Phenotypic plasticity in size of ant-domatia

International audienceAnt-plants produce hollow structures called domatia to host protecting ants. Although size variation in domatia is well documented between related species, intraspecific variation is little explored. The central African ant-plant Barteria dewevrei exibits strong variation in domatium size, giving the opportunity to explore the mechanism underlying variation in a mutualistic trait. We showed that domatium size in Barteria dewevrei varies between sites. We transplanted individual plants between two sites in Gabon where plants have different domatium sizes. Domatium size of transplanted plants changed, revealing that variation in this mutualistic trait is driven by phenotypic plasticity. The two sites differed in their environmental conditions: highland open savanna on sandy soil vs lowland closed tropical rain forest on sandy-loam soil. However, as stomatal density and δ 13 C of leaves did not differ between sites or between branches produced before and after transplantation, we have no cue on the role of abiotic stress (such as light intensity and water availability) in domatium size variation. As the obligate Tetraponera ant symbionts are too large to fit in the small domatia, variation of the mutualistic trait in response to environmental change through phenotypic plasticity may impact this specialized mutualism

Congeneric mutualist ant symbionts (Tetraponera , Pseudomyrmecinae) differ in level of protection of their myrmecophyte hosts (Barteria , Passifloraceae)

International audienceBarteria fistulosa and B. dewevrei, central African rain-forest trees, provide nesting cavities for Tetraponera aethiops and T. latifrons ants, respectively, which protect them against herbivores. To compare protection efficiency between these two symbioses, for 20 plants of each species in two sites in Gabon we measured the time elapsed before ants reached a focal leaf, for host leaves that were undisturbed, damaged (cut with scissors) or subjected to slight vibration (mimicking such damage), and for damaged leaves of the non-host Barteria species. Tetraponera aethiops displayed stronger protective behaviour than did T. latifrons. Time to reach a damaged host leaf (4.5 ± 2.6 min, mean ± SD) did not differ significantly from time to reach a leaf subjected to slight vibration (5.2 ± 3.0 min) for T. aethiops, but response to a leaf subjected to slight vibration (9.5 ± 1.9 min) was significantly slower than that to a damaged leaf (7.8 ± 1.9 min) for T. latifrons. The faster response of T. aethiops to slight vibration may have masked a response of this species to chemical signalling. Both ants reached damaged host leaves faster than damaged leaves of the non-host Barteria sp., indicating host plant specificity in ant responses

Eau, hygiène, assainissement et santé dans les quartiers précaires à Nouakchott (Mauritanie) : contribution à l’approche écosanté à Hay Saken

Dans les grandes villes africaines à l’instar de Nouakchott, plusieurs facteurs rendent difficiles la maîtrise de la gestion de l’assainissement urbain et l’accès à l’eau potable. Les populations s’installent sans avoir la possibilité d’accéder aux services urbains. C’est notamment le cas de nombreux quartiers spontanés et précaires très peuplés comme Hay Saken où le manque de services de base tels que l’eau et l’assainissement est une problématique très complexe liant la santé et l’environnement. Dans le cadre d’une expérience en approche écosanté menée de janvier 2010 à décembre 2011, des enquêtes (ménage et géographique) ont été réalisées pour évaluer l’impact de l’hygiène de base sur le développement des maladies diarrhéiques à Hay Saken. Dans l’ensemble, les résultats mettent en exergue l’ampleur de la vulnérabilité socio-économique, environnementale et sanitaire. Ils montrent que 59,7% des enquêtés associent leurs problèmes de santé à la dégradation de leur cadre de vie cerné par ailleurs grâce à une cartographie environnementale. La diarrhée a été déclarée chez 10,4% (23/221) des ménages et chez 13,5% (42/311) des enfants de moins de 5 ans. Les facteurs de risque associés à la survenue des diarrhées sont les intoxications alimentaires (62,5%), la qualité de l’eau de boisson (29,1%) et la mauvaise hygiène domestique (8,3%). Toutes ces causes citées semblent résulter de la carence en services de base : 94,5% des ménages recourent à l’eau vendue (charretiers, revendeurs sur place), 44,8% ne disposent pas de latrines, 88,5% des familles possédant une fosse septique font une vidange manuelle, 78,7% évacuent leurs eaux usées sur les voies publiques et 42,5% déversent leurs ordures sur des dépôts sauvages. Avec le manque de services de base, la persistance de telles pratiques risque d’accroître les problèmes environnementaux et sanitaires. (La menace du péril fécal)appelle alors à une prise de conscience collective et à un changement de comportement dans les pratiques. À la suite de l’atelier de restitution des résultats de la recherche à la population bénéficiaire, les solutions préconisées ont fait l’objet d’une stratégie de réduction des risques sanitaires liés à l’eau, l’assainissement et l’hygiène de base par la sensibilisation et l’éducation

Evolution and Conservation of Central African Biodiversity: Priorities for Future Research and Education in the Congo Basin and Gulf of Guinea

The tropical forests of the Congo Basin and Gulf of Guinea harbor some of the greatest terrestrial and aquatic biological diversity in the world. However, our knowledge of the rich biological diversity of this region and the evolutionary processes that have shaped it remains limited, as is our understanding of the capacity for species to adapt or otherwise respond to current and projected environmental change. In this regard, research efforts are needed to increase current scientific knowledge of this region's biodiversity, identify the drivers of past diversification, evaluate the potential for species to adapt to environmental change and identify key populations for future conservation. Moreover, when evolutionary research is combined with ongoing environmental monitoring efforts, it can also provide an important set of tools for assessing and mitigating the impacts of development activities. Building on a set of recommendations developed at an international workshop held in Gabon in 2011, we highlight major areas for future evolutionary research that could be directly tied to conservation priorities for the region. These research priorities are centered around five disciplinary themes: (1) documenting and discovering biodiversity; (2) identifying drivers of evolutionary diversification; (3) monitoring environmental change; (4) understanding community and ecosystem level processes; (5) investigating the ecology and epidemiology of disease from an evolutionary perspective (evolutionary epidemiology). Furthermore, we also provide an overview of the needs and priorities for biodiversity education and training in Central Africa.Additional co-authors: Katy Morgan, Stephan Ntie, Thomas B Smith, John P Sullivan, Erik Verheyen, and Mary K Gonde

Evolution and conservation of Central African biodiversity: priorities for future research and education in the Congo Basin and Gulf of Guinea

The tropical forests of the Congo Basin and Gulf of Guinea harbor some of the greatest terrestrial and aquatic biological diversity in the world. However, our knowledge of the rich biological diversity of this region and the evolutionary processes that have shaped it remains limited, as is our understanding of the capacity for species to adapt or otherwise respond to current and projected environmental change. In this regard, research efforts are needed to increase current scientific knowledge of this region's biodiversity, identify the drivers of past diversification, evaluate the potential for species to adapt to environmental change and identify key populations for future conservation. Moreover, when evolutionary research is combined with ongoing environmental monitoring efforts, it can also provide an important set of tools for assessing and mitigating the impacts of development activities. Building on a set of recommendations developed at an international workshop held in Gabon in 2011, we highlight major areas for future evolutionary research that could be directly tied to conservation priorities for the region. These research priorities are centered around five disciplinary themes: (1) documenting and discovering biodiversity; (2) identifying drivers of evolutionary diversification; (3) monitoring environmental change; (4) understanding community and ecosystem level processes; (5) investigating the ecology and epidemiology of disease from an evolutionary perspective (evolutionary epidemiology). Furthermore, we also provide an overview of the needs and priorities for biodiversity education and training in Central Africa

Evolution and conservation of Central African Biodiversity : priorities for future research and education in the Congo basin and Gulf of Guinea

The tropical forests of the Congo Basin and Gulf of Guinea harbor some of the greatest terrestrial and aquatic biological diversity in the world. However, our knowledge of the rich biological diversity of this region and the evolutionary processes that have shaped it remains limited, as is our understanding of the capacity for species to adapt or otherwise respond to current and projected environmental change. In this regard, research efforts are needed to increase current scientific knowledge of this region's biodiversity, identify the drivers of past diversification, evaluate the potential for species to adapt to environmental change and identify key populations for future conservation. Moreover, when evolutionary research is combined with ongoing environmental monitoring efforts, it can also provide an important set of tools for assessing and mitigating the impacts of development activities. Building on a set of recommendations developed at an international workshop held in Gabon in 2011, we highlight major areas for future evolutionary research that could be directly tied to conservation priorities for the region. These research priorities are centered around five disciplinary themes: (1) documenting and discovering biodiversity; (2) identifying drivers of evolutionary diversification; (3) monitoring environmental change; (4) understanding community and ecosystem level processes; (5) investigating the ecology and epidemiology of disease from an evolutionary perspective (evolutionary epidemiology). Furthermore, we also provide an overview of the needs and priorities for biodiversity education and training in Central Africa