scholarly journals Causes and consequences of adult sex ratio imbalance in a historical U.S. population

2017 ◽  
Vol 372 (1729) ◽  
pp. 20160314 ◽  
Author(s):  
Ryan Schacht ◽  
Ken R. Smith
Keyword(s):  
Biological Sciences ◽  
Sex Ratio ◽  
Life History Traits ◽  
Male Mating ◽  
Age At First Birth ◽  
The Social ◽  
Adult Sex Ratio ◽  
Sex Ratio Imbalance ◽  
Animal Societies

The responsiveness of individuals to partner availability has been well-documented across the literature. However, there is disagreement regarding the direction of the consequences of sex ratio imbalance. Specifically, does an excess of males or females promote male–male mating competition? In an attempt to clarify the role of the adult sex ratio (ASR) on behaviour, here we evaluate both competing and complimentary expectations derived from theory across the social and biological sciences. We use data drawn from a historical, nineteenth century population in North America and target several life-history traits thought to be affected by partner availability: age at first birth, relationship status, completed fertility and longevity. Furthermore, we assess the role of various contributors to a population's ASR. We find that both the contributors to and consequences of sex ratio imbalance vary over time. Our results largely support predictions of greater male pairbond commitment and lesser male mating effort, as well as elevated bargaining power of women in response to female scarcity. After reviewing our findings, and others from across the literature, we highlight the need to adjust predictions in response to ASR imbalance by the: (i) culturally mediated mating arena, (ii) variable role of demographic inputs across time and place, (iii) constraints to behavioural outcomes across populations, and (iv) ability and accuracy of individuals to assess partner availability. This article is part of the themed issue ‘Adult sex ratios and reproductive strategies: a critical re-examination of sex differences in human and animal societies’.

scholarly journals Sex ratio effects on reproductive strategies in humans

2015 ◽  
Vol 2 (1) ◽  
pp. 140402 ◽  
Author(s):  
Ryan Schacht ◽  
Monique Borgerhoff Mulder
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Ethnic Group ◽  
Reproductive Strategies ◽  
Situational Factors ◽  
Male Mating ◽  
Mating Effort ◽  
Short Term ◽  
Adult Sex Ratio ◽  
Using Data

Characterizations of coy females and ardent males are rooted in models of sexual selection that are increasingly outdated. Evolutionary feedbacks can strongly influence the sex roles and subsequent patterns of sex differentiated investment in mating effort, with a key component being the adult sex ratio (ASR). Using data from eight Makushi communities of southern Guyana, characterized by varying ASRs contingent on migration, we show that even within a single ethnic group, male mating effort varies in predictable ways with the ASR. At male-biased sex ratios, men's and women's investment in mating effort are indistinguishable; only when men are in the minority are they more inclined towards short-term, low investment relationships than women. Our results support the behavioural ecological tenet that reproductive strategies are predictable and contingent on varying situational factors.

Worlds in Collision: Owen and Huxley on the Brain

1997 ◽  
Vol 10 (2) ◽  
pp. 343-365 ◽  
Author(s):  
C.U.M. Smith
Keyword(s):  
Biological Sciences ◽  
Social Context ◽  
Scientific Advance ◽  
Societal Factors ◽  
The Social ◽  
Philosophical Intuition ◽  
Biological World ◽  
Richard Owen ◽  
The Brain

The ArgumentThis paper makes use of the 1860 clash between T. H. Huxley and Richard Owen to examine the role of social context in scientific advance in the biological sciences. It shows how the social context of nineteenth-century England first favored the Coleridge-Owenite interpretation of the biological world and then, at mid-century and subsequently, allowed the Darwin-Huxley interpretation to win through. It emphasizes the complexity of the clash. Professional, personal, and generational agendas as well as scientific theory and fundamental philosophical intuition were at stake. The history, ultimately, provides a useful instance of Schutz ‘s and Scheler ‘s concept of societal factors controlling and selecting between flows of idealfactoren. Although Huxley is conventionally regarded as the victor I conclude by suggesting that the issue is not yet closed and that profound philosophical issues remain unresolved.

scholarly journals Spatiotemporal variation in the adult sex ratio, male aggregation, and movement of two tropical cloud forest dung beetles

2021 ◽  
Author(s):  
Julliana Barretto ◽  
Martha L Baena ◽  
Israel Huesca Domínguez ◽  
Federico Escobar
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Life History Traits ◽  
Cloud Forest ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Dung Beetle ◽  
Adult Sex Ratio ◽  
The Face ◽  
Male Aggregation

Abstract While theory suggests that at conception the sex ratio should be balanced (1:1), this can be variable across space and time in wild populations. Currently, studies of the environmental factors that regulate adult sex ratio (ASR) in species with different life-history traits are scarce. Using capture-recapture over a year, we analyzed the influence of habitat type (forest and non-forest) and season (rainy and dry) on variation in ASR, male aggregation and the trajectory movement of two dung beetle species with different life-history traits: Deltochilum mexicanum (a hornless roller species) and Dichotomius satanas (a tunneler species with horns on its head and thorax). We found opposite tendencies. The D. mexicanum population tends to be female-biased, but the population of D. satanas tends to be predominantly male, and observed values were not related to habitat type or season. However, the 95% confidence intervals estimated were highly variable between seasons depending on habitat. On examining the monthly variation in ASR for both habitats, we found that it depends on the species. In addition, male aggregation differed between species depending on habitat type and season, and species movement patterns were closely related to their habitat preferences. Based on our results, we argue that comparative population studies of species with different life-history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.

The Threat of Genes: A Comment on Evan Charney's “Genes and Ideologies”

2008 ◽  
Vol 6 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Rebecca J. Hannagan ◽  
Peter K. Hatemi
Keyword(s):  
Social Sciences ◽  
Biological Sciences ◽  
Political Science ◽  
Political Behavior ◽  
American Political Science Review ◽  
Theoretical Models ◽  
Science Review ◽  
The Social ◽  
American Political Science

In his essay, “Genes and Ideologies,” Evan Charney wrangles with the question of the role of genes in the formation of political attitudes via a critique of Alford, Funk, and Hibbing's 2005 American Political Science Review article. Although critical evaluations are necessary, his essay falls short of what is required of a scientific critique on both empirical and theoretical grounds. We offer a comment on his essay and further contend that it is naïve to proceed on the assumption that a barrier exists between the biological and social sciences, such that the biological sciences have nothing to offer the social sciences. If we look beyond our discipline's current theoretical models we may find a more thorough, and not just competing, explanation of political behavior.

scholarly journals Shared decision-making allows subordinates to lead when dominants monopolize resources

2020 ◽  
Vol 6 (48) ◽  
pp. eaba5881
Author(s):  
Danai Papageorgiou ◽  
Damien R. Farine
Keyword(s):  
Decision Making ◽  
Shared Decision Making ◽  
Dominance Hierarchy ◽  
Social Groups ◽  
Decision Makers ◽  
Shared Decision ◽  
Intragroup Conflict ◽  
The Social ◽  
Animal Societies

The concepts of leadership and dominance are often conflated, with individuals high in the social hierarchy assumed to be decision-makers. Dominants can exclusively benefit from monopolizing food resources and, therefore, induce an intragroup conflict when leading their group to these resources. We demonstrate that shared decision-making reduces such conflicts by studying movement initiations of wild vulturine guineafowl, a species that forms large, stable social groups with a steep dominance hierarchy. When dominant individuals displace subordinates from monopolizable food patches, the excluded subordinates subsequently initiate collective movement. The dominants then abandon the patch to follow the direction of subordinates, contrasting with nonmonopolizable resources where no individuals are excluded, and dominant individuals contribute extensively to group decisions. Our results demonstrate the role of shared decision-making in maintaining the balance of influence within animal societies.

scholarly journals Agricultural Economics Research and The Experiment Station System

1987 ◽  
Vol 19 (2) ◽  
pp. 195-201
Author(s):  
David L. Debertin ◽  
Garnett L. Bradford
Keyword(s):  
Social Sciences ◽  
Biological Sciences ◽  
Agricultural Economics ◽  
Land Grant University ◽  
University System ◽  
Experiment Station ◽  
The Social ◽  
Colleges Of Agriculture ◽  
Economics Research

AbstractThis paper discusses the role of agricultural economics research within the land-grant university system. Fundamental differences between research in the biological sciences and the social sciences are delineated. Implications of these differences for experiment station research programs are discussed. Recommendations are made which have potential for enhancing the role of agricultural economics within colleges of agriculture.

scholarly journals Dispersion and site fidelity in a tent-roosting population of the short-nosed fruit bat (Cynopterus sphinx) in southern India

2000 ◽  
Vol 16 (1) ◽  
pp. 117-131 ◽  
Author(s):  
Jay F. Storz ◽  
J. Balasingh ◽  
P. Thiruchenthil Nathan ◽  
K. Emmanuel ◽  
Thomas H. Kunz
Keyword(s):  
Sex Ratio ◽  
Site Fidelity ◽  
Local Population ◽  
Southern India ◽  
Male Mating ◽  
Adult Males ◽  
Single Male ◽  
Fruit Bat ◽  
Cynopterus Sphinx ◽  
Adult Sex Ratio

Patterns of dispersion and site fidelity were investigated in a tent-roosting population of the short-nosed fruit bat, Cynopterus sphinx (Megachiroptera), in southern India. A local population of C. sphinx occupied diurnal roosts in a variable subset of 45 stem tents constructed within the dense foliage of mast trees (Polyalthia longifolia). Individually marked tent-roosting bats were visually censused over the course of a 38-d interval spanning the postpartum oestrus period. On any given day, 33.3–85.7% (mean = 60.8%, SD = 14.2) of adult males roosted singly, with the remainder holding harems of 1–10 breeding females (mean = 3.01, SD = 0.79). Average harem sex ratio was 2.8-fold higher than the adult sex ratio of the total tent-roosting population within the study area, indicating the potential for a high variance in male mating success within a single breeding season. Bats of both sexes typically occupied one primary tent, interspersed with shorter periods of residency in alternate tents. Males exhibited a significantly higher degree of roost fidelity than females. Some females roosted sequentially with different males and with different combinations of females, whereas others remained continuously associated with a single male and/or particular female roostmates over the duration of the census period. There were no statistically significant relationships between physical characteristics of tents and rates of occupancy by males or females. Intermittent transfers by females between groups suggest that the defence of diurnal roosts by males represents a more profitable mating strategy than the direct defence of compositionally labile female groups.

Social Representations and Commitment

2018 ◽  
Vol 23 (3) ◽  
pp. 233-249 ◽  
Author(s):  
Eric Bonetto ◽  
Fabien Girandola ◽  
Grégory Lo Monaco
Keyword(s):  
Social Representations ◽  
Social Representation ◽  
Second Line ◽  
Review Of The Literature ◽  
First Line ◽  
Research Perspectives ◽  
The Social ◽  
Bibliographic Search ◽  
English Articles

Abstract. This contribution consists of a critical review of the literature about the articulation of two traditionally separated theoretical fields: social representations and commitment. Besides consulting various works and communications, a bibliographic search was carried out (between February and December, 2016) on various databases using the keywords “commitment” and “social representation,” in the singular and in the plural, in French and in English. Articles published in English or in French, that explicitly made reference to both terms, were included. The relations between commitment and social representations are approached according to two approaches or complementary lines. The first line follows the role of commitment in the representational dynamics: how can commitment transform the representations? This articulation gathers most of the work on the topic. The second line envisages the social representations as determinants of commitment procedures: how can these representations influence the effects of commitment procedures? This literature review will identify unexploited tracks, as well as research perspectives for both areas of research.

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