Search Results (26)

While racial inequalities in assortative mating and fertility have been well documented, the role of neighborhoods has frequently been overlooked in explaining these disparities. In this study, I use restricted birth record data from the state of California with neighborhood-level socioeconomic and demographic data to explore the roles of neighborhoods and structural neighborhood inequality in mediating racial inequality in assortative mating and fertility in 2018 and 2019. Overall, neighborhood disadvantage, particularly disadvantage measured in a neighborhood’s mobility network, mediated a substantial proportion of the disparity in fathers’ educational attainment between White and Black or Hispanic mothers in California in 2018 and 2019. Additionally, while I observe evidence of Black and Hispanic neighborhoods having significantly greater fertility rates than White neighborhoods, this gap can be entirely explained by neighborhood disadvantage. Lastly, a significant share of the fertility gap between less-educated White and Black women is mediated by neighborhood disadvantage. This study motivates more research at the intersection of assortative mating and fertility at the neighborhood scale. Full article

This comprehensive study on the Andalusian Black cattle breed reveals a substantial population decline, with the average herd size decreasing significantly from 305.54 to 88.28 animals per herd. This decline is primarily attributed to agricultural changes and the introduction of foreign meat-focused breeds. The male-to-female ratio shift is noteworthy, with more cows than bulls, impacting selection intensity for both genders. Inbreeding levels, though relatively low historically (5.94%) and currently (7.23%), raise concerns as 37.08% historically and 48.82% currently of the animals exhibit inbreeding. Positive assortative mating is evident, reflected by the increasing non-random mating coefficient (α). Key ancestors play a crucial role in shaping genetic diversity, with one ancestor significantly influencing the current genetic pool and the top 10 ancestors contributing substantially. Breed maintains a conservation index of 2.75, indicating relatively high genetic diversity. Recent conservation efforts have led to an increase in registered animals. The Cañadas Reales, historical transhumance routes, may have contributed to genetic connections among provinces. Challenges include the historical bottleneck, demographic changes, and potential impacts from reproductive practices. The Andalusian Black breed’s conservation necessitates ongoing efforts in genealogical registration, targeted breeding programs, and collaborative initiatives to address the observed demographic shifts and ensure sustainable genetic diversity. Full article

The rhizostomatid scyphozoan Rhopilema nomadica is one of the most notorious marine invasive species established in the eastern Mediterranean Sea. Using seven microsatellite loci, here, we examined the population genetic structures on 587 individual tissue samples collected from 21 sites along the Mediterranean coast of Israel over a period of 16 years. The results indicate unique microsatellite landscapes for all samples, which belong to a single unstructured population. The >20 alleles found in most loci, low fixation index (F) values (average 0.106), and high heterozygosity (average 0.667) suggest random or assortative mating. Additionally, the low overall differentiation (Fst) values (0.043) and pairwise Fst values between the samples collected in different years indicated gene flow and random mating over the years, potentially due to the long-lasting podocytes, scyphistomae, and adults causing a population overlap between the sampled months/years. Likewise, analyses were conducted between seasons, sites, and early/intermediate/late periods of collecting years. These results support the previous analyses performed on the mitochondrial gene cytochrome oxidase subunit I (COI) sequences, altogether indicating a highly polymorphic single unstructured R. nomadica population in the Levant, possibly backed by independent introductions. The results hint to the existence of highly functional connectivity with a genetically highly diverse source population. Full article

The effects of four cycles of recurrent selection on the allele frequencies of simple sequence repeat (SSR) markers and population structure were examined in the Maksimir 3 Synthetic (M3S) maize population (Zea mays L.). Genotyping of 32 plants from each selection cycle at 38 SSR loci revealed that the mean number of alleles per locus and the mean expected heterozygosity were preserved across selection cycles, indicating the maintenance of sufficient genetic variability in the population required for future genetic gain. The Waples test of selective neutrality revealed that genetic drift was the main force in changing allele frequencies in the population. The proportion of selectively non-neutral loci in single cycles of selection varied between 16% and 37%. Some non-neutral loci shared the same genomic locations with previously published QTLs controlling important agronomic traits. An analysis of molecular variance revealed that 5.6% of the genetic variation occurred among and 94.4% within cycle populations. Between 5% and 29% of loci were found to be in a significant Hardy–Weinberg (HW) disequilibrium, with the majority showing an excess of homozygosity. The excess of homozygosity at several loci was highly consistent across cycle populations, suggesting positive assortative mating as a possible cause of the observed HW disequilibrium. Linkage disequilibrium (LD) tests revealed that the M3S population was essentially in linkage equilibrium. The proportion of pairs of loci in significant LD varied from 0.1% to 1.8% across selection cycles, probably due to the effects of genetic drift and epistatic selection. Full article

We studied the reproductive behaviour associated with mate choice by size in three species of White Sea molluscs of the genus Littorina—L. saxatilis, L. obtusata and L. fabalis. Three behavioural patterns were revealed after a comparative analysis of the behaviour of the male snails. The males of L. obtusata, regardless of their size, could mate with all females but preferred to mate with larger ones. The males of L. fabalis chose females of their own size or larger. The males of L. saxatilis mated with females of approximately their own size. In the first case (L. obtusata), there is a free exchange of genes between all the size groups in the population. In the second case (L. fabalis), the gene transfer from small males to females of any size is free but the gene transfer from large males to small females is limited. In the third case (L. saxatilis), the gene flow is limited between groups of individuals of dramatically different size. Thus, in the case of L. saxatilis and L. fabalis, to varying degrees restriction of random mating associated with size assortativity in choosing a mating partner was expressed, which under certain circumstances (divergence of individuals in different econiches, the presence of ecotypes differing in size, lack of stronger natural selection in the other direction) can favour sympatric speciation. The males of all the three periwinkles’ species preferred larger females but sexual selection in favour of larger females was found only in L. obtusata. In the other two species, there were no statistically significant size differences between copulating and non-copulating females. This appears to be due to the occurrence of size-assortative mating in these species, which limits the ability of males to choose larger female partners. Full article

Mate choice is the attempt of an individual to gain higher reproductive fitness by preferring to mate with some individuals and not with others. We studied the role of mate choice in the mating system of the neotropical toad Rhinella arenarum by assessing male reproductive tactics for mate acquisition and the contribution of female choice for pair formation. In a shallow pond in central Argentina, we estimated male mating success and the corresponding reproductive tactics by focal observation. The variation of phenotypic and genotypic traits (size and shape, longevity, vocalization features, heterozygosity) was related to the observed mating success in 110 males. The phonotactic response of 21 reproductive females to conspecific advertisement call features was tested in arena experiments. Mating success was limited to 32 males, pair formation was size-assortative. The dominant reproductive tactics were advertising from call positions near suitable breeding sites and pre-mating fights with intruding males, whereas the interception of amplectant pairs and the displacement of mated males were never observed. Female phonotaxis was directed to conspecific choruses but complex and simple call structures were not distinguished. We conclude that the mating system is a lek combining pre-mating fights among males and female choice of slightly smaller males. Fights interfere with female choice, undermining size-assortative mating. This is a unique system in the R. marina species group, in which interception behavior dominates reproduction. Full article

It has been suggested that parental mathematics anxiety may influence their children’s mathematics anxiety, attitudes, and performance. It remains an open question whether these parent-child associations differ by parental sex or parental involvement. We tested 249 Dutch-speaking Belgian participants, forming 83 (biological) mother–father–child trios. The 83 children (age: M = 5.74; SD = 0.30) attended Kindergarten. We tested their nonsymbolic comparison, symbolic numerical magnitude processing, numeral recognition, arithmetic, and matrix reasoning. We assessed both parents’ arithmetic skills, math anxiety, educational level, and division of care. More math-anxious parents tended to be less highly educated (r~0.42) and poorer at math (r~0.30). Compared to fathers, mothers had lower arithmetic, higher math anxiety, and higher educational level. Assortative mating (i.e., a significant spousal correlation) was found for educational level and arithmetic. Mothers’ (but not fathers’) educational level predicted children’s arithmetic scores (r = 0.31). Other parent-offspring correlations were non-significant. Most of the children’s test scores are intercorrelated. The parental characteristic that best predicted five- and six-year-olds’ arithmetic performance was maternal educational level rather than mathematical anxiety or performance. We discuss these findings in relation to the used measures, parental gender and involvement, children’s age, statistical power, and genetic and environmental transmission. The field is just starting to understand whether and how mathematics anxiety and the skills of parents influence those of their offspring. Full article

Females and males of the abundant heteropteran species Pyrrhocoris apterus (L.) mate with the larger of the available partners. The male benefits from copulation with a large female, which is more productive than a small female. However, the benefit to females from copulation with a large male has not yet been investigated. Overwintered sexually immature adults were transferred from the field to indoors for a long day at 25 °C and subsequently kept as female-male pairs with different partner size ratios. The female lays eggs in several successive clutches. We investigated the influence of male size on the number and weight of eggs in individual clutches and the time elapsed from the transfer to their deposition. These characteristics of reproduction were first regressed on female size, and residuals of this regression were then regressed on male size. The positive effect of increasing male size on the characteristics of female reproduction manifested as a significant value of the latter regressions. The expected positive effect of increasing male body size on female reproductive characteristics was not detected. Several reasons for this deficiency are discussed. Full article

An increase in the prevalence of autosomal recessive deafness 1A (DFNB1A) in populations of European descent was shown to be promoted by assortative marriages among deaf people. Assortative marriages became possible with the widespread introduction of sign language, resulting in increased genetic fitness of deaf individuals and, thereby, relaxing selection against deafness. However, the effect of this phenomenon was not previously studied in populations with different genetic structures. We developed an agent-based computer model for the analysis of the spread of DFNB1A. Using this model, we tested the impact of different intensities of selection pressure against deafness in an isolated human population over 400 years. Modeling of the “purifying” selection pressure on deafness (“No deaf mating” scenario) resulted in a decrease in the proportion of deaf individuals and the pathogenic allele frequency. Modeling of the “relaxed” selection (“Assortative mating” scenario) resulted in an increase in the proportion of deaf individuals in the first four generations, which then quickly plateaued with a subsequent decline and a decrease in the pathogenic allele frequency. The results of neutral selection pressure modeling (“Random mating” scenario) showed no significant changes in the proportion of deaf individuals or the pathogenic allele frequency after 400 years. Full article

The black soldier fly (BSF), Hermetia illucens, is a promising candidate for the emerging insect farming industry with favourable characteristics for both bioremediation and production of animal delivered nutritive and industrial compounds. The genetic management of commercial colonies will become increasingly important for the sustainability of the industry. However, r-selected life history traits of insects pose challenges to conventional animal husbandry and breeding approaches. In this study, the long-term genetic effects of mass-rearing were evaluated as well as mating systems in the species to establish factors that might influence genetic diversity, and by implication fitness and productivity in commercial colonies. Population genetic parameters, based on microsatellite markers, were estimated and compared amongst two temporal wild sampling populations and four generations (F28, F48, F52, and F62) of a mass-reared colony. Furthermore, genetic relationships amongst mate pairs were evaluated and parentage analysis was performed to determine the oc-currence of preferential mate choice and multiple paternity. The mass-reared colony showed a reduction in genetic diversity and evidence for inbreeding with significant successive generational genetic differentiation from the wild progenitor population. Population-level analysis also gave the first tentative evidence of positive assortative mating and genetic polyandry in BSF. The homoge-neity of the mass-reared colony seems to result from a dual action caused by small effective popu-lation size and increased homozygosity due to positive assortative mating. However, the high ge-netic diversity in the wild and a polyandrous mating system might suggest the possible restoration of diversity in mass-reared colonies through augmentation with the wild population. Full article

Traditional evolution algorithms tend to start the search from scratch. However, real-world problems seldom exist in isolation and humans effectively manage and execute multiple tasks at the same time. Inspired by this concept, the paradigm of multi-task evolutionary computation (MTEC) has recently emerged as an effective means of facilitating implicit or explicit knowledge transfer across optimization tasks, thereby potentially accelerating convergence and improving the quality of solutions for multi-task optimization problems. An increasing number of works have thus been proposed since 2016. The authors collect the abundant specialized literature related to this novel optimization paradigm that was published in the past five years. The quantity of papers, the nationality of authors, and the important professional publications are analyzed by a statistical method. As a survey on state-of-the-art of research on this topic, this review article covers basic concepts, theoretical foundation, basic implementation approaches of MTEC, related extension issues of MTEC, and typical application fields in science and engineering. In particular, several approaches of chromosome encoding and decoding, intro-population reproduction, inter-population reproduction, and evaluation and selection are reviewed when developing an effective MTEC algorithm. A number of open challenges to date, along with promising directions that can be undertaken to help move it forward in the future, are also discussed according to the current state. The principal purpose is to provide a comprehensive review and examination of MTEC for researchers in this community, as well as promote more practitioners working in the related fields to be involved in this fascinating territory. Full article

The family Ciconiidae comprises 19 extant species which are highly social when nesting and foraging. All species share similar morphotypes, with long necks, a bill, and legs, and are mostly coloured in the achromatic spectrum (white, black, black, and white, or shades of grey). Storks may have, however, brightly coloured integumentary areas in, for instance, the bill, legs, or the eyes. These chromatic patches are small in surface compared with the whole body. We have analyzed the conservatism degree of colouration in 10 body areas along an all-species stork phylogeny derived from BirdTRee using Geiger models. We obtained low conservatism in frontal areas (head and neck), contrasting with a high conservatism in the rest of the body. The frontal areas tend to concentrate the chromatic spectrum whereas the rear areas, much larger in surface, are basically achromatic. These results lead us to suggest that the divergent evolution of the colouration of frontal areas is related to species recognition through visual cue assessment in the short-range, when storks form mixed-species flocks in foraging or resting areas. Full article

Host plant preference during the larval stage may help shape not only phenotypic plasticity but also behavioral isolation. We assessed the effects of diet on population parameters and mate choice in Spodoptera litura. We raised larvae fed on tobacco, Chinese cabbage, or an artificial diet, and we observed the shortest developmental time and highest fecundity in individuals fed the artificial diet. However, survival rates were higher for larvae on either of the natural diets. Population parameters including intrinsic rate of increase and finite rate of increase were significantly higher with the artificial diet, but this diet led to a lower mean generation time. Copulation duration, copulation time, and number of eggs reared significantly differed between diets. In terms of mate choice, females on the artificial diet rarely mated with males fed on a natural host. Our results support the hypothesis that different diets may promote behavioral isolation, affecting mating outcomes. Thus, findings for populations fed an artificial diet may not reflect findings for populations in the field. Full article

Previous studies have shown that marriage is related with people’s health. Based on data from the Volume A of China Migrants Dynamic Survey (CMDS_A) in 2017 (N = 127,829), this study attempted to document the degree of educational assortative mating in Chinese internal migrants, as well as how it evolves over time, and further analyze the relationship between educational assortative mating and people’s self-rated health (SRH). The results indicated that the proportion of educational homogamy kept increasing and gradient marriage kept decreasing over time both in male and female. “Educational homogamy” (58.8%) and “male more educated” (27.2%) were still the main marital education matching patterns in first-married couples of Chinese internal migrants. Educational homogamy was beneficial to promote people’s SRH and educational hypogamy would impair their SRH, and the negative effects of educational hypogamy on SRH was stronger in female than in male. The gender equality of educational opportunities increases the degree of educational assortative mating in Chinese internal migrants. Educational attainment is playing a more and more important role in “love” marriages. “Likes attract likes” is not just about love, but also an important part of health. Full article

Several phenological phases mark the seasonal growth pattern in temperate woody perennials. To gain further insight into the way these phases react on an altering growth environment, we tested whether vegetative and reproductive phenophases in a shrub species respond differentially among different genetic entities and between two different planting sites. We scored leaf bud burst, flower opening, leaf senescence and leaf fall on 267 ramets of Prunus padus L. belonging to 53 genotypes that were sampled in 9 local populations, and that were planted in 2 common gardens in the northern part of Belgium. The data were processed with cumulative logistic regression. The contribution of genetic and non-genetic components to the total variability varied between the four studied seasonal phenophases. The timing of flower opening displayed the smallest relative amount of intragenotypic variance (between ramets), suggesting a stronger genetic control and a lesser need at the individual plant level for plastic fine tuning to the micro-environment. In addition, whereas leaf bud burst showed the highest relative variance at the interpopulation level among all phenophases, probably at least partly attributable to local adaptation, flower opening displayed the highest intergenotypic variance, which may have been promoted more by assortative mating. Spring phenophases were strongly correlated (r = 0.89) as well as the autumnal phenophases (r = 0.72). Flower opening was not correlated with the autumnal phenophases. Timing of leaf bud burst and leaf senescence were negatively correlated, demonstrating that the length of the growing season enlarged or diminished among the studied genotypes. Although the two planting sites were only 24 km apart, all phenophases were advanced at the less exposed site, indicating a phenotypic plastic response. Together, our results suggest that in P. padus, flowering is less sensitive to environmental variation than leaf bud break and may show a lesser impact of a changing environment on this reproductive phenophase. Full article