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1.
BMC Genomics ; 25(1): 171, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38350872

RESUMO

BACKGROUND: The highly eusocial stingless bees are crucial pollinators of native and agricultural ecosystems. Nevertheless, genomic studies within this bee tribe remain scarce. We present the genome assembly of the stingless bee Melipona bicolor. This bee is a remarkable exception to the typical single-queen colony structure, since in this species, multiple queens may coexist and share reproductive duties, resulting in genetically diverse colonies with weak kinship connections. As the only known genuinely polygynous bee, M. bicolor's genome provides a valuable resource for investigating sociality beyond kin selection. RESULTS: The genome was assembled employing a hybrid approach combining short and long reads, resulting in 241 contigs spanning 259 Mb (N50 of 6.2 Mb and 97.5% complete BUSCOs). Comparative analyses shed light on some evolutionary aspects of stingless bee genomics, including multiple chromosomal rearrangements in Melipona. Additionally, we explored the evolution of venom genes in M. bicolor and other stingless bees, revealing that, apart from two genes, the conserved repertoire of venom components remains under purifying selection in this clade. CONCLUSION: This study advances our understanding of stingless bee genomics, contributing to the conservation efforts of these vital pollinators and offering insights into the evolutionary mechanisms driving their unique adaptations.


Assuntos
Ecossistema , Comportamento Social , Abelhas/genética , Animais , Reprodução , Cromossomos/genética
2.
Am Nat ; 203(1): 139-146, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38207139

RESUMO

AbstractThe coexistence of multiple reproductives in eusocial insects is widespread, yet the decisions leading to additional queen acceptance are not well understood. Unlike in vertebrates, acceptance decisions are likely controlled by the more numerous helper population rather than the parent reproductive. Yet there are likely to be queen-worker differences in acceptance criteria because workers and queens differ in their relatedness to a secondary queen. We develop a model that examines queen-worker conflict in two scenarios: accepting a queen's sister or daughter. We additionally ask how the mating frequency and split sex ratios affect the outcomes of these conflicts. Our results reveal that conflict over queen acceptance is highest in monandrous mating systems. We identify a "window of conflict" in which a queen is selected to accept her sister but her workers do not. Our result, that polyandry neutralizes conflict over acceptance thresholds, suggests that conflict suppression may be an additional contributor to the maintenance of polyandrous mating systems.


Assuntos
Insetos , Reprodução , Animais , Feminino , Humanos , Razão de Masculinidade
3.
Zoolog Sci ; 41(2): 201-209, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38587915

RESUMO

Dispersal increases the costs of feeding and predation risk in the new environment and is reported to be biased toward habitats similar to the natal region in some mammals. The benefits and costs of dispersal often differ between sexes, and most mammals show male-biased dispersal in relation to a polygamous mating system. Japanese serow is generally a solitary and monogamous species. However, recent studies have shown that the sociality of serows on Mt. Asama differs between habitat types. In the mountain forests with low forage availability, solitary habits and social monogamy were observed, while, in alpine grasslands, female grouping and social polygyny were observed, which is probably due to abundant forage availability. We investigated the effects of habitat characteristics and sociality on the dispersal of serows using fecal and tissue samples from two different habitats on Mt. Asama. The Fst value between the two areas was significantly positive, and the mean relatedness within areas was significantly higher than that between areas, which suggests limited gene flow and natal habitat-biased dispersal. Bayesian clustering analysis showed unidirectional gene flow from forest to grassland, which was probably due to the high forage availability of the grassland. Analyses of the assignment index and mean relatedness did not show male-biased dispersal, even in the grassland, where serows were polygynous. Thus, polygyny in the grassland is not linked to male-biased dispersal. In summary, our study suggests that dispersal patterns in Japanese serows are affected by habitat rather than social differences.


Assuntos
Ecossistema , Mamíferos , Feminino , Masculino , Animais , Teorema de Bayes , Japão
4.
Arch Sex Behav ; 53(2): 611-627, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38030825

RESUMO

Polygamy is a form of "one-sided" consensually non-monogamous relationship where one person has multiple committed partners, each of whom is only involved with that one person. It was likely a reoccurring feature of ancestral mating that posed adaptive problems for our ancestors. Yet polygamy, and multi-partnering more generally, is understudied in Western cultures, raising questions about the existence of polygamous interest and whether this is calibrated adaptively to personal conditions. In two studies, we examined polygamous interest in two heterosexual online samples from the UK. In Study 1 (N = 393), modest interest was found for polygamous relationships overall. Men were six times more open to polygyny than women, but there was little sex difference in openness to polyandry. Further analysis revealed that all forms of multi-partnering were undesirable relative to singlehood and monogamy; however, consensual multi-partner relationships were less undesirable than non-consensual ones. Sex differences were largest for polygyny and arrangements where men had agreed access to a casual partner alongside a committed one, yet these were two of the most acceptable forms of multi-partnering when men and women's responses were combined. Sociosexuality positively predicted interest in most forms of multi-partnering. Study 2 (N = 735) focused on polygyny and added status-linked traits as predictors. The results of Study 1 were broadly replicated, though the status-linked traits did not predict polygynous interest specifically. Instead, sociosexuality and male intrasexual competitiveness uniquely predicted general interest in multi-partner relationships. Overall, interest in polygamy appears to emerge despite social discouragement and sex differences in interest track the relative costs and benefits associated with it. However, there is no strong evidence that polygamous interest is uniquely calibrated to personal conditions when compared to other forms of multi-partnering.


Assuntos
Heterossexualidade , Casamento , Feminino , Humanos , Masculino , Estado Civil , Caracteres Sexuais , Reino Unido
5.
BMC Public Health ; 24(1): 2735, 2024 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-39379911

RESUMO

BACKGROUND: Intimate partner violence is more common in polygynous couples than monogamous couples, but the extent that this association is modified by the husband's alcohol consumption is unknown. The objectives of this study are: (1) To describe the extent to which polygyny is associated with self-reported experience of intimate partner violence among women receiving postpartum care; (2) To describe the extent to which the mentioned association is modified by the husband's alcohol consumption. METHODS: We conducted a hospital-based cross-sectional study among women age 18 years or older receiving postpartum care at 8 public hospitals in 3 provinces in Northern and Northeastern Thailand using self-administered questionnaires. We analyzed data using descriptive statistics, logistic regression, and stratified analyses. RESULTS: A total of 1207 women agreed to participate in the study, 8% of whom reported that their husbands practiced polygyny. Women in a polygynous relationship were more likely than women in monogamous relationships to experience intimate partner violence (11.7% vs. 3.6%, Adjusted OR = 2.23; 95% CI = 0.94, 5.26). The prevalence of intimate partner violence was relatively low in both groups among women whose husbands did not drink (2.9% vs. 0%, Adjusted OR = N/A), and very high in both groups among those whose husbands binge-drank (46.2% vs. 20.8%, Adjusted OR = 9.54; 95% CI = 1.10, 82.54). However, the Breslow-Day Test of Homogeneity suggested that there was no statistically significant effect modification (p-value = 0.259). CONCLUSION: Stakeholders in intimate partner violence should consider both alcohol use (particularly binge-drinking) and polygyny as risk factors for intimate partner violence. However, caveats regarding study design, misclassification and potential information bias, and lack of generalizability should be considered in the interpretation of the study findings.


Assuntos
Consumo de Bebidas Alcoólicas , Violência por Parceiro Íntimo , Período Pós-Parto , Cônjuges , Humanos , Feminino , Tailândia/epidemiologia , Estudos Transversais , Adulto , Consumo de Bebidas Alcoólicas/epidemiologia , Consumo de Bebidas Alcoólicas/psicologia , Violência por Parceiro Íntimo/estatística & dados numéricos , Violência por Parceiro Íntimo/psicologia , Adulto Jovem , Cônjuges/estatística & dados numéricos , Cônjuges/psicologia , Casamento/estatística & dados numéricos , Adolescente , Masculino , Inquéritos e Questionários , Prevalência
6.
J Biosoc Sci ; 56(4): 784-795, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38173346

RESUMO

While the practice of polygyny is common in Ghana, little is known about its impact on the use of reproductive health services. The aim of this study was to assess the relationship between polygynous marriage and the utilisation of skilled antenatal care (ANC), assisted skilled birth, and modern contraceptive services among married women in Ghana. Secondary data from the 2017 Ghana Maternal Health Survey were used for this study. The study included a weighted sample of 9,098 married women aged 15-49 years. We used multivariable logistic regression models to assess the association between polygyny and each outcome variables. Sensitivity analysis was conducted to assess the dose-response relationship between polygyny and each outcome variable. The prevalence of eight or more ANC contacts, assisted skilled births, and use of modern contraception were 47.0%, 81.4%, and 25.4%, respectively. The prevalence of women in polygynous marriages was 15.3%. Compared to monogynous marriage, polygynous marriage was associated with 19% lower odds of having eight plus ANC contacts (adjusted odds ratio [aOR] 0.81, 95% CI: 0.69, 0.96), 25% lower odds of having assisted skilled birth (aOR 0.75, 95% CI: 0.63, 0.89), and 19% lower odds of modern contraceptive utilisation (aOR 0.81, 95% CI: 0.66, 0.99). Interventions on reproductive health may need to prioritise women in polygynous marriages in order to improve the utilisation of skilled ANC, assisted skilled birth, and modern contraceptive services.


Assuntos
Casamento , Serviços de Saúde Reprodutiva , Humanos , Feminino , Gana/epidemiologia , Adulto , Casamento/estatística & dados numéricos , Adolescente , Pessoa de Meia-Idade , Adulto Jovem , Serviços de Saúde Reprodutiva/estatística & dados numéricos , Gravidez , Comportamento Contraceptivo/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Anticoncepção/estatística & dados numéricos , Cuidado Pré-Natal/estatística & dados numéricos , Estudos Transversais , Modelos Logísticos
7.
Mol Ecol ; 32(5): 1087-1097, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36541826

RESUMO

Indirect genetic effects describe phenotypic variation that results from differences in the genotypic composition of social partners. Such effects represent heritable sources of environmental variation in eusocial organisms because individuals are typically reared by their siblings. In the fire ant Solenopsis invicta, a social supergene exhibits striking indirect genetic effects on worker regulation of colony queen number, such that the genotypic composition of workers at the supergene determines whether colonies contain a single or multiple queens. We assessed the direct and indirect genetic effects of this supergene on gene expression in brains and abdominal tissues from laboratory-reared workers and compared these with previously published data from field-collected prereproductive queens. We found that direct genetic effects caused larger gene expression changes and were more consistent across tissue types and castes than indirect genetic effects. Indirect genetic effects influenced the expression of many loci but were generally restricted to the abdominal tissues. Further, indirect genetic effects were only detected when the genotypic composition of social partners differed throughout the development and adult life of focal workers, and were often only significant with relatively lenient statistical cutoffs. Our study provides insight into direct and indirect genetic effects of a social supergene on gene regulatory dynamics across tissues and castes in a complex society.


Assuntos
Formigas , Comportamento Social , Humanos , Animais , Genótipo , Regulação da Expressão Gênica , Formigas/genética
8.
J Theor Biol ; 557: 111330, 2023 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-36279958

RESUMO

The moral rule "Risk your life to save your family members" is, at the same time, a biological phenomenon. The prominent population geneticist, J.B.S. Haldane told his friends that he would risk his life to save two drowning brothers, but not one - so the story goes. In biological terms, Haldane's arithmetic claims that sib altruism is evolutionarily rational, whenever by "self-sacrifice" an altruistic gene "rescues", on average, more than one copy of itself in its lineage. Here, we derive conditions for evolutionary stability of sib altruism, using population genetic models for three mating systems (monogamy, promiscuity and polygyny) with linear and non-linear group effect on the siblings' survival rate. We show that for all considered selection situations, the condition of evolutionary stability is equivalent to Haldane's arithmetic. The condition for evolutionary stability is formulated in terms of genetic relatedness and the group effect on the survival probability, similarly to the classical Hamilton's rule. We can set up a "scale of mating systems", since in pairwise interactions the chance of evolutionary stability of sib altruism decreases in this order: monogamy, polygyny and promiscuity. Practice of marrying and siblings' solidarity are moral rules in a secular world and in various religious traditions. These moral rules are not evolutionarily independent, in the sense that the subsistence of sib altruism is more likely in a monogamous population.


Assuntos
Altruísmo , Seleção Genética , Humanos , Masculino , Evolução Biológica , Reprodução , Modelos Genéticos
9.
J Anim Ecol ; 92(4): 838-849, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36708046

RESUMO

An understanding of the drivers of individual fitness is a fundamental component of evolutionary ecology and life-history theory. Reproductive senescence, mate and mating tactic choice and latent heterogeneity in individual quality interact to affect individual fitness. We sought to disentangle the effects of these fitness drivers, where longitudinal data are required to understand their respective impacts. We used reproductive allocation and success data from a long-term (1989-2018) study of white-throated dippers Cinclus cinclus in Switzerland to simultaneously examine the effects of female and male age, mating tactic, nest initiation date and individual heterogeneity on reproductive performance. We modelled quadratic and categorical effects of age on reproductive parameters. The probability of polygyny increased with age in both sexes before declining in older age classes. Similarly, hatching probability in monogamous pairs and the number of nestlings hatched in both monogamous and polygynous pairs increased with female age before declining later in life. As predicted, offspring survival in monogamous pairs increased with male age before declining in older age classes, but male age had no effect on offspring survival in polygynous nesting attempts. Our results demonstrate that parental age, mating tactic and individual heterogeneity all affect reproductive success, and that the impacts of senescent decline are expressed across different demographic components as a function of sex-specific senescent decline and mating tactic.


Assuntos
Passeriformes , Reprodução , Masculino , Feminino , Animais , Comportamento Sexual Animal , Envelhecimento , Ecologia
10.
Biol Lett ; 19(11): 20230391, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37991194

RESUMO

In many animals, males compete for access to fertile females. The resulting sexual selection leads to sex differences in morphology and behaviour, but may also have consequences for physiology. Pectoral sandpipers are an arctic-breeding polygynous shorebird in which males perform elaborate displays around-the-clock and move over long distances to sample potential breeding sites, implying the need for physiological adaptations to cope with extreme endurance. We examined the oxygen carrying capacity of pectoral sandpipers, measured as the volume percentage of red blood cells in blood (haematocrit, Hct). We found a remarkable sex difference in Hct levels, with males having much higher values (58.9 ± 3.8 s.d.) than females (49.8 ± 5.3 s.d.). While Hct values of male pectoral sandpipers are notable for being among the highest recorded in birds, the sex difference we report is unprecedented and more than double that of any previously described. We also show that Hct values declined after arrival to the breeding grounds in females, but not in males, suggesting that males maintain an aerobic capacity during the mating period equivalent to that sustained during trans-hemispheric migration. We conclude that sexual selection for extreme physical performance in male pectoral sandpipers has led to exceptional sex differences in oxygen carrying capacity.


Assuntos
Charadriiformes , Caracteres Sexuais , Animais , Feminino , Masculino , Seleção Sexual , Conservação dos Recursos Naturais , Comportamento Sexual Animal/fisiologia , Aves/fisiologia , Charadriiformes/fisiologia
11.
J Evol Biol ; 35(8): 1031-1044, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35759556

RESUMO

Most supergenes discovered so far are young, occurring in one species or a few closely related species. An ancient supergene in the ant genus Formica presents an unusual opportunity to compare supergene-associated phenotypes and the factors that influence the persistence of polymorphism in different species. We investigate the genetic architecture of social organization in Formica francoeuri, an ant species native to low- and mid-elevation semiarid regions of southern California, and describe an efficient technique for estimating mode of social organization using population genomic data. Using this technique, we show that F. francoeuri exhibits polymorphism in colony social organization and that the phenotypic polymorphism is strongly associated with genotypes within the Formica social supergene region. The distribution of supergene haplotypes in F. francoeuri differs from that of related species Formica selysi in that colonies with multiple queens contain almost exclusively workers that are heterozygous for alternative supergene haplotypes. Moreover, heterozygous workers exhibit allele-specific expression of the polygyne-associated haplotype at the candidate gene Knockout, which is thought to influence social organization. We also report geographic population structure and variation in worker size across a large fraction of the species range. Our results suggest that, although the Formica supergene is conserved within the genus, the mechanisms that maintain the supergene and its associated polymorphisms differ among species.


Assuntos
Formigas , Alelos , Animais , Formigas/genética , Genótipo , Haplótipos , Polimorfismo Genético , Comportamento Social
12.
Mol Ecol ; 30(11): 2511-2527, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33811410

RESUMO

Invasive species are a global threat to biodiversity, and understanding their history and biology is a major goal of invasion biology. Population-genetic approaches allow insights into these features, as population structure is shaped by factors such as invasion history (number, origin and age of introductions) and life-history traits (e.g., mating system, dispersal capability). We compared the relative importance of these factors by investigating two closely related ants, Tetramorium immigrans and Tetramorium tsushimae, that differ in their social structure and invasion history in North America. We used mitochondrial DNA sequences and microsatellite alleles to estimate the source and number of introduction events of the two species, and compared genetic structure among native and introduced populations. Genetic diversity of both species was strongly reduced in introduced populations, which also differed genetically from native populations. Genetic differentiation between ranges and the reduction in microsatellite diversity were more severe in the more recently introduced and supercolonial T. tsushimae. However, the loss of mitochondrial haplotype diversity was more pronounced in T. immigrans, which has single-queen colonies and was introduced earlier. Tetramorium immigrans was introduced at least twice from Western Europe to North America and once independently to South America. Its monogyny might have limited genetic diversity per introduction, but new mutations and successive introductions over a long time may have added to the gene pool in the introduced range. Polygyny in T. tsushimae probably facilitated the simultaneous introduction of several queens from a Japanese population to St. Louis, USA. In addition to identifying introduction pathways, our results reveal how social structure can influence the population-genetic consequences of founder events.


Assuntos
Variação Genética , Genética Populacional , Europa (Continente) , Espécies Introduzidas , Repetições de Microssatélites , América do Norte , América do Sul
13.
Horm Behav ; 136: 105062, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34601430

RESUMO

Pair bonding is a psychological construct that we attempt to operationalize via behavioral and physiological measurements. Yet, pair bonding has been both defined differently in various taxonomic groups as well as used loosely to describe not just a psychological and affective phenomenon, but also a social structure or mating system (either social monogamy or just pair living). In this review, we ask the questions: What has been the historical definition of a pair bond? Has this definition differed across taxonomic groups? What behavioral evidence do we see of pair bonding in these groups? Does this observed evidence alter the definition of pair bonding? Does the observed neurobiology underlying these behaviors affect this definition as well? And finally, what are the upcoming directions in which the study of pair bonding needs to head?


Assuntos
Apego ao Objeto , Ligação do Par , Animais , Proteínas de Ligação a DNA
14.
BMC Public Health ; 21(1): 1677, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34525988

RESUMO

BACKGROUND: Polygyny occurs when a man has more than one wife at the same time. It often contributes to poor health among family members, particularly young children. It encourages the spread of sexually transmitted infections (STIs) including HIV/AIDS. The determinants of polygyny have not yet been adequately explored in Ethiopia. This study adds to the body of knowledge concerning the prevalence and distribution of polygyny in the country. METHODS: This study is a secondary analysis of the 2016 Ethiopian Demographic and Health Survey (EDHS) data. Using a two-stage stratified cluster sampling, 7470 married men were selected. After verifying the assumptions of multilevel logistic regression analysis, Stata version 14.0 was used to analyse the data. A multilevel mixed-effects logistic regression model was used to identify predictors of polygyny. An adjusted odds ratio with a 95% confidence interval was used to measure the association. A p-value of < 0.05 was considered to indicate statistical significance. RESULTS: Age from 30 to 44 years [AOR = 5.78, 95% CI = (3.13, 10.7)], age from 45 to 59 years [AOR = 16.5, 95% CI = (8.59, 31.8)], men with primary education or no formal education [AOR = 3.40, 95% CI = (1.50, 7.69)], being Muslim [AOR = 2.47, 95% CI = (1.28, 4.77)], sexual initiation at or above the age of 18 years [AOR = 0.46, 95% CI = (0.30, 0.68)] and being from a less developed region of Ethiopia [AOR = 3.67, 95% CI = (2.30, 5.83)] were factors associated with polygyny. CONCLUSION: Both individual and community level factors were identified as predictors of polygyny. Improving educational attainment and delaying men's sexual debut could encourage the reduction of polygyny in Ethiopia.


Assuntos
Casamento , Homens , Adolescente , Adulto , Pré-Escolar , Etiópia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multinível , Razão de Chances
15.
Ann Hum Biol ; 48(1): 30-36, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33470846

RESUMO

BACKGROUND: Consanguinity has been extensively studied in the context of its negative health outcomes for offspring and socio-demographic factors, but little evidence-based research has been done on its potential social benefits. AIM: To examine the association between consanguineous marriage and the risk of divorce or separation, polygyny, and survival of marriage in Jordan. SUBJECTS AND METHODS: Data were obtained from the 2018 Jordan Population and Family Health Survey, covering a nationally representative sample of ever-married women of reproductive age. Descriptive statistics, multiple logistic regression, and survival analysis techniques were used for data analysis. RESULTS: The prevalence of consanguineous marriage was found to be 27.5% in Jordan in 2018, while the prevalences of polygyny and divorced/separated rates were 4.4% and 4.7%, respectively. Both consanguineous and polygyny rates showed declining trends, but divorce/separation rate showed an increasing trend. Compared to non-consanguineous marriages, the risk of divorce/separation and polygyny were found to be lower among women with consanguineous marriage, while the survival of marriages was found to be higher for consanguineous marriages than for non-consanguineous marriages. CONCLUSIONS: Findings revealed that consanguinity has some social benefits as it plays protective roles against divorce or separation, polygyny and enhances the survival of marriages.


Assuntos
Consanguinidade , Divórcio/estatística & dados numéricos , Casamento/estatística & dados numéricos , Adolescente , Adulto , Feminino , Humanos , Jordânia , Pessoa de Meia-Idade , Fatores de Risco , Adulto Jovem
16.
Mol Biol Evol ; 36(3): 553-561, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30576522

RESUMO

Long-term suppression of recombination ultimately leads to gene loss, as demonstrated by the depauperate Y and W chromosomes of long-established pairs of XY and ZW chromosomes. The young social supergene of the Solenopsis invicta red fire ant provides a powerful system to examine the effects of suppressed recombination over a shorter timescale. The two variants of this supergene are carried by a pair of heteromorphic chromosomes, referred to as the social B and social b (SB and Sb) chromosomes. The Sb variant of this supergene changes colony social organization and has an inheritance pattern similar to a Y or W chromosome because it is unable to recombine. We used high-resolution optical mapping, k-mer distribution analysis, and quantification of repetitive elements on haploid ants carrying alternate variants of this young supergene region. We find that instead of shrinking, the Sb variant of the supergene has increased in length by more than 30%. Surprisingly, only a portion of this length increase is due to consistent increases in the frequency of particular classes of repetitive elements. Instead, haplotypes of this supergene variant differ dramatically in the amounts of other repetitive elements, indicating that the accumulation of repetitive elements is a heterogeneous and dynamic process. This is the first comprehensive demonstration of degenerative expansion in an animal and shows that it occurs through nonlinear processes during the early evolution of a region of suppressed recombination.


Assuntos
Formigas/genética , Expansão das Repetições de DNA , Recombinação Genética , Animais , Inversão Cromossômica , Cromossomos de Insetos , Genoma de Inseto , Masculino , Mutagênese Insercional
17.
Mol Ecol ; 29(19): 3622-3636, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32749006

RESUMO

The fire ant Solenopsis invicta exists in two alternate social forms: monogyne nests contain a single reproductive queen and polygyne nests contain multiple reproductive queens. This colony-level social polymorphism corresponds with individual differences in queen physiology, queen dispersal patterns and worker discrimination behaviours, all evidently regulated by an inversion-based supergene that spans more than 13 Mb of a "social chromosome," contains over 400 protein-coding genes and rarely undergoes recombination. The specific mechanisms by which this supergene influences expression of the many distinctive features that characterize the alternate forms remain almost wholly unknown. To advance our understanding of these mechanisms, we explore the effects of social chromosome genotype and natal colony social form on gene expression in queens sampled as they embarked on nuptial flights, using RNA-sequencing of brains and ovaries. We observe a large effect of natal social form, that is, of the social/developmental environment, on gene expression profiles, with similarly substantial effects of genotype, including: (a) supergene-associated gene upregulation, (b) allele-specific expression and (c) pronounced extra-supergene trans-regulatory effects. These findings, along with observed spatial variation in differential and allele-specific expression within the supergene region, highlight the complex gene regulatory landscape that emerged following divergence of the inversion-mediated Sb haplotype from its homologue, which presumably largely retained the ancestral gene order. The distinctive supergene-associated gene expression trajectories we document at the onset of a queen's reproductive life expand the known record of relevant molecular correlates of a complex social polymorphism and point to putative genetic factors underpinning the alternate social syndromes.


Assuntos
Formigas , Alelos , Animais , Formigas/genética , Herança Multifatorial , Polimorfismo Genético , Comportamento Social
18.
J Anat ; 236(3): 398-424, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31777085

RESUMO

A retractable larynx and adaptations of the vocal folds in the males of several polygynous ruminants serve for the production of rutting calls that acoustically announce larger than actual body size to both rival males and potential female mates. Here, such features of the vocal tract and of the sound source are documented in another species. We investigated the vocal anatomy and laryngeal mobility including its acoustical effects during the rutting vocal display of free-ranging male impala (Aepyceros melampus melampus) in Namibia. Male impala produced bouts of rutting calls (consisting of oral roars and interspersed explosive nasal snorts) in a low-stretch posture while guarding a rutting territory or harem. For the duration of the roars, male impala retracted the larynx from its high resting position to a low mid-neck position involving an extensible pharynx and a resilient connection between the hyoid apparatus and the larynx. Maximal larynx retraction was 108 mm based on estimates in video single frames. This was in good concordance with 91-mm vocal tract elongation calculated on the basis of differences in formant dispersion between roar portions produced with the larynx still ascended and those produced with maximally retracted larynx. Judged by their morphological traits, the larynx-retracting muscles of male impala are homologous to those of other larynx-retracting ruminants. In contrast, the large and massive vocal keels are evolutionary novelties arising by fusion and linear arrangement of the arytenoid cartilage and the canonical vocal fold. These bulky and histologically complex vocal keels produced a low fundamental frequency of 50 Hz. Impala is another ruminant species in which the males are capable of larynx retraction. In addition, male impala vocal folds are spectacularly specialized compared with domestic bovids, allowing the production of impressive, low-frequency roaring vocalizations as a significant part of their rutting behaviour. Our study expands knowledge on the evolutionary variation of vocal fold morphology in mammals, suggesting that the structure of the mammalian sound source is not always human-like and should be considered in acoustic analysis and modelling.


Assuntos
Antílopes/anatomia & histologia , Músculos Laríngeos/anatomia & histologia , Laringe/anatomia & histologia , Vocalização Animal/fisiologia , Acústica , Animais , Antílopes/fisiologia , Músculos Laríngeos/fisiologia , Laringe/fisiologia , Masculino , Prega Vocal/anatomia & histologia , Prega Vocal/fisiologia
19.
Oecologia ; 193(1): 15-26, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32201907

RESUMO

Animals are predicted to prefer high-quality over low-quality habitats, but adaptive habitat selection is less straightforward than often assumed. Preferences may improve only specific fitness metrics at particular spatial scales, with variation across time or between sexes. Preferences sometimes even reduce fitness. We investigated the context specificity of adaptive habitat selection, studying dickcissels (Spiza americana)-a polygynous songbird-as a model. From 2014 to 2015, we measured male and female habitat preferences at two scales (territories and landscape patches) on 21 grassland patches in Ringgold County, Iowa, USA. We tested whether preferences improved four fitness metrics-polygyny, avoidance of brood parasitism by brown-headed cowbirds (Molothrus ater), fledgling productivity, and offspring condition. Both sexes preferred territories where offspring attained superior condition and patches where parasitism was infrequent. Females preferred patches where nests produced more fledglings, and in 2014, males on preferred (i.e., early-established) territories attracted more mates and produced more fledglings. However, males on non-preferred (i.e., late-established) territories were more successful in 2015. This inconsistency may have arisen because females were abundant and nest-predation rates were low in May-June 2014, allowing early-settling males to produce many young. In 2015, however, females were more abundant and nests more successful later in the breeding season. Our results show that habitat preferences do not uniformly improve fitness, and some benefits differ between sexes. Moreover, preference-fitness relationships only manifest at specific scales, and annual variation in population and predation dynamics can limit consistency. Detecting adaptive habitat selection thus requires multi-year measurements and careful consideration of relevant scales.


Assuntos
Passeriformes , Aves Canoras , Animais , Ecossistema , Feminino , Pradaria , Masculino , Comportamento de Nidação , Comportamento Predatório
20.
Afr J Reprod Health ; 24(4): 198-212, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34077084

RESUMO

Using a systematic literature review approach, this paper focused on the role of polygyny in the spread of HIV/AIDS in sub-Saharan Africa (SSA) countries. The widespread practice of polygyny is one feature of many SSA contexts that may be relevant to understanding patterns of HIV prevalence. Building on the conflicting studies on the importance of polygyny, this study investigated whether or not polygyny is a conduit for elevating HIV transmission in SSA countries. Findings showed that polygyny as an institution is perhaps less of a concern; rather the implication that men and women who are in polygamous relationships are also more likely to engage in extra-marital sex - raises secondary questions about their patterns of sexual networking and concurrent sexual partnerships. The findings however show that polygyny amplifies risky sexual behaviours such as sexual networking and concurrent sexual partnerships, all of which were found to be significantly associated with the risk of HIV transmission. This demonstrates that targeting risky sexual behaviours in a broader marital context may be more important for HIV risk reduction than targeting polygyny as an institution.


Assuntos
Infecções por HIV/transmissão , Casamento/etnologia , África Subsaariana , Feminino , Infecções por HIV/etnologia , Humanos , Masculino , Casamento/psicologia
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