Article
Behavioral Sciences
Liqiong Zhou, Erhao Ge, Alberto J. C. Micheletti, Yuan Chen, Juan Du, Ruth Mace
Summary: In a Tibetan population, parents send a son to a monastery to decrease competition between brothers over resources. Men with monk brothers are wealthier than men with non-celibate brothers. This suggests that religious celibacy and new economic opportunities work together to limit the negative effects of brother competition.
BEHAVIORAL ECOLOGY
(2022)
Article
Biology
Isimeme N. Udu, Michael B. Bonsall, Hope Klug
Summary: Parental care has been gained and lost evolutionarily multiple times. The loss of parental care is influenced by low egg and adult death rates, quick egg maturation, and high level of care provided. Evolutionary hysteresis makes it challenging to lose parental care, particularly when eggs develop slowly.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2022)
Article
Economics
Wei Yang, Byron G. Spencer
Summary: This study estimates the impact of the number and genders of siblings on fertility decisions in China. The results show that the number of brothers of the husband has a negative effect on fertility.
JOURNAL OF ECONOMIC BEHAVIOR & ORGANIZATION
(2022)
Article
Family Studies
Ashley Larsen Gibby, Jocelyn S. Wikle, Kevin J. A. Thomas
Summary: Recent studies have found that adoptive parents invest less time and financial resources in adopted children compared to biological children within the same family. However, among families with enrollment differences between siblings, adopted children are significantly less likely than their non-adopted siblings to be enrolled in private school, indicating that adopted children within mixed-adoption families may receive equal or fewer investments than their non-adopted siblings.
JOURNAL OF CHILD AND FAMILY STUDIES
(2021)
Article
Psychology, Developmental
Ran Liu
Summary: This study investigates the relationship between sibship size and gender composition with intrahousehold non-monetary resource distribution using nationally representative survey data from Chinese adolescents. The findings reveal a significant gendered pattern of resource dilution within households, which may not be as evident as inequality in monetary resources.
Article
Public, Environmental & Occupational Health
James Orwa, Samwel Maina Gatimu, Paulino Ariho, Marleen Temmerman, Stanley Luchters
Summary: In Kenya, there are disparities in fertility rates among married women of reproductive age. The study found that education level is the main factor affecting the decline in fertility rates between 2003 and 2014.
Article
Economics
Jie Ma, Xiaojun Yang
Summary: This study examines the role of intra-generational upward mobility in determining the fertility of transition countries. The findings suggest that upward mobility increases fertility through a positive income effect, highlighting the importance of considering upward mobility in boosting fertility and its significant implications for demographic policy.
Article
Economics
Michael Grimm
Summary: High variance in rainfall is associated with significantly higher fertility differentials, indicating a role of rainfall risk in the demographic transition. This effect diminishes as irrigation systems and agricultural machinery become prevalent.
JOURNAL OF ECONOMIC GEOGRAPHY
(2021)
Article
Demography
Emily Smith-Greenaway, Yingyi Lin
Summary: Research based on demographic transition theory has revealed that exposure to mortality has an impact on women's fertility preferences and behaviors. However, previous studies have mainly focused on women, leaving unanswered questions regarding the gendered effects of mortality exposure on fertility-related outcomes for adults. In this research note, we examine data from three African countries with different fertility profiles to explore the associations between sibling mortality exposure and ideal family size among women, men, and couples. The results demonstrate that the associations between adults' sibling mortality exposure and their own and their partners' ideal family sizes differ across countries, highlighting the need to consider gender differences in the study of the mortality-fertility link.
POPULATION STUDIES-A JOURNAL OF DEMOGRAPHY
(2023)
Article
Ecology
Valerio Donini, Luca Pedrotti, Francesco Ferretti, Luca Corlatti
Summary: Investigating the impact of ecological factors on Alpine chamois population dynamics, the study found that birth rate and survival rates were negatively related to climatic variables, density dependence, and interspecific competition with red deer.
ECOLOGY AND EVOLUTION
(2021)
Article
Oncology
Pauline Boucheron, Angelica Anele, Awa U. Offiah, Annelle Zietsman, Moses Galukande, Groesbeck Parham, Leeya F. Pinder, Benjamin O. Anderson, Milena Foerster, Joachim Schuz, Isabel dos-Santos-Silva, Valerie McCormack
Summary: Reproductive characteristics are known risk factors for breast cancer, but their role as prognostic factors is not clear in Sub-Saharan Africa. In a study of 1485 women with breast cancer, each pregnancy was associated with a 5% increase in mortality rates. Recent childbirth was associated with a 52% higher mortality rate in premenopausal women. However, changes in fertility trends had a very small impact on future average survival rate.
INTERNATIONAL JOURNAL OF CANCER
(2023)
Article
Plant Sciences
Rachel J. Standish, Felipe E. Albornoz, Tim K. Morald, Richard J. Hobbs, Mark Tibbett
Summary: This study demonstrates that plant species coexistence in nutrient-impoverished soils is achieved through competition and facilitative interactions among mycorrhizal plants. The different levels of phosphorus supply lead to varying interactions between different plant species and AM fungi, highlighting the importance of below-ground mechanisms in determining community structure.
JOURNAL OF ECOLOGY
(2021)
Article
Demography
Dylan Shane Connor
Summary: This study reveals that parents' choice of names for their children can reflect their fertility behavior, with traditional and Catholic names associated with higher fertility rates among Irish couples circa 1911. However, urbanization in towns and cities was found to lower net fertility rates and weaken preferences for traditional and religious names. This suggests that traditional rural norms played a significant role in driving high fertility rates in Ireland, rather than explicit religious influences.
Article
Ecology
Zhengliang Huang, Yuanzhi Li, Weitao Wang, Buhang Li, Wenqi Luo, Youshi Wang, Chengjin Chu
Summary: This study examined the prevalence of intransitive competition and its relationship with soil fertility in a subtropical forest. The results showed that intransitive competition was common among dominant species and peaked at an intermediate level of soil organic matter. The study also found no positive relationship between intransitivity and demographic trade-offs.
Article
Multidisciplinary Sciences
Cassandra E. Benkwitt, Brett M. Taylor, Mark G. Meekan, Nicholas A. J. Graham
Summary: Cross-ecosystem nutrient subsidies can enhance demographic rates of consumers in recipient ecosystems, influencing population and community dynamics. The study shows that parrotfish around rat-free islands with plentiful seabirds exhibit faster growth rates but lower fecundity compared to those around rat-infested islands with few seabirds, indicating a trade-off between growth and reproduction.
SCIENTIFIC REPORTS
(2021)
Review
Evolutionary Biology
Megan Arnot, Eva Brandl, O. L. K. Campbell, Yuan Chen, Juan Du, Mark Dyble, Emily H. Emmott, Erhao Ge, Luke D. W. Kretschmer, Ruth Mace, Alberto J. C. Micheletti, Sarah Nila, Sarah Peacey, Gul Deniz Salali, Hanzhi Zhang
EVOLUTION MEDICINE AND PUBLIC HEALTH
(2020)
Article
Psychology, Biological
Kiran Basava, Hanzhi Zhang, Ruth Mace
Summary: Beliefs about the fate of humanity and the soul can impact the behaviors of religious groups. The study reveals that beliefs in imminent apocalypse are associated with revolutionary violence, while beliefs in reincarnation tend to be stable in peaceful groups. The findings suggest that conditions generating revolutionary violence may influence beliefs rather than beliefs causing violence.
NATURE HUMAN BEHAVIOUR
(2021)
Article
Multidisciplinary Sciences
Megan Arnot, Emily H. Emmott, Ruth Mace
Summary: Research indicates that life stress increases the frequency of menopause symptoms, but social support may not necessarily buffer against the negative effects of this stress.
Correction
Multidisciplinary Sciences
Hanzhi Zhang, Ting Ji, Mark Pagel, Ruth Mace
SCIENTIFIC REPORTS
(2021)
Article
Anthropology
Bai Peng-Peng, Mattia Mancini, Juan Du, Ruth Mace
Summary: This study examines the impact of land privatization on grassland quality in the eastern Qinghai-Tibetan Plateau, finding that rangeland degradation significantly increases following privatization. Grassland in small individually managed fenced plots deteriorates more than in larger fenced areas with group herding. Moreover, herders' perceptions of their pastures closely match remotely sensed data.
Article
Behavioral Sciences
Alberto J. C. Micheletti, Eva Brandl, Ruth Mace
Summary: The term "cultural evolution" is often used to refer to both a phenomenon and a theory, causing confusion in the field. The behavioral ecology approach does not disregard culture, and different approaches to studying cultural behaviors should coexist. Clarifying key terms is essential for synthesis.
BEHAVIORAL ECOLOGY
(2022)
Article
Biology
Alberto J. C. Micheletti, Erhao Ge, Liqiong Zhou, Yuan Chen, Hanzhi Zhang, Juan Du, Ruth Mace
Summary: Research in a agropastoralist Buddhist population in western China shows that having a monk brother can lead to fathering more children for men and having a monk son can result in more grandchildren for grandparents, suggesting that the religious celibacy practice is adaptive in this community. A model of celibacy is developed to explain the inclusive fitness costs and benefits, revealing that a minority of sons choosing celibacy may be favored if it increases their brothers' reproductive success, but only if the decision is under parental control.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2022)
Article
Behavioral Sciences
Liqiong Zhou, Erhao Ge, Alberto J. C. Micheletti, Yuan Chen, Juan Du, Ruth Mace
Summary: In a Tibetan population, parents send a son to a monastery to decrease competition between brothers over resources. Men with monk brothers are wealthier than men with non-celibate brothers. This suggests that religious celibacy and new economic opportunities work together to limit the negative effects of brother competition.
BEHAVIORAL ECOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Yuan Chen, Erhao Ge, Liqiong Zhou, Juan Du, Ruth Mace
Summary: Inequality between the sexes is a widespread issue both at home and in society. One possible reason for this could be the dispersal of one sex after marriage, which creates gender-specific differences in relatedness to the group. To investigate the impact of sex-biased dispersal on inequality in the sexual division of labor, this study takes advantage of the diverse ecology and social structures in southwest China. By using wearable fitness trackers and validated readings, the researchers found that participants' daily step count was positively correlated with time spent in high-energy activities, such as agriculture and animal husbandry work, and negatively correlated with low-energy activities, such as leisure and relaxation. Comparative analysis revealed that being female and dispersing after marriage were two characteristics that led to an unfavorable division of workload, supporting the hypothesis that males have greater bargaining power when they remain in their natal home.
Editorial Material
Anthropology
Ruth Mace
EVOLUTIONARY HUMAN SCIENCES
(2022)
Editorial Material
Biology
Alberto J. C. Micheletti, Erhao Ge, Liqiong Zhou, Yuan Chen, Juan Du, Ruth Mace
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Biology
Juan Du, Yaming Huang, Peng-Peng Bai, Liqiong Zhou, Sarah Myers, Abigail E. Page, Ruth Mace
Summary: Humans exhibit diverse post-marital residence patterns, with growing recognition that co-residence with kin predicts women's reproductive success, depending on whether they are cooperators or competitors. In a Tibetan population, we found that women living with their own parents have earlier age at first and last birth than those living with parents-in-law. Women co-residing with both sets of parents have the earliest reproductive timing. However, competition with older siblings delays reproduction. Additionally, family planning policies influence reproductive timing, in line with Fisherian expectations. Our study reveals the costs and benefits of co-residing with different kin for women's direct fitness, within cultural constraints on fertility.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Psychology, Educational
Eva Brandl, Emily H. Emmott, Ruth Mace
Summary: Teaching is an important mechanism of social learning, and the way children teach varies across different age groups, which may be influenced by socio-cultural factors.
Article
Anthropology
Eva Brandl, Ruth Mace, Cecilia Heyes
Summary: Teaching is an important process of cultural transmission, and it is argued to be a cognitive instinct shaped by genetic evolution. However, we believe that teaching is a culturally evolved trait that utilizes domain-general cognitive abilities rather than specific cognitive adaptations. Children learn to teach through social interactions, hijacking psychological mechanisms involved in prosociality and cognition. Multiple lines of evidence support this hypothesis.
EVOLUTIONARY HUMAN SCIENCES
(2023)
Article
Anthropology
Qiao-Qiao He, Jun-Wen Rui, Li Zhang, Yi Tao, Jia-Jia Wu, Ruth Mace, Ting Ji
Summary: According to Hamilton's rule, communal breeding by women in matrilineal societies dilutes the investment that men make in their wife's household. A study conducted in the Mosuo community in Southwest China supports this hypothesis, showing that when women breed communally, men are less likely to help on their wife's farm, as the investment would be diluted by other unrelated members.
EVOLUTIONARY HUMAN SCIENCES
(2022)