Family Structure and Reproductive Health Decision Making among the Ogu of Southwestern Nigeria: A Qualitative Study

This study examines the structure of the Ogu family and its influence on reproductive health decision-making using a qualitative approach. Data were sourced through nine focus groups organized in the study area among married men and women. The data reveal that the family structure in the study area is changing, although the dominant pattern remains extended. The findings of the study suggest that there are on-going internal transformations that tend to enhance gender equity in reproductive health decision-making between husbands and wives. These changes may be attributed to the widespread influence of western culture and the spread of education in the study population, which are necessary concomitants of economic, political and cultural changes taking place in the society.Cet article examine la structure de la famille Ogu et son influence sur la prise de d\ue9cision en mati\ue8re de sant\ue9 de la reproduction. Les donn\ue9es utilis\ue9es sont des donn\ue9es qualitatives obtenues \ue0 partir de 9 "Focus Group" organis\ue9s entre hommes et femmes mari\ue9es du milieu d'\ue9tude. Les donn\ue9es montrent que la structure de la famille dans ce milieu d'\ue9tude \ue9volue bien que le type dominant reste la famille \ue9largie. Les r\ue9sultats de l'\ue9tude montrent que des transformations internes tendant \ue0 promouvoir l'\ue9galit\ue9 entre les genres en mati\ue8re de prise de d\ue9cision concernant la sant\ue9 de la reproduction entre \ue9poux et \ue9pouses sont entrain de s'op\ue9rer. Ces \ue9volutions peuvent \ueatre dues par l'influence croissante de la culture occidentale et la g\ue9n\ue9ralisation de l'\ue9ducation dans la population \ue9tudi\ue9e qui accompagnent n\ue9cessairement les transformations \ue9conomiques, politiques et culturelles en cours dans la soci\ue9t\ue9

Effects of Pleistocene climate changes on species ranges and evolutionary processes in the Neotropical Atlantic Forest

The effects of global glaciations on the distribution of organisms is an essential element of many diversification models. However, the empirical evidence supporting this idea is mixed, in particular with respect to explaining tropical forest evolution. In the present study, we evaluated the impacts of range shifts associated with Pleistocene global glacial cycles on the evolution of tropical forests. In particular, we tested the predictions: (1) that population genetic structure increases with fragmentation variation between the present and the Last Glacial Maximum (LGM) and also (2) with geographical range instability; and (3) that genetic diversity increases with range stability and (4) decreases with fragmentation variation between periods. To address our predictions, we studied population genetic structures and modelled present and past distributions of 15 Atlantic Forest (AF) endemic birds. Afterwards, we evaluated the relationship of population genetic parameters with metrics of species range shifts between the present and the LGM. We found that geographical ranges of AF birds changed in concert with Pleistocene glacial cycles but, unexpectedly, our findings suggest the novel idea that ranges during glacial maxima were slightly larger on average, as well as equally fragmented and displaced from the interglacial ranges. Our findings suggest that range shifts over the late Pleistocene impacted on the diversification of forest organisms, although they did not show that those range shifts had a strong effect. We found that a combination of fragmentation variation across time, small current range size, and range stability increased population genetic structure. However, neither fragmentation, nor range stability affected genetic diversity. Our study showed that evolutionary responses to range shifts across AF birds have a high variance, which could explain the mixed support given by single-species studies to the action of Pleistocene range shifts on population evolution.Fil: Cabanne, Gustavo Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Calderón, Pablo Luciano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Trujillo Arias, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Flores, Pamela. Universidad Nacional de General Sarmiento; ArgentinaFil: Pessoa, Rodrigo. Universidade Estadual de Montes Claros; BrasilFil: d'Horta, Fernando M.. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Miyaki, Cristina Y.. Universidade de Sao Paulo; Brasi

Dispersal and population structure at different spatial scales in the subterranean rodent Ctenomys australis

This study was funded by grants from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP5838), Agencia de Promoción Científica y Tecnológica de la Argentina (PICTO1-423, BID-1728/OC-AR), and the programme ECOS-Sud France/Argentina (A05B01).Background: The population genetic structure of subterranean rodent species is strongly affected by demographic (e.g. rates of dispersal and social structure) and stochastic factors (e.g. random genetic drift among subpopulations and habitat fragmentation). In particular, gene flow estimates at different spatial scales are essential to understand genetic differentiation among populations of a species living in a highly fragmented landscape. Ctenomys australis (the sand dune tuco-tuco) is a territorial subterranean rodent that inhabits a relatively secure, permanently sealed burrow system, occurring in sand dune habitats on the coastal landscape in the south-east of Buenos Aires province, Argentina. Currently, this habitat is threatened by urban development and forestry and, therefore, the survival of this endemic species is at risk. Here, we assess population genetic structure and patterns of dispersal among individuals of this species at different spatial scales using 8 polymorphic microsatellite loci. Furthermore, we evaluate the relative importance of sex and habitat configuration in modulating the dispersal patterns at these geographical scales. Results: Our results show that dispersal in C. australis is not restricted at regional spatial scales (similar to 4 km). Assignment tests revealed significant population substructure within the study area, providing support for the presence of two subpopulations from three original sampling sites. Finally, male-biased dispersal was found in the Western side of our study area, but in the Eastern side no apparent philopatric pattern was found, suggesting that in a more continuous habitat males might move longer distances than females. Conclusions: Overall, the assignment-based approaches were able to detect population substructure at fine geographical scales. Additionally, the maintenance of a significant genetic structure at regional (similar to 4 km) and small (less than 1 km) spatial scales despite apparently moderate to high levels of gene flow between local sampling sites could not be explained simply by the linear distance among them. On the whole, our results support the hypothesis that males disperse more frequently than females; however they do not provide support for strict philopatry within females.Publisher PDFPeer reviewe

Discriminant analysis of principal components and pedigree assessment of genetic diversity and population structure in a tetraploid potato panel using SNPs

The reported narrow genetic base of cultivated potato (Solanum tuberosum) can be expanded by the introgression of many related species with large genetic diversity. The analysis of the genetic structure of a potato population is important to broaden the genetic base of breeding programs by the identification of different genetic pools. A panel composed by 231 diverse genotypes was characterized using single nucleotide polymorphism (SNP) markers of the Illumina Infinium Potato SNP Array V2 to identify population structure and assess genetic diversity using discriminant analysis of principal components (DAPC) and pedigree analysis. Results revealed the presence of five clusters within the populations differentiated principally by ploidy, taxonomy, origin and breeding program. The information obtained in this work could be readily used as a guide for parental introduction in new breeding programs that want to maximize variability by combination of contrasting variability sources such as those presented here.Fil: Deperi, Sofía Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Tagliotti, Martin Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Bedogni, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Manrique Carpintero, Norma C.. Michigan State University; Estados UnidosFil: Coombs, Joseph. Michigan State University; Estados UnidosFil: Zhang, Ruofang. Inner Mongolia University; ChinaFil: Douches, David. Michigan State University; Estados UnidosFil: Huarte, Marcelo Atilio. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentin

Weak Lensing Peaks in Simulated Light-Cones: Investigating the Coupling between Dark Matter and Dark Energy

In this paper, we study the statistical properties of weak lensing peaks in light-cones generated from cosmological simulations. In order to assess the prospects of such observable as a cosmological probe, we consider simulations that include interacting Dark Energy (hereafter DE) models with coupling term between DE and Dark Matter. Cosmological models that produce a larger population of massive clusters have more numerous high signal-to-noise peaks; among models with comparable numbers of clusters those with more concentrated haloes produce more peaks. The most extreme model under investigation shows a difference in peak counts of about $20\%$ with respect to the reference $\mathrm{\Lambda}$CDM model. We find that peak statistics can be used to distinguish a coupling DE model from a reference one with the same power spectrum normalisation. The differences in the expansion history and the growth rate of structure formation are reflected in their halo counts, non-linear scale features and, through them, in the properties of the lensing peaks. For a source redshift distribution consistent with the expectations of future space-based wide field surveys, we find that typically seventy percent of the cluster population contributes to weak-lensing peaks with signal-to-noise ratios larger than two, and that the fraction of clusters in peaks approaches one-hundred percent for haloes with redshift z$\leq$0.5. Our analysis demonstrates that peak statistics are an important tool for disentangling DE models by accurately tracing the structure formation processes as a function of the cosmic time.Comment: accepted in MNRAS, figures improved and text update

L´impact des aires protégées et des utilisations anthropogènes du sol sur la regeneration des terrains boisés à Acacia dans l´est du Burkina Faso

Regeneration success, persistence strategies (seedlings vs. coppicing), and population trend of Acacia spp. were tested under two land-use regimes in eastern Burkina Faso: (i) protected areas shielded to livestock grazing pressure, to logging, and using early annual fire as a management system; (ii) areas with high human impact (heavily and extensive livestock grazing, harvesting for wood and for medicinal plants). Generally, a good regeneration rate of Acacia species was observed in protected areas and a poor regeneration rate in areas with high human impact. Nevertheless, some species affiliated to the subgenus Aculeiferum as A. dudgeoni and A. polyacantha showed a good regeneration under both land use regimes. Juvenile plants less than 25 cm height of A. dudgeoni and A. gourmaensis increased by 116 to 50 % in areas with human impact as compared to their populations in protected areas. With SCD slopes varying from –0.40 to -0.70, the protected Acacia woodland displayed a stable population structure due to abundance of recruitment, and coppicing persistence (more common in the subgenus Aculeiferum) favoured by early annual fire. Consequently, the protected areas are favourable for Acacia woodland regeneration. Conversely, SCD slopes are positive or close to zero in areas of anthropogenic regime and showed a declining population, especially more marked with the subgenus Acacia due to permanent seed and seedling removal by livestock grazing. Nevertheless, the number of seedlings of some species was higher in areas under human pressure than in protected areas, especially for the subgenus Aculeiferum, improving the genetic variability and thus the long-term maintenance of the population. Key words: Acacia, early fire, land use, sudano-sahelien zoneLe statut de la régénération, les stratégies de persistance et la dynamique des Acacia spp. ont été évalués suivant deux modes d’utilisation dans la région est du Burkina Faso: (i) les zones protégées soustraites du pâturage extensif et de la coupe du bois, mais sont parcourues annuellement par des feux précoces ; (ii) les zones à forte impact anthropique (fort pâturage extensif, exploitations humaines diverses). En général, les zones protégées montrent un taux de régénération élevé des Acacia spp. alors que les zones anthropogéniques présentent une faible régénération. Néanmoins, certaines espèces affiliées au sous genre Aculeiferum comme A. dudgeoni et A. polyacantha montrent une bonne régénération dans les deux modes d’utilisation des terres. La population juvénile de moins de 25 cm de hauteur des espèces tel que A. dudgeoni et A. gourmaensis est 116 à 50 % plus élevée dans les zones anthropisées que dans les zones protégées. Avec des pentes de régression variant entre -0.40 à -0.70 dans les zones protégées, les populations présentent une structure stable due à l’abondance des plantules, et des rejets de souches maintenues par les feux précoces (plus fréquent dans le sous genre Aculeiferum). Par conséquent, les zones protégées sont plus favorables à la régénération des formations d’Acacia. A l’opposé, les pentes de régression sont positives ou proche de 0 dans les zones anthropisées montrant des populations peu stables particulièrement pour le sous genre Acacia à cause du prélèvement des semences et des plantules due au pâturage extensif. Néanmoins, les plantules issues de la germination de certaines espèces du sous Aculeiferum sont plus nombreuses dans les zones anthropisées que dans les zones protégées et pourraient améliorer la variabilité génétique pour la conservation à long termes des peuplements. Key words: Acacia, feux précoces, pâturage, utilisation des terres, zone soudano-sahélienn

Population structure of the broad-snouted caiman (Caiman latirostris) in natural and man-made water bodies associated with a silvicultural landscape

The broad-snouted caiman (Caiman latirostris) is a South American crocodilian with a wide geographical distribution. Water bodies originally occupied by the species have suffered extreme anthropogenic pressure; however, the broad-snouted caiman has a high adaptive capacity to colonize man-made habitats such as decanting pounds and artificial reservoirs for agriculture or livestock. In this context, the present study aimed at identifying the population structure of the broad-snouted caiman in a silvicultural landscape in southeastern Brazil. Fifty-two caimans of various classes were captured with baited traps and steel cable snares at night. The estimated population size was 51 individuals. The population density was estimated to be 2.6 individuals/ha with a linear density of 11.3 individuals/km. The intermediate values of linear density estimates herein compared with other areas, suggesting that silvicultural landscapes can be relevant for broadsnouted caiman conservation. Therefore, the role of silvicultural landscapes in crocodilian conservation should be taken into consideration for environmental certification processes related to forestry in the Neotropics.Fil: Marques, Thiago Simon. Universidade de Sao Paulo; BrasilFil: Bassetti, Luís Antonio Bochetti. Universidade de Sao Paulo; BrasilFil: Lara, Neliton Ricardo Freitas. Universidade de Sao Paulo; BrasilFil: Millan, Cristian Honora. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Piña, Carlos Ignacio. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Verdade, Luciano Martins. Universidade de Sao Paulo; Brasi

Modelos poblacionales de dos sexos aplicados a especies poligínicas

En este trabajo revisamos un modelo poblacional de dos sexos enfocándolo en la relación entre demografía y estructura social para una especie poligínica. El modelo fue aplicado a la población de elefantes marinos del sur de Península Valdés, una población que muestra tendencias contrastantes en dos subunidades con distinta estructura social. Este enfoque provee un marco general que permite incluir variables sociales en la dinámica de poblaciones como una extensión del modelo lineal estándar y aporta una herramienta al análisis de la dinámica identificando las influencias relativas de cada sexo.We review a two-sex population model and focus on the link between demography and social structure in a polygynous species. The model was applied to the southern elephant seal population of Península Valdés, one that shows contrasting trends in two demographic subunits with distinct social structure. This approach provides a general framework to include social variables into population dynamics. This perspective extends the scope of standard lineal models and adds a tool that identifies the relative effect of changes in number of one sex on the population.Fil: Ferrari, Mariano Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Campagna, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Wildlife Conservation Society; Estados Unido

Explaining cooperative groups via social niche construction

Cooperative behaviours can be defined as those that benefit others at an apparent cost to self. How these kinds of behaviours evolve has been a topic of great interest in evolutionary biology, as the Darwinian paradigm seems to suggest that nature will be “red in tooth and claw” and that we would not expect one organism to evolve to help another. The evolution-of-cooperation literature has therefore generally been about showing how the altruism involved in these cases is only apparent (see Bergstrom 2002 for an excellent review). Consider kin selection, in which interactions are more likely to occur between related individuals. The cost of altruism to the individual is real but, having identified the correct score-keeping level as the genetic one, it turns out that the cooperative act is not costly but profitable. More generally, successful explanations for cooperation rely on the presence of a population structure that clusters cooperators together, such that they enjoy the benefits of each others' actions. However, the question that has been left largely unaddressed is how does this structure itself evolve? If we want to really explain why organisms cooperate, then we need to explain not just their adaptation to their social environment, but how they came to live in that environment. Recent work by Powers (2010) and Powers et al. (in press) has addressed this question. They show that social behaviour can exert indirect selection pressure on population structure-modifying traits, causing individuals to adaptively modify their population structure to support greater cooperation. Moreover, they argue that any component of selection on structure-modifying traits that is due to social behaviour must be in the direction of increased cooperation; that component of selection cannot be in favour of the conditions for greater selfishness. Powers et al. then examine the conditions under which this component of selection on population structure exists. They argue that not only can population structure drive the evolution of cooperation, as in classical models, but that the benefits of greater cooperation can in turn drive the evolution of population structure: a positive feedback process that they refer to as social niche construction (after Odling-Smee et al. 2003). Maynard Smith and Szathmary (1995) note that most of the big unanswered questions in biology are not about how a particular behaviour is selected for at one level of organization but about the emergence of whole new levels of organization, e.g., the transition from single- to multi-celled organisms, or from solitary insects to eusocial colonies. Any satisfactory account of these transitions must explain how the individuals came to live in a population structure that supported high degrees of cooperation, as well as showing that cooperation is individually advantageous given that structure. The social niche construction process identified by Powers et al. can explain some of the major transitions, by showing how a new selective level can begin through evolution of individual characters, such as group size preference or dispersal tendency. The potential emergence of reliable cooperation via the co-evolution of individual cooperative and population-structuring behaviours demonstrates that groups of cooperating agents can create an environment in which they become so “locked in” to their group identity that the group warrants redescription as an individual in its own right. Consider the move from independent protozoans, to an intermediate cooperative stage as in slime moulds, to fully multi-cellular animals. Such creation of population structures that support cooperation parallels negotiation of a social contract. What are the philosophical implications of this perspective for understanding and explaining human social behaviour? On the one hand, it gives respectability and unique explanatory value to group-selectionist accounts. Explaining the origin of within-group cooperation and the origin of the groups themselves become part of the same project, which in turn means that we cannot understand social and cooperative behaviour in humans without understanding human population-structuring traits, e.g., living in family groups, group fission-fusion behaviours, migratory behaviours, etc. What will the explanations we seek look like? de Pinedo and Noble (2008) have argued that the description of evolved behaviour cannot be exclusively in mechanistic terms: we need both explanations that focus on an agent’s interaction with its environment, and explanations that focus on the physical or computational enabling conditions of such an interaction. In a context in which what counts as an agent is taken for granted, de Pinedo and Noble argue that both agent and sub-agent level explanations will be required. The perspective being outlined here forces an expansion of that position and reminds us that agency is not to be taken for granted; that it emerges from a lower level of organization after a history of selection brings simpler entities together in a coherent cooperative whole. The implication is that truly multi-level explanations will be necessary in the area of social behaviour. We explain the origin of the multi-cellular organism as the result of a cooperative merger of single-celled organisms, and we explain the origin of a super-organism such as an ant colony in a similar way. At each transition, the autonomous agents of the previous level become component mechanisms in the next, but no explanatory level can be entirely done away with. A human being is an example of a multi-cellular organism with a highly developed social aspect, occupying an intermediate point between radical individual independence and total group cohesion. To fully explain human behaviour, we need to know about the cellular machinery that enables personal-level agency. But we also need to know how human machinery fits together into families, communities and nations that will, at least partially, have their own emergent goals and purposes: “partially” because we are not yet a super-organism, of course. In conclusion, the perspective we outline suggests a view of the social contract as not at all unique to Hobbesian rational agents who have become tired of an insecure and violent lifestyle. Instead the ongoing negotiation of the social contract amongst ourselves can be seen as echoing earlier, now-successfully-concluded negotiations between the entities that became our genes and then our cells