Sex bias in biopsy samples collected from free-ranging dolphins

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in European Journal of Wildlife Research 56 (2010): 151-158, doi:10.1007/s10344-009-0299-7.Biological samples of free-ranging dolphins are increasingly used to gain information on population structure and ecology. In small cetaceans, the gender of individuals usually cannot be determined at sea, and population sex ratio has to be inferred indirectly. We used molecular sexing to determine the gender of 340 biopsy samples of bottlenose dolphins, Tursiops truncatus, spotted dolphins, Stenella frontalis, and common dolphins, Delphinus delphis, collected around the Azores and Madeira. Sex ratio was globally skewed in favor of males, and differed between species and archipelagos. Skew was probably influenced by the selectivity of biopsy collectors and seasonal or year-round predominance of males in natural populations. Skew was also influenced by sampling duration and intensity. In the Azores, when several samples were successively collected within the same group, the proportion of female samples decreased as a function of sample order. This trend indicated a tendency for females to increasingly avoid the boat while samples were being collected. It showed that males and females reacted differently to the perturbation caused by the biopsy sampling process (i.e. sample collection and driving style).Portuguese Foundation for Science and Technology (FCT) and the FEDER program for funding the CETAMARH (POCTI/BSE/38991/01) and the GOLFINICHO (POCI/BIA-BDE/61009/2004) projects, S.Q.'s post-doctoral grants (IMAR/FCT- PDOC-006/2001-MoleGen and SFRH/BPD/19680/2004), M.A.S.'s doctoral (SFRH/BD/8609/2002) and post-doctoral (SFRH/BPD/29841/2006) grants, S.M.'s investigation assistant grant (CETAMARHII/POCTI/BSE/38991/2001) and I.C.'s investigation assistant grants (IMAR/FCT/GOLFINICHO/001/2005 and IMAR/FCT/GOLFINICHO/004/2006). FCT for its pluri-annual funding to Research Unit #531 and the EU funded program Interreg IIIb for funding the MACETUS project (MAC/4.2/M10) as well as R.P. and S.M.’s grants (IMAR/INTERREGIIIb/MACETUS/MAC1/2)

Intérêts et limites de l'approche moléculaire pour aborder la biogéographie et la spéciation : l'exemple de quelques Mammifères d'Afrique tropicale

Among the sciences which study the patterns of diversification and distribution of organisms in space and time, biogeography investigates the history of biota based on organism distributions, and phylogeography focuses on one taxa at the time. Biogeographic studies carried out in tropical areas have led to a series of evolutionary hypotheses about faunal diversification and speciation, such as the refuge, the riverine barrier, and the environmental gradient theories. In the present work, we attempt to test these hypotheses by applying the molecular approach to selected mammalian taxa (Insectivora, Rodentia, and Primates) from tropical Africa. We try to estimate the interests and limits of mitochondrial DNA sequencing, the most widely used molecular technique in evolutionary biology, for addressing questions about faunal evolution.First, we constructed a molecular phylogeny of taxa we intended to use for phylogeographic studies, in order to ascertain their monophyly and calibrate a molecular clock for divergence time estimates. Second, we analysed and compared the phylogeographic patterns of four forest-dwelling small mammal species and one primate super-species. Third, we evaluated the evolutionary processes involved in the speciation of cercopithecine primates, by testing their geographic mode of speciation and reconstructing evolutionary scenarios for some life-history traits.The comparison of our molecular-based phylogenies with other sources of information confirms that gene history is not necessarily the same as organism history. Thus, mitochondrial DNA should be studied in combination with other independent data, such as nuclear genes, morphology, ecology and behaviour. The acquisition of reliable phylogenies is a pre-requisite for the study of speciation. In the case of the Cercopithecini, our results suggest that speciation has been predominantly allopatric and driven by Miocene and Pliocene vicariance events. The obtained phylogeographic patterns consistently suggest a role of Pliocene and Pleistocene vicariance events in the intra-specific diversification of small mammals. All phylogeographic patterns are different, which may be explained by differences in initial geographic and temporal conditions, or by different responses to the same events. However, there is a certain degree of consistency between these patterns and the faunal areas defined for the central African forest. The examination of additional taxa could potentially unveil a general picture despite individual differences.Parmi les approches qui visent à déterminer la façon dont les organismes se diversifient dans le temps et dans l'espace, la biogéographie tente de reconstruire l'histoire des peuplements à partir des distributions des taxons, tandis que la phylogéographie analyse l'évolution d'une lignée à la fois. Dans cette étude, nous nous sommes proposés de tester les hypothèses biogéographiques formulées pour la faune tropicale (théorie des refuges, des barrières fluviales, des gradients environnementaux...), en appliquant l'approche moléculaire à quelques taxons de Mammifères africains (Insectivores, Rongeurs, Primates). Nous avons cherché à déterminer l'apport et les limites de la technique moléculaire la plus couramment employée en biologie évolutive : le séquençage d'ADN mitochondrial. Nous avons d'abord tenté d'obtenir une phylogénie moléculaire de quelques taxons potentiellement intéressants pour la biogéographie, dans le but de vérifier leur monophylie et de calibrer une horloge moléculaire. Puis, nous avons recherché et comparé les schémas phylogéographiques de quatre espèces de petits mammifères forestiers et d'une super-espèce de primates. Enfin, nous nous sommes intéressés aux processus évolutifs impliqués dans la spéciation. Nous avons évalué le mode géographique de spéciation et l'évolution de quelques traits d'histoire de vie chez les primates de la tribu des Cercopithecini. Nos résultats phylogénétiques confirment que l'histoire des gènes n'est pas forcément celle des taxons et qu'il est important de prendre en compte plusieurs sources d'information indépendantes, telles que des gènes non liés sur la même molécule, la morphologie, l'écologie, et le comportement. L'étude des modalités de la spéciation, qui est tributaire de la fiabilité des analyses phylogénétiques, indique une prédominance de l'allopatrie et des événements de vicariance du Miocène et du Pliocène chez les Cercopithecini. Enfin, les analyses phylogéographiques ont révélé quatre scénarios phylogéographiques différents pour les quatre modèles retenus, ce qui peut refléter soit des distributions initiales différentes, soit une réponse différentielle aux mêmes événements selon les taxons. Ces scénarios présentent une certaine concordance avec les régions fauniques définies pour les forêts d'Afrique centrale, mais suggèrent que les événements de divergence intra-spécifique remonteraient au Plio-Pleistocène et seraient donc beaucoup plus anciens que les derniers épisodes de fragmentation de la forêt liés aux cycles glaciaires

Social influence on feeding behaviour development in young cercopithecines

WOS:000078060700015International audience[No abstract

Feeding behaviour development in young cercopithecines

WOS:000078060700016International audience[No abstract

Seed eating in elephant dung by two large mammals in the Congo Republic

WOS:000182232700005International audienceIn a Congolese forest clearing visited regularly by a number of elephants, a resident group of sitatungas and three visiting groups of red river hogs were observed to forage on elephant dung for seeds. This accounted for 33% of feeding time in hogs and 20% in sitatungas. Seeds taken from elephant dung constitute a significant food resource and foraging in dung seems to be a widespread phenomenon in the region. This post-dispersal seed predation has no effect on forest regeneration because in clearings elephant dung are deposited where seeds do not germinate due to the soil hydromorphy and trampling. When dung are deposited in swamp clearings, elephants cannot be considered as efficient seed dispersers.Au Congo, dans une clairière forestière visitée par de nombreux éléphants, des sitatun gas appartenant à un groupe résident et des potamochères issus de trois groupes visiteurs fouillent régulièrement les crottins d'éléphants pour y prélever des graines. Ce comportement représente 33% des activités alimentaires des potamochères et 20% de celles des sitatungas. Ces graines constituent une source alimentaire significative et l'affouragement dans les crot tins semble un comportement répandu dans la région. Cette prédation de graines après disper sion n'a pas d'effet sur la régénération forestière car les crottins d'éléphants sont déposés dans des zones où les graines ne germent pas en raison de l'hydromorphie et du piétinement du sol. Lorsque les éléphants déposent leurs crottins dans des clairières marécageuses, ils ne peuvent être considérés comme des disperseurs efficaces de graines. SUMMARY In a Congolese forest clearing visited regularly by a number of elephants, a resident group of sitatungas and three visiting groups of red river hogs were observed to forage on ele phant dung for seeds. This accounted for 33% of feeding time in hogs and 20% in sitatungas. Seeds taken from elephant dung constitute a significant food resource and foraging in dung seems to be a widespread phenomenon in the region. This post-dispersal seed predation has no effect on forest regeneration because in clearings elephant dung are deposited where seeds do not germinate due to the soi! hydromorphy and trampling. When dung are deposited in swamp clearings, elephants cannot be considered as efficient seed dispersers

De l’utilisation de séquences d’ADN mitochondrial pour l’identification des espèces au sein de la tribu des Cercopithecini

International audienceL’ADN mitochondrial est actuellement utilisé comme un outil pour identifier l’espèce et l’originegéographique de spécimens d’origine inconnue, dans le but d’améliorer le succès des programmes de réintroductionet de reproduction en captivité. Afin d’évaluer cette possibilité dans le cas des Primates de latribu des Cercopithecini, nous avons analysé les relations phylogénétiques entre séquences partiellesd’ARN-r 16S de 18 spécimens de la super-espèce Cercopithecus cephus. L’espèce C. cephus et la sous-espèceC. c. cephus apparaissent significativement polyphylétique, ce qui pourrait être la conséquence dephénomènes d’hybridation et/ou d’un polymorphisme ancestral important associé à une différentiationincomplète des lignées. Ces résultats suggèrent que l’ADN mitochondrial est insuffisant pour distinguerles espèces et sous-espèces au sein des super-espèces de la tribu des Cercopithecini. La détermination del’origine géographique des spécimens pourrait cependant être envisagée, moyennant un échantillonnagepréalable des régions d’origine potentielle

Population structure and group composition of western lowland gorillas in north-western Republic of Congo

WOS:000080003100001International audiencePopulation studies are an essential part of conservation actions. Under exceptional observation conditions we studied a western lowland gorilla population visiting the Maya salt-clearing (north of the Pare national d'Odzala, P.N.O., Congo) over an 8 month period; 36 groups and 18 solitary individuals (a total of 420 individuals) have been identified visiting the clearing, which suggests a high gorilla density in the region. Ninety-six percent of the gorillas entered the clearing in groups. One-male groups had a mean size of 11.2. Ninety percent of solitary individuals were silver-back males. Compared with other populations of both lowland gorillas and mountain gorillas, the Maya population had the highest immature rate and the highest number of infants per female. Ecological correlates that could explain the attractiveness of the Maya clearing are discussed. The present status and the renewal rate of the Maya population indicate the need for further studies and confirm the importance of developing eco-tourism in this region as part of the sustainable park management activities developed by the ECOFAC programme (European Union). The results also provide arguments to support the proposal for extending the P.N.O. to include this region, which is rich in salt-clearings and attracts many other key-species of mammal such as forest elephants. Am. J. Primatol. 48:1-14, 1999. (C) 1999 Wiley-Liss, Inc

Grouping patterns, reproduction and dispersal in a population of sitatungas (Tragelaphus spekei gratus)

International audienceA population of sitatungas (Tragelaphus spekei gratus) living in a forest swamp clearing, Maya Nord, in the Republic of Congo was studied over 3½ years and its grouping patterns and population dynamics were analysed. The sitatungas in this clearing formed a stable group, which remained in residence. The group (16–36 individuals) functioned like a harem. As a result of intrasexual competition, all the males and some of the females born at Maya left the group before reaching sexual maturity. We hypothesize that this large grouping resulted from the development of a tendency for females to be gregarious for reasons related to food availability. This tendency, combined with an aseasonal pattern of reproduction, favours direct monopolization of females by one male. Social and mating strategies observed at Maya fit the model of “female-defence polygyny” (Emlen and Oring). Our results provide an argument in favour of relating food availability and grouping patterns, and underline the plasticity of social organization and mating strategies in sitatungas