The Trivers-Willard hypothesis (TWH) states that parents in good condition preferentially produce the sex with a higher variation in reproductive success, whereas parents in bad condition favour the opposite sex. Theorists distinguish two variants of the TWH: (a) a biased sex-ratio at birth and (b) biased parental investment after birth. It has been argued before that the conditions stated by Trivers and Willard (good condition is inherited and affects reproductive success more strongly for one of the sexes) are sufficient for the sex-ratio version but insufficient for the investment version of the TWH. However, it has not yet been investigated how these conditions affect parental investment in high and low quality parents, depending on the life-cycle of a species. The present study aims to fill this gap by introducing a multi-stage matrix population model with nonlinear mating to describe the effects of parental investment after birth on the reproductive values of male and female individuals. Using methods from adaptive dynamics and evolutionary invasion analysis, evolutionary trajectories and evolutionarily stable strategies are derived for different parameterizations of the model. Simulation results demonstrate that the conditions given by Trivers and Willard produce a general bias of parental investment towards the sex with higher variance in reproductive value. This bias is stronger for low-quality parents than for high-quality parents and matches the expected marginal offspring reproductive values for parental investment.
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http://dx.doi.org/10.1016/j.tpb.2019.10.001 | DOI Listing |
J Ethn Migr Stud
August 2024
Institute of Sociology and Cultural Organisation (ISCO), Leuphana University of Lüneburg, Lüneburg, Germany.
State authorities in Europe invest immense resources in what the EU insists on calling the 'fight against illegal migration'. Based on ethnographic research in two German cities, this paper shows that a tough approach towards illegalised migration can only be implemented through state practices that operate at the margins of, or even cross, the boundaries of what is legally permissible. This argument is developed through an analysis of informal practices that frontline staff in registry offices and migration administrations deploy to prevent, or at least disturb, illegalised migrants' attempts to regularise their status by becoming the parent of child that is entitled to German citizenship.
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Learning Research Development Center, University of Pittsburgh, Pittsburgh, PA, USA.
Inequalities in the distribution of wealth among families with children may have deleterious health consequences, especially for adolescent children. Marked by significant psychosocial and physiological changes, adolescence is a period when socioeconomic differences in chronic disease risk factors are observed. Unfortunately, research on socioeconomic inequalities in adolescent health has overlooked wealth, focusing instead on differences in health based on household income and parental educational attainment.
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December 2024
Gulbali Institute for Agriculture, Water and Environment, Charles Sturt University, Wagga Wagga, NSW 2678, Australia.
Wheat () is grown on more arable acreage than any other food crop and has been well documented to produce allelochemicals. Wheat allelochemicals include numerous benzoxazinoids and their microbially transformed metabolites that actively suppress growth of weed seedlings. Production and subsequent release of these metabolites by commercial wheat cultivars, however, has not yet been targeted by focussed breeding programmes seeking to develop more competitive crops.
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December 2024
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
The social complexity hypothesis suggests that complex social interactions drive the evolution of sophisticated communicative signals. While the relationship between social communication and the complexity of sound and color signals has been extensively studied, the correlation between social communication and movement-based visual signal complexity remains underexplored. In this study, we selected the Asian agamid lizard, , as our model system.
View Article and Find Full Text PDFPLoS One
January 2025
School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, United States of America.
Identifying processes that promote coral reef recovery and resilience is crucial as ocean warming becomes more frequent and severe. Sexual reproduction is essential for the replenishment of coral populations and maintenance of genetic diversity; however, the ability for corals to reproduce may be impaired by marine heatwaves that cause coral bleaching. In 2014 and 2015, the Hawaiian Islands experienced coral bleaching with differential bleaching susceptibility in the species Montipora capitata, a dominant reef-building coral in the region.
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