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Indiscriminate polyandry and male parental effort.

Extrapair paternity involves cooperation between mated females and extrapair males. On the other hand, mated males exhibit a spectrum of anti-cuckolding strategies. Hence, extrapair attributes of diverse species and populations reported in the literature are particular solutions of evolutionary games involving gender-specific cuckolding/anti-cuckolding strategies. Here we use game theoretical methods to study the effect of male paternal effort conserving strategies in situations where females seek extrapair fertilizations (EPF) for reasons of genetic compatibility and/or in pursuit of genetic diversity for their offspring. In such cases, females cannot make a pre-copulatory selection of the optimal genetic partners, and therefore combine promiscuous copulation with the use of in copula and/or post-copulatory selection mechanisms to optimize the genetic endowment of their offspring-indiscriminate polyandry. Our results indicate that, when indiscriminate polygamy is constrained by the availability of extrapair male partners, there are three possible (parameter regime wise) evolutionary stable strategy solutions. (1). All females seek EPF, while all males restrict parental care. (2). All females seek EPF, while all males are unconditionally parental. (3). Females use a combination strategy where pursuit of EPF is mixed-on either a population, or an individual level-with genetic monogamy, while all males use a conditional paternal care strategy, which involves adjusting their parental efforts according to their certainty of paternity.

Animals↗

Evolution of MHC-G in primates: a different kind of molecule for each group of species.

When MHC-G molecules in primates (New World and Old World monkeys, Anthropoids and humans) were compared phylogenetically, very different evolutionary patterns within each species were found; their molecules did not have a straight forward and linear development throughout the postulated evolutionary pathway of primates. The earlier New World monkeys (South America) had relatively more alleles and the polymorphism was placed in the T-cell receptor (TcR), NK receptors and antigen binding sites; MHC-G probably works as a classical class I presenting molecule in these monkeys. MHC-G intron 2 from New World monkeys does not show the typical 23 bp deletion found in all other more recent primate species. Thus, it is possible that MHC-G molecules in New World monkeys belong to a different lineage than the MHC from higher primates. Another early lineage, Eurasian Old World monkeys, shows stop codons at exon 3: MHC-G proteins lacking the alpha2 domain may functionally suffice or otherwise reading-through stop-codon translational mechanisms may exist, as shown for other genes. Orangutans show lower (but significant) polymorphism than New World monkeys at NK, TcR and antigen binding regions; gorilla and chimpanzee show very low polymorphism. Humans only show three different HLA-G proteins with changes not affecting NK, TcR or antigen binding sites. It is observed that the more exposed the mother to allogeneic fetuses (polygamy), the less polymorphic HLA-G is observed within a given species. The data are concordant with the postulated immune inhibitory function for MHC-G in Old World monkeys, anthropoids and humans both at placental and inflammatory level.

Amino Acid Sequence↗

AIDS and cultural practices in Africa: the case of the Tonga (Zambia).

The fight against AIDS in Africa is often presented as a fight against "cultural barriers" that are seen as promoting the spread of the HIV virus. This attitude is based on a long history of Western prejudices about sexuality in Africa, which focus on its exotic aspects only (polygamy, adultery, wife-exchange, circumcision, dry sex, levirate, sexual pollution, sexual cleansing, various beliefs and taboos, etc.). The article argues that those cultural aspects are a wrong target of AIDS prevention programs because they are not incompatible with a safer behavior, and because their eradication would not ensure the protection of people. To fight against them might alienate the people whose cooperation is necessary if one wants to prevent the spread of AIDS. The major problems of AIDS prevention in Africa are not specifically African, but are similar to the problems existing in Europe or America. Therefore, anti-AIDS projects should not fight against one local African culture in order to impose another (Western), but should rather try to make behavior and practises safer in a way that is culturally acceptable to people.

Condoms↗

The effect of a zinc, cobalt and selenium soluble glass bolus on trace element status and semen quality of ram lambs.

Supplemental zinc and selenium were administered to ram lambs grazed on pastures that were not considered to be deficient in either element. The breeding season and polygamy of the ram mean that his requirements for semen production will be relatively large over a short breeding season and this may induce a localised deficiency of zinc and/or selenium, thus resulting in a decrease in semen quality and production.Thirty-three 8-month-old ram lambs were kept at grass and fed a supplement of barley and peas, with ad libitum access to grass silage when grazing became restricted. On day 0, the rams were allocated to two groups by restricted randomisation of live weight. One group each had a zinc, cobalt and selenium soluble glass bolus (Zincosel(R), Telsol) administered with the other group not receiving a bolus to act as a control. Blood samples were taken by jugular venipuncture at day 0 (prior to bolus administration) and at days 23, 44, 65 and 86. Blood samples were analysed for zinc status (plasma zinc concentration) and selenium status (erythrocyte glutathione peroxidase activity). Semen was collected once a week between days 44 and 86, by diversion during a natural mount. Semen quality was assessed by ejaculate volume, spermatocrit, sperm concentration, abnormal morphology, motility, percentage live (negrosin-eosin stain), membrane integrity (hypo-osmotic swelling test (HOS)) and seminal fluid glutathione peroxidase activity and zinc concentration. The bolused lambs had a significantly increased erythrocyte glutathione peroxidase activity (P<0.01) on all samplings after bolusing and had significant increases in motility, proportion of live sperm and proportion of intact membranes indicated by the HOS. The bolused ram lambs had an increased selenium status and apparent improvement in semen membrane quality.

Animals↗

Polygyny, reproductive success and child health in rural Ethiopia: why marry a married man?

This study examines the reproductive success of men and women in rural Ethiopia as a function of their marital status, specifically by comparing polygamously and monogamously married individuals. In line with predictions from evolutionary theory, polygamy is beneficial to male reproductive success (i.e. producing larger numbers of surviving offspring). The success of polygamously married females depends on wife rank: the first wives of polygamous husbands do better than monogamously married women and much better than second or third wives. These effects are mirrored in child nutritional status: the children of second and third wives have lower weight for height. Due to potential, largely unmeasurable differences in marriageability (quality) between individuals, it was not possible to support a model of either resource-holding polygyny combined with female choice or female coercion into unwanted marriages. First wives of polygamously married men marry at a younger age and attract a higher brideprice, suggesting that both the males and females in the marriage are likely to be of higher quality (due to wealth, family status or some other factor such as beauty). Unions that end up monogamous are likely to be between slightly lower quality individuals; and second and third wives, who marry at the oldest ages and attract the lowest brideprice, may be 'making the best of a bad job'. The relatively long gap between first and second marriages may mean that first wives of highly marriageable males can enjoy considerable reproductive success before their husbands marry again.

Adolescent↗

Mating behaviour of Rhytidoponera sp. 12 ants inferred from microsatellite analysis.

In the queenless ponerine ant Rhytidoponera sp. 12, all workers have a spermatheca and functional ovaries and are potentially able to mate and reproduce. Within a colony gamergates may either be full sisters to each other (Type 1 colony), or they may not be full sisters but still be significantly related to each other (Type 2 colony) due to daughter gamergates reproducing in their natal colonies after mating. Despite many studies the mating behaviour of R. sp. 12 has been poorly understood. In this study, we used microsatellite markers to investigate intracolony relatednesses of male mates to the gamergates (bmq) and between male mates (bmm), and mating frequencies and mating patterns, using gamergate DNA and sperm DNA isolated from the spermathecae of gamergates from five colonies. Average bmm and bmq estimates for all five colonies studied were not significantly different from zero, suggesting that on average, within colonies, mating males were unrelated both to each other and to the gamergates. A low frequency (3%) of multiple mating by gamergates was detected. Multiple mating by individual males with sister gamergates within Type 1 colonies was also detected at 3% and could give rise to half-sister nestmate workers. Polygamy in R. sp. 12 might indicate local female-biased operational sex ratios despite the expectation of overall male biases. Our results concur with previous reports that gamergates mate within the colony or nearby, but indicate more diversity in mating patterns than previously indicated for this polygynous ponerine ant species.

Animals↗

The Saradidi, Kenya, rural health development programme: retrospective demographic analysis.

A census was done in Saradidi, Kenya from 1980 to 1982 as part of a community-based health development programme. The population was 42,755 (excluding 39 persons of unknown age or sex); 17.1% were less than five years old, 46.9% were below age 15, 4.7% were age 65 years or older and 19.7% were women in the reproductive years (age 15 to 44 years). The sex ratio was 86 males per 100 females due principally to migration of adult males for work. The mean number of persons per household was 4.0 and the mean village population was 764. The singulate mean age of marriage for men was 27.0 years and for women 19.9 years; 0.8% of adult men had never married. Only 0.1% of women by age 50 had never been married. Men were significantly more likely than women to be married to more than one spouse, divorce and separation was higher among men, and by age 50 about one-third of women were widows. Men had more years of formal education than women and young people of both sexes more than older people; 73.1% of men and 96.1% of women 60 years and more had never attended school. Infant mortality rates estimated indirectly ranged between 139 and 155 by area. A strong association was found between increasing education of the mother and decreased reported mortality of children. The total fertility of 6.2 was high but lower than the national average possibly because of the high rates of polygamy and primary infertility and the long periods of amenorrhoea and breast feeding which occurred after delivery. This area continues to have one of the highest levels of infant and child mortality in Kenya as well as relatively high fertility and a population with a very young age structure. This implies a continued very rapid rate of population growth which will make more difficult in the future the problems of delivering effective health services and overcoming poverty. A vigorous programme directed toward improving health is indicated which must include family planning.

Community Health Services↗

Mental health aspects of Arab-Israeli adolescents from polygamous versus monogamous families.

The authors considered the mental health consequences of polygamy in a sample of 101 Arab Muslim adolescents (19 from polygamous and 82 from monogamous families) at Juarish (Ramla), Israel. The respondents completed the Self-Esteem Scale (SE; M. Rosenberg, 1979), the Brief Symptom Inventory (BSI; L. Derogatis & N. Melsavados, 1983; L. Derogatis & P. Spencer, 1982), and the McMaster Family Assessment Device (FAD; N. B. Epstein, M. N. Baldwin, & D. S. Bishop, 1983). The respondents from polygamous families had lower SE scores, statistically significant higher scores in 2 BSI dimensions, higher scores in all other BSI dimensions, and higher levels of self-reported family dysfunction. The respondents from polygamous families reported lower levels of socioeconomic status, academic achievement, and parental academic attainment. Those variables may have had a more direct impact on mental health than did parental marital status. The data also indicated that perceived family functioning was the best predictor of mental health.

Analysis of Variance↗

Emotional distress and its correlates among Nigerian women in late pregnancy.

A cross-sectional study was carried out in a Teaching Hospital to compare women in late pregnancy and matched controls for emotional distress. Each of the 156 pregnant women was matched with a control and studied to determine the relationship of some obstetric and sociodemographic factors with anxiety and depression. All the subjects were evaluated using the state form of the State-Trait Anxiety Inventory (STAI-state) and the Zung's Self-Rating Depression Scale (SDS), which are standardised instruments for assessing depression and anxiety, respectively. The pregnant women had significantly higher levels of anxiety and higher levels of depression than their non-pregnant controls. Four of the factors evaluated (age, level of education, socio-economic status and parity) were not found to be significantly related to anxiety or depression among the pregnant women. However, four other factors, i.e. polygamy, previous abortions, mode of previous delivery (caesarean section and instrumentally-assisted delivery) and previous puerperal complications had positive and significant associations with anxiety and depression. The implications of these findings are discussed.

Adolescent↗

Risk factors for hepatitis B infection during pregnancy in a Nigerian obstetric population.

We aimed to assess the risk factors for hepatitis B infection among pregnant women in Enugu, southeast Nigeria. This was a prospective case-control study of risk factors for hepatitis B surface antigen positivity among pregnant women seen in two tertiary health institutions in Enugu, southeast Nigeria. It was carried out over an 8-month period, January - August 2005. Of the 1,499 pregnant women attending the antenatal clinic, 4.6% (n = 69) were seropositive for hepatitis B surface antigen. A total of 35 (50.7%) HBsAg positive women and 71 negative controls were interviewed. The risk factors for HBsAg were present in 71% (n = 25) of the positive cases, while only 27% (n = 19) of the negative cases had risk factors. The significant risk factors for HBsAg positivity were higher mean parity, higher number of sexual partners since sexual debut, polygamy and previous positive history of sexually transmitted diseases (STD) (p < 0.05). The two groups did not differ with respect to presence of tattoo or scarification marks, positive history of jaundice or contact with a jaundiced patient, previous blood transfusion or contact with blood products, intravenous drug abuse or sharing personal instruments (p > 0.05). Screening pregnant women for hepatitis B infection on the basis of presence of risk factors may not effective. Universal antenatal screening for HBsAg, health education aimed at reducing risk factors and immunisation of all newborn and those at risk of hepatitis B is advocated.

Adult↗

The marriage squeeze and the rise in informal marriage in Brazil.

Around the world, populations have experienced shortages of one sex or the other at marriageable ages, as a result of mortality declines. The solutions to this problem vary with the cultural context. Declines in the spousal age difference and increases in dowry payments (India) and polygamy (Africa) are two adjustments to a disequilibrium in the marriage market. We hypothesize that in Brazil the marriage market finds its balance by "recycling" men through highly unstable informal unions. Using census and 1984 survey data, we establish the relationship between a marriage squeeze and the increase in informal marriage. Census data and a competing-risks analysis of marriage choice provide evidence that a marriage squeeze has affected both the chances of marrying at all and the type of marriage entered.

Adolescent↗

The evolution of delayed dispersal in cooperative breeders.

Why do the young of cooperative breeders--species in which more than two individuals help raise offspring at a single nest--delay dispersal and live in groups? Answering this deceptively simple question involves examining the costs and benefits of three alternative strategies: (1) dispersal and attempting to breed, (2) dispersal and floating, and (3) delayed dispersal and helping. If, all other things being equal, the fitness of individuals that delay dispersal is greater than the fitness of individuals that disperse and breed on their own, intrinsic benefits are paramount to the current maintenance of delayed dispersal. Intrinsic benefits are directly due to living with others and may include enhanced foraging efficiency and reduced susceptibility to predation. However, if individuals that disperse and attempt to breed in high-quality habitat achieve the highest fitness, extrinsic constraints on the ability of offspring to obtain such high-quality breeding opportunities force offspring to either delay dispersal or float. The relevant constraint to independent reproduction has frequently been termed habitat saturation. This concept, of itself, fails to explain the evolution of delayed dispersal. Instead, we propose the delayed-dispersal threshold model as a guide for organizing and evaluating the ecological factors potentially responsible for this phenomenon. We identify five parameters critical to the probability of delayed dispersal: relative population density, the fitness differential between early dispersal/breeding and delayed dispersal, the observed or hypothetical fitness of floaters, the distribution of territory quality, and spatiotemporal environmental variability. A key conclusion from the model is that no one factor by itself causes delayed dispersal and cooperative breeding. However, a difference in the dispersal patterns between two closely related species or populations (or between individuals in the same population in different years) may be attributable to one or a small set of factors. Much remains to be done to pinpoint the relative importance of different ecological factors in promoting delayed dispersal. This is underscored by our current inability to explain satisfactorily several patterns including the relative significance of floating, geographic biases in the incidence of cooperative breeding, sexual asymmetries in delayed dispersal, the relationship between delayed dispersal leading to helping behavior and cooperative polygamy, and the rarity of the co-occurrence of helpers and floaters within the same population. Advances in this field remain to be made along several fronts.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

The evolution of X-linked genomic imprinting.

We develop a quantitative genetic model to investigate the evolution of X-imprinting. The model compares two forces that select for X-imprinting: genomic conflict caused by polygamy and sex-specific selection. Genomic conflict can only explain small reductions in maternal X gene expression and cannot explain silencing of the maternal X. In contrast, sex-specific selection can cause extreme differences in gene expression, in either direction (lowered maternal or paternal gene expression), even to the point of gene silencing of either the maternal or paternal copy. These conclusions assume that the Y chromosome lacks genetic activity. The presence of an active Y homologue makes imprinting resemble the autosomal pattern, with active paternal alleles (X- and Y-linked) and silenced maternal alleles. This outcome is likely to be restricted as Y-linked alleles are subject to the accumulation of deleterious mutations. Experimental evidence concerning X-imprinting in mouse and human is interpreted in the light of these predictions and is shown to be far more easily explained by sex-specific selection.

Alleles↗

Current status of reproductive behaviour in Africa.

The current annual population growth rate of 3.2% in Africa will double the population by the year 2025. The majority of this population is below 15 years of age, and Africa concurrently also has the highest incidence of infertility in the world. Sexual behaviour, which has been poorly studied in Africa, has a direct impact on reproductive health [including fertility, infertility and sexually transmitted diseases (STDs)]. The multiple cultures and religions which characterize the African continent also affect reproductive health. Factors that have a significant effect on reproductive health in Africa include greater prevalence of extramarital/commercial sexual activity, polygamy, lower prevalence of contraceptives, reliance on traditional practices, high incidence of STDs and teenage pregnancies. High risk reproductive behaviours are predominantly displayed by adolescents, and the prevalence of STDs, including HIV (human immunodeficiency virus), is very high in this group. Pregnancy-related complications are the major cause of health-related problems in 15-19 year old girls. Maternal mortality rates in most countries remain high. Literacy rates affect these behaviours. It is apparent that changing the sexual behaviour of adolescents is one way of reversing the adverse trends, such as STD transmission, unwanted pregnancy and poor general reproductive health.

Adolescent↗

Fine-scale genetic structure and fire-created habitat patchiness in the Australian allodapine bee, Exoneura nigrescens (Hymenoptera: Apidae).

Fire promotes an abundance of nest sites for the stem nesting bee Exoneura nigrescens, which remain viable for approximately 10 years. The finite duration of nesting substrate and localized fire events suggest that migration should minimize genetic structure among suitable habitat patches. Exoneura nigrescens was sampled from 7 localities with a known fire history in southwestern Victoria, Australia. Individual bees were genotyped at 8 microsatellite loci and genic and genotypic analyses applied to examine genetic structure among burn patch localities, within burn patches, and within colonies. Despite relatively short-term availability of nesting substrates, remarkably fine-scale genetic structure was observed both among burn patches and within burn patches. The spatial distribution of relatedness shows a strong pattern of isolation-by-distance at geographic distances to 35 km, suggesting that genetic partitioning among burn patches is, at least in part, a result of dispersal ability. Genetic structure within burn patches includes colonies consisting of close kin with genic partitioning among nests. Relatedness structure within colonies suggests that polygamy, multiple breeding pairs, and a lack of inbreeding typifies the mating system.

Animals↗

Mental health problems among schoolchildren in United Arab Emirates: prevalence and risk factors.

OBJECTIVE: To examine child psychiatric morbidity in an Arab culture. METHOD: Emotional and behavioral problems were investigated in 3,278 schoolchildren aged 6 to 15 years using a two-stage epidemiological study in Al Ain District, United Arab Emirates. Children were screened using standardized questionnaires completed by parents and school physicians in the first stage, and a stratified random sample were interviewed by a child psychiatrist in the second stage. RESULTS: 23.9% of children were reported to have a mental health problem by either the parent or the school health physician. Boys were more often reported to be having problems than girls (1.8:1). Using the Rutter A2 scale for parents, the prevalence estimate for behavioral disorders was 16.5%. The weighted prevalence for DSM-IV disorders was 10.4% for the entire population. The presence of certain culture-specific risk factors such as male gender, number of children in the household, polygamy, and low socioeconomic status were identified for psychiatric disorders. A positive family history and consanguinity were the most significant factors associated with learning disorders. CONCLUSIONS: The prevalence rates of child psychiatric disorders and the symptomatology observed in this Middle East community are similar to those reported in Western studies.

Adolescent↗

Parent-adolescent conflict and its resolution in monogamous and polygamous Bedouin Arab families in southern Israel.

The purpose of this study was twofold: (1) to compare whether children from polygamous family structures significantly differ from children from monogamous family structures with regard to the frequency of parent-child conflict, and (2) whether children from these two structures employ different patterns of family conflict resolution. To address these questions, a random sample of 212 high school students (60.8% monogamous) completed a self-administered survey. The results of MANOVA show no significant differences (p > 0.05) between these two structures with regard to the frequency of parent-child conflict. The results also show similar conflict management styles between these two family structures within each of the following five domains (privacy, school and career, money spending, going out and leisure, and physical appearance). This study is unique in that it is the first empirical research to be conducted in the field of conflict resolution among youth and adolescents in polygamous marital structures and therefore, further investigation is needed to replicate these results utilizing different cross-cultural populations practicing polygamy.

Adolescent↗

The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (family Syngnathidae).

Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto specialized egg-brooding structures that are located on either the male's abdomen or its tail, where they are osmoregulated, aerated, and nourished by specially adapted structures. All syngnathid males exhibit this form of parental care but the brooding structures vary, ranging from the simple ventral gluing areas of some pipefishes to the completely enclosed pouches found in seahorses. We present a molecular phylogeny that indicates that the diversification of pouch types is positively correlated with the major evolutionary radiation of the group, suggesting that this extreme development and diversification of paternal care may have been an important evolutionary innovation of the Syngnathidae. Based on recent studies that show that the complexity of brooding structures reflects the degree of paternal investment in several syngnathid species, we predicted sex-role reversals to be more common among species with more complex brooding structures. In contrast to this prediction, however, both parsimony- and likelihood-based reconstructions of the evolution of sex-role reversal in pipefishes and seahorses suggest multiple shifts in sex roles in the group, independent from the degree of brood pouch development. At the same time, our data demonstrate that sex-role reversal is positively associated with polygamous mating patterns, whereas most nonreversed species mate monogamously, suggesting that selection for polygamy or monogamy in pipefishes and seahorses may strongly influence sex roles in the wild.

Animals↗