Population, sex ratios and Development in Greenland

Abstract During the 20th century, Greenland society experienced a dramatic transformation from scattered settlements based on hunting, with mostly turf dwellings, to an urbanizing post-industrial economy. This transformation compressed socioeconomic development that took centuries to millennia elsewhere into a few generations. The incomplete demographic transition that accompanied this development broadly followed the classical pattern, but with distinctive variations relating to Greenland\u27s Arctic environment, sparse population, and historical interactions between two cultures: an indigenous Inuit majority and an influential Danish minority. One heritage from Danish colonial administration, and continued more recently under Greenland Home Rule, has been the maintenance of population statistics. Time series of demographic indicators, some going back into the 18th century, provide a uniquely detailed view of the rapid hunting-to-post-industrial transition. Changing sex ratios-an early excess of females, shifting more recently to an excess of males-reflect differential impacts of social, economic, and technological developments

Skewed sex ratio in an estuarine lobster (Homarus americanus) population

A total of 19,485 lobsters were caught sites in the estuarine and coastal waters of New Hampshire from 1989 to 1992, and their size and sex were determined. The sex ratio of lobsters caught farthest from the coast, in Great Bay, was heavily skewed in favor in males. Sex ratios in other estuarine and river sites were also skewed toward males, and there was a tendency for the number of males per female to decline as one moved down the estuary toward the coast, where the sex ratio was nearly 1:1. The single offshore site was dominated by females, with about 0.6 males for each female. There were also seasonal trends in the sex ratios in the upper estuarine sties, where the number of males per female tended to decline from summer through autumn. In general, differences in the sex ratios between sites were those of primarily adult lobsters larger than 80 mm carapace length (CL). At all sites, the sex ratio of lobsters smaller than this size was close to 1:1, whereas in the upper estuary the mean sex ratio of lobsters greater than 80 mm CL was more than 14:1. These data, in conjunction with seasonal variations of sex ratios, suggest that differential movements of adult male and female lobsters is the primary cause of skewed sex ratios in the Great Bay Estuary

Extraordinary Sex Ratios: Cultural Effects on Ecological Consequences

We model sex-structured population dynamics to analyze pairwise competition between groups differing both genetically and culturally. A sex-ratio allele is expressed in the heterogametic sex only, so that assumptions of Fisher's analysis do not apply. Sex-ratio evolution drives cultural evolution of a group-associated trait governing mortality in the homogametic sex. The two-sex dynamics under resource limitation induces a strong Allee effect that depends on both sex ratio and cultural trait values. We describe the resulting threshold, separating extinction from positive growth, as a function of female and male densities. When initial conditions avoid extinction due to the Allee effect, different sex ratios cannot coexist; in our model, greater female allocation always invades and excludes a lesser allocation. But the culturally transmitted trait interacts with the sex ratio to determine the ecological consequences of successful invasion. The invading female allocation may permit population persistence at self-regulated equilibrium. For this case, the resident culture may be excluded, or may coexist with the invader culture. That is, a single sex-ratio allele in females and a cultural dimorphism in male mortality can persist; a low-mortality resident trait is maintained by father-to-son cultural transmission. Otherwise, the successfully invading female allocation excludes the resident allele and culture, and then drives the population to extinction via a shortage of males. Finally, we show that the results obtained under homogeneous mixing hold, with caveats, in a spatially explicit model with local mating and diffusive dispersal in both sexes.Comment: final version, reflecting changes in response to referees' comment

Working Late: Do Workplace Sex Ratios Affect Partnership Formation and Dissolution?

In this paper, I analyse the association between workplace sex ratios and partnership formation and dissolution. I find that the risk of dissolution increases with the fraction of coworkers of the opposite sex at both the female and male workplace. On the other hand, workplace sex ratios are not important for the overall transition rate from singlehood to partnership. The results suggest that the workplace constitutes a more important marriage market segment for individuals who are already in a partnership presumably due to higher search cost for (alternative) partners in general.partnership formation; dissolution; workplace sex ratios

A Multinomial Model of Fertility Choice and Offspring Sex-Ratios in India

Fertility decline in developing countries may have unexpected demographic consequences. Although lower fertility improves nutrition, health, and human capital investments for surviving children, little is known about the relationship between fertility outcomes and female-male offspring sex-ratios. Particularly in countries with a cultural preference for sons, like India and China, fertility decline may deteriorate the already imbalanced sex-ratios. We use the fertility histories of over 90,000 Indian women in the Second National Family and Health Survey to investigate the relationship between fertility choices and offspring sex-ratios in India. Both within- and between-family-size differences in offspring sex-ratios are examined. Our analysis reveals three main findings. First, within-family-size differences show that for our reference household (i.e. non-low-caste Hindus), parental education reduces anti-female bias in survival in large families (three or more children households) but plays no role in small families (one or two children households). While a higher standard of living worsens anti-female bias in survival in both large and small families, it does so to a greater extent in small families. Small families that own land also have lower offspring sex-ratios compared to landless households. Second, between-family-size differences indicate an `intensification' effect, whereby small families have dramatically lower offspring sex-ratios than large families. The intensification effect is greatest for Sikh and non-low-caste Hindu households, followed by low-caste Hindu and Christian households, but does not exist for Muslims. Third, while maternal education and urban residence weaken the intensification effect, paternal education, a higher standard of living, and land ownership strengthen it. Our results suggest that fertility decline, together with economic growth, may worsen India's already imbalanced sex-ratios. Thus, much needed fertility control policies must be supplemented with programs that counter offspring sex-selection in favor of sons. Policies that seek to eradicate son preference by making daughters more economically attractive to parents as well as those that imbibe more gender-equal attitudes within individuals are critically needed as economic growth generates higher levels of education and wealth in India.Female Disadvantage, Mortality, Son Preference, Fertility, India

Sex Ratios, Divorce Laws and the Marriage Market

We show how an interaction between the skewness of the sex ratio and the jump in divorce rates after a liberalization in divorce laws can obtain in a model of marriage market matching with non-transferable utility. This model is partly motivated by a significant cross-country correlation between these two variables. We also find that men’s hopes or fears about women’s marriage market odds are self-confirming under mutual consent, resulting in multiple equilibria. The multiplicity vanishes with a more skewed sex ratio or a liberalization of divorce laws. Our work sheds some light on the possible implications of divorce liberalization and pro-marriage policies.Divorce, sex ratios, marriage, skewness, matching, non-transferable utility.

Environment and sex ratios among alaska natives: An historical perspective

Human-environment interactions can affect the sex ratios of resource-dependent societies in a variety of ways. Historical and contemporary data on Alaska Native populations illustrate such effects. Some eighteenth and early nineteenth century observers noted an excess of females, which they attributed to high mortality among hunters. Population counts in the later nineteenth century and well into the twentieth found instead an excess of men in many communities. Female infanticide was credited as the explanation: since family survival depended upon hunting success, males were more valued. Although infanticide explanations for the excess of males have been widely believed, available demographic data point to something else: higher adult female mortality. Finally, in the postwar years, the importance of mortality differentials seems to have faded-and also changed direction. Female outmigration from villages accounts for much of the gender imbalance among Native populations today. Natural-resource development, particularly North Slope oil, indirectly drives this migration. In Alaska\u27s transcultural communities, the present gender imbalances raise issues of individual and cultural survival

Why Are More Boys Born During War? - Evidence from Germany at Mid Century

In belligerent countries, male-to-female sex ratios at birth increased during and shortly after the two world wars. These rises still defy explanation. Several causes have been suggested (but not tested) in the literature. Many of these causes are proximate in nature, reflecting behavioral responses to the dramatically changed marriage market conditions for women and men that were induced by war-related declines in adult sex ratios. Based on county-level census data for the German state of Bavaria in the vicinity and aftermath of World War II, we explore the reduced-form relationship between changes in adult and off spring sex ratios. Our results suggest that war-induced shortfalls of men significantly increased the percentage of boys among newborns.World War II, adult sex ratio, sex ratio at birth