male strangers as they smoked coltsfoot, placebo, and marijuana. In addition to social-condition and drug-condition differences, we obtained statistically significant effects indicating that the women responded both to the social situations and to the drug differently from the men. In general, the women interacted with each other more positively than did the men. These effects were paralleled by sex differences in mood, person perception, and even in how pleasurable or annoying the experimental tasks were. These data are of import not only in the area of cannabis research but in the field of social interactions and the study of female/male differences as well.

Sex Differences in Patterns of Association Among Indian Ocean Bottlenose Dolphins

Behaviour ◽  
1992 ◽  
Vol 123 (1-2) ◽  
pp. 38-69 ◽  
Author(s):  
Rachel A. Smolker ◽  
Andrew F. Richards ◽  
Richard C. Connor ◽  
John W. Pepper
Keyword(s):  
Sex Differences ◽  
Bottlenose Dolphins ◽  
Same Sex ◽  
Reproductive State ◽  
Discrete Subgroups ◽  
Party Size ◽  
Shark Bay ◽  
Association Coefficients ◽  
Males And Females

AbstractPatterns of association among bottlenose dolphins resident in Shark Bay, Western Australia were analyzed using party membership data. Parties contained an average of 4.8 individuals, but party size and composition were unstable. While these temporary parties often contained both males and females, long term consistent associations generally were between members of the same sex. The highest association coefficients, resulting from very frequent co-occurrence within parties were between males and between mothers and offspring. Males formed subgroups of two or three individuals who consistently associated with each other, and these were stable over periods of at least seven years in some cases. Male subgroups preferentially associated with particular other male subgroups. Females associated most consistently with other females, although not to the same extent as some males. Female associations were better described as a network rather than discrete subgroups. Male-female associations were generally inconsistent and depended in part on female reproductive state. Mothers and their offspring associated very consistently for at least 4 years.

scholarly journals The genetic and social contributions to sex differences in lifespan in Drosophila serrata

2021 ◽  
Author(s):  
Vikram P. Narayan ◽  
Alastair J. Wilson ◽  
Stephen F. Chenoweth
Keyword(s):  
Sex Differences ◽  
Experimental Approach ◽  
Social Background ◽  
Social Effects ◽  
Mating Status ◽  
X Chromosomes ◽  
Deleterious Alleles ◽  
Social Contributions ◽  
Drosophila Serrata ◽  
Different Levels

AbstractSex differences in lifespan remain an intriguing puzzle for evolutionary biologists. A possible explanation for lower lifespan in males is the unconditional expression of recessive deleterious alleles in heterogametic X chromosomes in males (the unguarded X hypothesis). Empirical evidence, however, has yielded controversial results that can be attributed to differences in both genetic and social background. Here, we test the unguarded X hypothesis in Drosophila serrata using a factorial design to quantify the effects of genotype, sex, social environment, and their interactions on phenotypic variation for lifespan. Using an experimental approach, we manipulated two inbred laboratory genotypes and their reciprocal F1s, while controlling for different levels of density and mating status to account for any potential social effects. Our results also show subtle but significant genotype dependent effects for both density and mating, but ultimately find the unguarded X hypothesis insufficient to fully explain sexual dimorphism in D. serrata lifespan.

scholarly journals Estimating adult sex ratios in nature

2017 ◽  
Vol 372 (1729) ◽  
pp. 20160313 ◽  
Author(s):  
Sergio Ancona ◽  
Francisco V. Dénes ◽  
Oliver Krüger ◽  
Tamás Székely ◽  
Steven R. Beissinger
Keyword(s):  
Sex Differences ◽  
Sex Ratio ◽  
Evolutionary Biology ◽  
Adult Population ◽  
Sex Ratios ◽  
Estimation Methods ◽  
Spatial And Temporal Variation ◽  
Animal Populations ◽  
Adult Sex Ratio ◽  
Males And Females

Adult sex ratio (ASR, the proportion of males in the adult population) is a central concept in population and evolutionary biology, and is also emerging as a major factor influencing mate choice, pair bonding and parental cooperation in both human and non-human societies. However, estimating ASR is fraught with difficulties stemming from the effects of spatial and temporal variation in the numbers of males and females, and detection/capture probabilities that differ between the sexes. Here, we critically evaluate methods for estimating ASR in wild animal populations, reviewing how recent statistical advances can be applied to handle some of these challenges. We review methods that directly account for detection differences between the sexes using counts of unmarked individuals (observed, trapped or killed) and counts of marked individuals using mark–recapture models. We review a third class of methods that do not directly sample the number of males and females, but instead estimate the sex ratio indirectly using relationships that emerge from demographic measures, such as survival, age structure, reproduction and assumed dynamics. We recommend that detection-based methods be used for estimating ASR in most situations, and point out that studies are needed that compare different ASR estimation methods and control for sex differences in dispersal. This article is part of the themed issue ‘Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies’.

scholarly journals Social environment drives sex and age-specific variation in Drosophila melanogaster microbiome composition and predicted function

2020 ◽  
Author(s):  
Thomas Leech ◽  
Laurin McDowall ◽  
Kevin P Hopkins ◽  
Steven M Sait ◽  
Xavier A. Harrison ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Social Environment ◽  
Social Contact ◽  
Social Effects ◽  
Social Environments ◽  
Microbiome Composition ◽  
Individual Health ◽  
The Social ◽  
Social Partners ◽  
Host Health

AbstractSocial environments influence multiple traits of individuals including immunity, stress and ageing, often in sex-specific ways. The composition of the microbiome (the assemblage of symbiotic microorganisms within a host) is determined by environmental factors and the host’s immune, endocrine and neural systems. The social environment could alter host microbiomes extrinsically by affecting transmission between individuals, likely promoting homogeneity in the microbiome of social partners. Alternatively, intrinsic effects arising from interactions between the microbiome and host physiology (the microbiota-gut-brain axis) could translate social stress into dysbiotic microbiomes, with consequences for host health. We investigated how manipulating social environments during larval and adult life-stages altered the microbiome composition of Drosophila melanogaster fruit flies. We used social contexts that particularly alter the development and lifespan of males, predicting that any intrinsic social effects on the microbiome would therefore be sex-specific. The presence of adult males during the larval stage significantly altered the microbiome of pupae of both sexes. In adults, same-sex grouping increased bacterial diversity in both sexes. Importantly, the microbiome community structure of males was more sensitive to social contact at older ages, an effect partially mitigated by housing focal males with young rather than co-aged groups. Functional analyses suggest that these microbiome changes impact ageing and immune responses. This is consistent with the hypothesis that the substantial effects of the social environment on individual health are mediated through intrinsic effects on the microbiome, and provides a model for understanding the mechanistic basis of the microbiota-gut-brain axis.Significance statementThe social environment has pervasive, multifaceted effects on individual health and fitness. If a host’s microbiome is sensitive to the social environment then it could be an important mediator of social effects, as the reciprocal relationships between hosts and their microbiomes have substantial implications for host health. Using a Drosophila melanogaster fruit fly model we show that the fly microbiome is sensitive to the social environment in a sex, age and life-stage dependent manner. In particular, older adult male microbiome communities are altered by same-sex social contact, but this depends on the age of the social partners. These changes have functional effects on fly immunity and lifespan, evidence that indeed this is an influential mediator of social effects on health.

WOMEN WHO HAVE KILLED: THE PSYCHO-SOCIAL EFFECTS OF PRISON LIFE

Imbizo ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 55-70
Author(s):  
Zanele Nyamakai ◽  
Barbra Chiyedza Manyarara
Keyword(s):  
Female Offenders ◽  
Social Effects ◽  
Theoretical Frameworks ◽  
Cultural Traditions ◽  
Prison Life ◽  
Unresolved Grief ◽  
The Social ◽  
Form Part ◽  
Women In Prison ◽  
Males And Females

The female ex-prisoners interviewed in the semi-autobiographical collection A tragedy of lives: Women in prison in Zimbabwe (2003) caused the deaths of their own loved ones, consequently they were unable to mourn or bury them. The processing of the homicides precludes these women going through the appropriate rites and rituals which ordinarily form part of deaths in Zimbabwean cultural traditions. Variously manifesting in the experiences of the different women interviewed, the complex psychiatric and psychological problems observed in these women are attributable to incomplete mourning and unresolved grief which are linked to the social inadequacies of a necessarily truncated expression of that grief. The present textual analysis is dually guided by Africana womanist and psychoanalytic theoretical frameworks. The study establishes a shift by Zimbabwean women writers from merely highlighting issues that affect women, to taking a stance on the effects of imprisonment on female offenders both during and after incarceration. Empathy and optimism are shown towards the interviewees. The semi-autobiography also enables the generality of Zimbabweans to understand the effects of such crimes and the need to rehabilitate offenders. The study encourages harmonious co-existence between males and females in the postcolony.

THE STRUCTURE OF MASCULINITY-FEMININITY: MULTIDIMENSIONALITY AND GENDER DIFFERENCES

1981 ◽  
Vol 9 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Elyse Sutherland Ratliff ◽  
James Conley
Keyword(s):  
Gender Differences ◽  
Sex Differences ◽  
Social Dominance ◽  
Sex Role ◽  
Strongly Correlated ◽  
Specific Content ◽  
Psychological Androgyny ◽  
The Social ◽  
Males And Females ◽  
And Gender

In an investigation of the structure of sex role self-descriptors, the responses of 176 female and 103 male undergraduates to the Bern Sex Role Inventory (BSRI) were factor analyzed. Seven factors emerged: Personal Warmth, Social Dominance, Autonomy, Affect, M-F, Vulnerability, and Responsibility, four of which are composed of sex-typed BSRI items. Sex differences were found in the scores on the Personal Warmth and M-F factors, and somewhat different factor structures emerged for males than for females. Scores on the Social Dominance factor were found to be very strongly correlated with the androgyny scores of both males and females. The BSRI appears to be heterogeneous in content, and the structure of sex role self-descriptors is more complex than the conception of independent “masculine” and “feminine” dimensions. The analysis of the BSRI according to specific content factors may provide explanations for some of the findings of research on psychological androgyny.

scholarly journals Young chicks quickly lose their spontaneous preference to aggregate with females

2020 ◽  
Author(s):  
Virginia Pallante ◽  
Daniele Rucco ◽  
Elisabetta Versace
Keyword(s):  
Sex Discrimination ◽  
Phasianus Colchicus ◽  
Same Sex ◽  
Experimental Protocol ◽  
Male And Female ◽  
Sex Preference ◽  
Initial Preference ◽  
The Social ◽  
Males And Females ◽  
Young Chicks

AbstractIt is not clear when and how animals start to discriminate between male and female conspecifics and how this distinction drives their social behaviour. A recent study on pheasants found that one-week-old chicks (Phasianus colchicus) preferentially aggregated with same-sex peers and this trend became more pronounced through development, suggesting that sexual segregation increases during ontogeny. However, it remains unclear whether this ability depends on experience or develops spontaneously. Using a similar experimental protocol, we investigated whether sex discrimination is present at birth in domestic chickens (Gallus gallus) by testing the aggregation preferences of young chicks with clutch mates. We measured the amount of time spent close to male and female conspecifics in visually inexperienced chicks. Soon after hatching, both males and females preferentially aggregated with females. To clarify whether the experience with conspecifics modifies the initial preference for females we used an imprinting procedure. We exposed chicks to conspecifics of the same sex, different sex or both sexes for three days and then tested their preferences to aggregate with males or females. No sex preference was observed after three days of imprinting exposure. The disappearance of the initial sex preference shows that, although chicks can discriminate between conspecifics of different sex, sex segregation does not influence aggregation in the first week of life. We suggest that the absence of sexual assortment in the first week of age can enhance the social cohesion of the flock.

scholarly journals Mannitol ingestion causes concentration-dependent, sex-specific mortality in adults of the fruit fly (Drosophila melanogaster)

2019 ◽  
Author(s):  
Katherine Fiocca ◽  
Meghan Barrett ◽  
Edward A. Waddell ◽  
Cheyenne McNair ◽  
Sean O’Donnell ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Fruit Fly ◽  
Reproductive Costs ◽  
Female Mortality ◽  
Male Mortality ◽  
Single Sex ◽  
Specific Effects ◽  
Energy Needs ◽  
Specific Mortality ◽  
Males And Females

AbstractMannitol, a sugar alcohol used in commercial food products, induced sex-specific mortality in the fruit flyDrosophila melanogasterwhen ingested at a single concentration (1M), and female mortality was greater than male mortality. We hypothesized that sex differences in energy needs, related to reproductive costs, contribute to increased mortality in females compared to males. To test for the effects of reproductive costs, we compared longevity to 21 days of actively mating and non-mating flies fed various concentrations of mannitol. We also asked whether mannitol-induced mortality was concentration-dependent for both males and females, and if mannitol’s sex-specific effects were consistent across concentrations. Females and males both showed concentration-dependent increases in mortality, but female mortality was consistently higher at all concentrations above 0.75M. Fly longevity to 21 days decreased further for both sexes when housed in mixed sex vials (as compared to single sex vials), suggesting the increased energetic demands of reproduction for both sexes may increase ingestion of mannitol. Mannitol fed to larvae did not alter emerging adult sex ratios, suggesting that sex-specific mortality due to mannitol occurs only in adults.

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