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Results for “Nuptiality”

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PubMedDate not supplied

[Nuptiality, fertility, and the family. The paradox of nuptiality trends and fertility in Spain].

"The purpose of this article is to reexamine the present significance of nuptiality from a demographic standpoint and its influence on fertility and the formation of the family in Western society, and in Spain in particular." The authors suggest that the demographic trends occurring in economically advanced countries are without precedent and represent a clear break with previous demographic experience. (SUMMARY IN ENG)

Demography↗

PubMed2004

Male-male competition and nuptial-colour displacement as a diversifying force in Lake Victoria cichlid fishes.

We propose a new mechanism for diversification of male nuptial-colour patterns in the rapidly speciating cichlid fishes of Lake Victoria. Sympatric closely related species often display nuptial colours at opposite ends of the spectrum with males either blue or yellow to red. Colour polymorphisms within single populations are common too. We propose that competition between males for breeding sites promotes such colour diversification, and thereby speciation. We hypothesize that male aggression is primarily directed towards males of the common colour, and that rare colour morphs enjoy a negatively frequency-dependent fitness advantage. We test our hypothesis with a large dataset on the distributions and nuptial colorations of 52 species on 47 habitat islands in Lake Victoria, and with a smaller dataset on the within-spawning-site distributions of males with different coloration. We report that territories of males of the same colour are negatively associated on the spawning site, and that the distribution of closely related species over habitat islands is determined by nuptial coloration in the fashion predicted by our hypothesis. Whereas among unrelated species those with similar nuptial colour are positively associated, among closely related species those with similar colour are negatively associated and those with different colour are positively associated. This implies that negatively frequency-dependent selection on nuptial coloration among closely related species is a sufficiently strong force to override other effects on species distributions. We suggest that male-male competition is an important and previously neglected agent of diversification among haplochromine cichlid fishes.

Aggression↗

PubMed1979

Factors associated with ex-nuptial birth.

The paper examines the background to 210 live exnuptial births studied in the first phase of the Christ-church Child Development Study. The results show: 1. That nearly half of the children had been conceived within cohabiting situations. 2. That nearly one in five ex-nuptial children was the result of a planned pregnancy. 3. Maternal reactions to the birth and pregnancy varied with the mother's situation: cohabiting mothers reported considerably less adverse reaction to the birth than did non-cohabiting mothers. 4. Overall, mothers of ex-nuptial children had a fairly sophisticated appreciation of contraceptive methods. 5. One quarter of unplanned ex-nuptial pregnancies were the result of contraceptive failure and three-quarters were the result of contraceptive non-usage. 6. In common with previous findings for nuptial pregnancies, about 35 percent of unplanned ex-nuptial pregnancies were ascribed to a breakdown in the mother's pattern of usage of the contraceptive pill.

Adolescent↗

PubMed1995

[Nuptiality of single persons in the Czech Republic, past and present].

"Nuptiality...of single persons in the Czech Republic can be distributed into 3 stages. During the first one specified by the period since World War II until the beginning of the sixties nuptiality...developed in accordance with the European trends.... The second stage started in the sixties and was completed in 1989.... In this stage...the Czech Republic's population started its differentiation of nuptial behaviour as compared to a series of developed countries, where at the turn of the seventies the intensity of single persons' nuptiality has declined while the average age at the first marriage has been increasing. Since 1992 the third stage has appeared in the Czech Republic characterized by declining intensity and growth of marriage age." (SUMMARY IN ENG AND RUS)

Czech Republic↗

PubMedDate not supplied

The role of nuptiality in the demographic transition. The case of Africa: a conceptual essay.

"The focus of analysis is on the direction of change and causes of shifts in age at first marriage among women in the demographic transition in Africa. The principal goal of the analysis is to assess and verify the paramount, determining role of nuptiality in affecting demographic transformation, especially in fertility. The findings confirm that in societies with early/universal marital patterns, initial demographic change is confined to nuptiality while fertility may be rising for decades. Two sets of causes of the shift to a later nuptiality pattern are examined. One refers to the role of nuptiality in premodern societies. The other considers: the built-in mechanism in the rate of population growth; diminishing frequency of polygyny; expansion in education; and increasing employment of women in non-traditional occupations." (SUMMARY IN ITA AND FRE)

Africa↗

PubMed2003

Divergent selection during speciation of Lake Malawi cichlid fishes inferred from parallel radiations in nuptial coloration.

Repeated evolution of the same phenotypic difference during independent episodes of speciation is strong evidence for selection during speciation. More than 1,000 species of cichlids, >10% of the world's freshwater fish species, have arisen within the past million years in Lakes Malawi and Victoria in eastern Africa. Many pairs of closely related sympatric species differ in their nuptial coloration in very similar ways. Nuptial coloration is important in their mate choice, and speciation by sexual selection on genetically or ecologically constrained variation in nuptial coloration had been proposed, which would repeatedly produce similar nuptial types in different populations, a prediction that was difficult to test in the absence of population-level phylogenies. We measured genetic similarity between individuals within and between populations, species, and lake regions by typing 59 individuals at >2,000 polymorphic genetic loci. From these data, we reconstructed, to our knowledge, the first larger species level phylogeny for the most diverse group of Lake Malawi cichlids. We used the genetic and phylogenetic data to test the divergent selection scenario against colonization, character displacement, and hybridization scenarios that could also explain diverse communities. Diversity has arisen by replicated radiations into the same color types, resulting in phenotypically very different, yet closely related, species within and phenotypically highly similar yet unrelated sets of species between regions, which is consistent with divergent selection during speciation and is inconsistent with colonization and character displacement models.

Africa, Eastern↗

PubMed2002

Nuptial gifts of male spiders function as sensory traps.

While nuptial food gifts come in various forms in arthropods, their evolutionary origins are unclear. A previous study on insects has shown that such gifts may arise as a sensory trap that exploits a female's underlying motivation to feed. Here I present independent evidence of a sensory trap in spiders. In certain visually oriented spiders, I suggest that males initially exploit the maternal care instinct by producing a nuptial gift that closely resembles the female egg sac. Males of the spider Pisaura mirabilis cover their prey gift with a silk layer, transforming it into a white round object. In a laboratory experiment I tested whether the colour of the gift affected the rate that females accepted males displaying their gifts. I found that the brighter and the more alike the nuptial gift to a female's egg sac, the faster the female responded by grabbing the gift. My results support the hypothesis that the nuptial gift in P. mirabilis works as a sensory trap.

Animals↗

PubMed1986

Occupations, migration, sex ratios, and nuptiality in nineteenth century English communities: a model of relationships.

Two effects of occupational structure on nuptiality levels are examined: a direct functional effect related to the influence of socioeconomic characteristics on the feasibility and desirability of marriage, and an indirect structural effect related to nuptiality levels via sex selective migration patterns and population sex ratios. Our analysis shows that nuptiality levels in nineteenth century English and Welsh districts were responsive to occupational variation and that both direct and indirect effects were significant. Our results suggest that socioeconomic factors, often overlooked in favor of cultural explanation, must be considered in the analysis of nuptiality.

Emigration and Immigration↗

PubMed1988

Determinants of short-term fluctuations in nuptiality in Sweden, 1751-1913: application of multivariate ARIMA models.

"This study examines the determinants of short-term fluctuations in nuptiality in Sweden from 1751 to 1913, using ARIMA [Auto Regressive Integrated Moving-Average] models.... The following general patterns prevailed throughout the period 1751-1913: both better economic conditions (good harvests and lower rye prices) and higher mortality (leading to more remarriages, and enabling first marriages through inheritance) were followed by higher nuptiality. In addition, emigration of single persons after 1850 was inversely related to nuptiality." (SUMMARY IN FRE)

Agriculture↗

PubMed1983

A stochastic diffusion model of the time path of nuptiality.

"The time path of nuptiality is approximated by means of the log normal diffusion process. The drift coefficient is estimated by the method of maximum likelihood. Swedish and Canadian data on nuptiality have been utilised to illustrate the model. A piece-wise fitting of the log-normal model to the Swedish data reveals that the drift coefficient is changing over time. The use of mixing distribution is suggested to remedy this problem. On the whole the Hajnal theory of nuptiality transition is supported. It is also seen that the Hajnal transition is one in a series of transitions."

Americas↗

PubMed2003

The effects of anti-androgenic and estrogenic disrupting contaminants on breeding gland (nuptial pad) morphology, plasma testosterone levels, and plasma vitellogenin levels in male Xenopus laevis (African clawed frog).

Nuptial pads are areas, digits, and forearm characterized by epidermal keratin hooks and dermal breeding glands opening on the epidermis surface in male frogs. The presence of the epidermal hooks and secretory activity of the breeding glands are androgen-dependent and considered functioning during mating. Chemical pollutants released into the aquatic environment by humans are suspected of disrupting the normal hormonal pathways and functioning. Among the best known of these endocrine-disrupting contaminants (EDCs) are compounds that mimic the steroid 17beta-estradiol. However, recently specific anti-androgenic activity by certain EDCs, including DDE and several fungicides, have been shown in mammalian studies. The African clawed frog, Xenopus laevis, has been proposed as an ideal species to be used as a model system for screening of endocrine disruptors. In this study we employed a newly developed ELISA for the measurement of plasma vitellogenin (VTG), normally produced in the liver of females under the influence of estrogens but also in males when exposed to exogenous estrogens. Furthermore, we investigated the potential of breeding (nuptial) gland activity to be employed as a biomarker system for screening for anti-androgenic activity by certain EDCs. Our results indicate that the pharmaceutic anti-androgen flutamide did significantly (p < 0.05) effect the androgen-dependent breeding (nuptial) glands and plasma testosterone concentrations in male X. laevis. Our results further confirm that the dicarboximide fungicide vinclozolin mimics the anti-androgenic action of flutamide. Vinclozolin, however, did not significantly effect the plasma testosterone concentration. Results also confirm the ability of 17beta-estradiol to stimulate production and release of VTG in the liver of male X. laevis, although we could not confirm the in vivo induction of VTG by estrogenic mimics octylphenol and nonylphenol. Although more dose-response research is needed, this preliminary study confirms the potential of VTG production and breeding gland activity as biomarkers to screen chemicals and environmental samples for estrogenic and anti-androgenic activity using X. laevis males.

Androgen Antagonists↗

PubMed2005

The energetics of trading nuptial gifts for copulations in katydids.

During copulation, male Isophya kraussi transfer a large nuptial gift to females. In this study, we hypothesized that the energy content of spermatophores should meet the energy requirements of both body maintenance and egg production of females. We measured the field metabolic rate of male and female I. kraussi using the doubly labeled water method and the energy content of spermatophores and male bodies with microbomb calorimetry. The energy content of male nuptial gifts averaged 0.66+/-0.09 kJ, approximately 20% of the total body energy content of male I. kraussi (3.24+/-0.26 kJ). Field metabolic rates averaged 0.41+/-0.17 kJ d(-1) (n = 8) for males and 0.30+/-0.15 kJ d(-1) (n = 5) for female I. kraussi. Thus, the energy content of spermatophores exceeded the daily energy requirements of existence in male I. kraussi. A single nuptial gift provides for all energy requirements of females for 1 or 2 d, depending on their activity, egg production, and ambient temperature. Because the shortest known remating interval of female katydids varies between 1 and 3 d, female I. kraussi could theoretically exist exclusively on spermatophores to meet their nutritional requirements.

Animals↗

PubMed2002

Nuptial gifts and the evolution of male body size.

In many insect systems, males donate nuptial gifts to insure an effective copulation or as a form of paternal investment. However, if gift magnitude is both body size-limited and positively related to fitness, then the opportunity exists for the gift to promote the evolution of large male size. In the striped ground cricket, Allonemobius socius, males transfer a body size-limited, somatic nuptial gift that is comprised primarily of hemolymph. To address the implications of this gift on male size evolution, we quantified the intensity and direction of natural (fecundity) and sexual (mating success) selection over multiple generations. We found that male size was under strong positive sexual selection throughout the breeding season. This pattern of selection was similar in successive generations spanning multiple years. Male size was also under strong natural selection, with the largest males siring the most offspring. However, multivariate selection gradients indicated that gift size, and not male size, was the best predictor of female fecundity. In other words, direct fecundity selection for larger gifts placed indirect positive selection on male body size, supporting the hypothesis that nuptial gifts can influence the evolution of male body size in this system. Although female size was also under strong selection due to a size related fecundity advantage, it did not exceed selection on male size. The implications of these results with regard to the maintenance of the female-biased size dimorphic system are discussed.

Analysis of Variance↗

PubMed2005

Chromatic interaction between egg pigmentation and skin chromatophores in the nuptial coloration of female two-spotted gobies.

In two-spotted gobies (Gobiusculus flavescens Fabricius 1779), females develop an orange belly as they approach sexual maturity. Bright belly coloration is preferred by males and has been suggested to act as a female ornament. This coloration is unusual in that it originates partly from pigmentation of the abdominal skin but also from strongly pigmented gonads directly visible through the skin. In addition, females have been observed to temporarily become more colourful during courtship and competition. To understand how gonad and skin pigmentation interact in this nuptial coloration, the potential for colour modification via regulation of skin chromatophores was investigated. Noradrenaline caused aggregation of chromatophore pigment and was used to experimentally reduce the contribution of skin chromatophores to the nuptial coloration. Chromatophore pigment aggregation caused bellies to become less colourful and abdominal skin biopsies to become less colourful and more transparent. There was a strong positive relationship between belly coloration and the coloration of the underlying gonads. This shows that belly coloration honestly reflects egg pigmentation, mainly because the transparency of the abdominal skin allows other fish to see the gonads directly. Interestingly, when noradrenaline caused pigment to aggregate and thereby increased the transparency of the skin, the relationship between belly and gonad coloration weakened. We conclude that female G. flavescens have a potential to use skin chromatophores to rapidly alter their nuptial coloration, thereby affecting the efficacy with which information about gonad coloration is conveyed.

Animals↗

PubMed1997

Laboratory observations of nuptial flights of the ant Polyrhachis laboriosa.

Ethology of Polyrhachis laboriosa, an ant species from equatorial Africa, is little known. No field observation of a nuptial flight of these ants was ever made. We describe two nuptial flights observed in a laboratory colony of P. laboriosa at a 3 days interval. They both occurred in the morning while the nest was kept in near darkness (less than 2 lux of daylight). Flying activity of the alates was suppressed within 1 h by their exposure to daylight of about 140 lux, and within several minutes by their exposure to a lamp emitting white light of 3,000 lux and acting as a source of heat. On the day following the first flight the alates and the workers showed exceptionally high level of mutual grooming. The alates, in particular the males, were transported by workers to the brood chambers whenever they strayed outside and after the nuptial flights.

Animals↗

PubMed1985

Nuptiality models and the two-sex problem in national population forecasts.

"This paper describes the two-sex problem in nuptiality models, focussing on applications in national population forecasts. Requirements for a realistic two-sex marriage model are mentioned, together with additional considerations important in the context of official forecasts. Recent nuptiality models violate the requirements to a certain extent and/or do not meet the additional considerations. A new model, used in the 1980-based population forecasts of the Netherlands compiled by the Netherlands' Central Bureau of Statistics, is described." (summary in FRE)

Demography↗

PubMed1989

Nuptiality and fertility in the Dominican Republic.

Women in marital unions had more live births than those in consensual unions. The relationship between cumulative fertility and the number of fertile sexual unions is positive for the early childbearing years and negative for the later ones. There is no consistent pattern of relationship between fertility and the sociocultural independent variables for different subgroups according to nuptiality pattern. The relationship between fertility and nuptiality in the Dominican Republic is consistent with that for the Caribbean region.

Adolescent↗

PubMed1982

[The nuptiality model in the 1980-based population forecasts].

"This article describes the nuptiality model that was used in the 1980-based population forecasts of the Netherlands, released by the Netherlands Central Bureau of Statistics...in December 1981." Particular attention is paid to the need for a realistic two-sex marriage model. A model is presented that the author suggests is an improvement on the British model on which it is based, in that it uses originally specified one-sex nuptiality rates, which are adjusted in order to achieve consistency. (summary in ENG)

Developed Countries↗