Interactions between a large community of vertebrate frugivore-granivores (including 7 species of large canopy birds, 19 species of rodents, 7 species of ruminants, and 6 species of monkeys), and 122 fruit species they consume, were studied for a year in a tropical rainforest in Gabon.The results show how morphological characters of fruits are involved in the choice and partitioning of the available fruit spectrum among consumer taxa. Despite an outstanding lack of specificity between fruit and consumer species, consideration of simple morphological traits of fruits reveals broad character syndromes associated with different consumer taxa. Competition between distantly related taxa that feed at the same height is far more important than has been previously supposed. The results also suggest how fruit characters could have evolved under consumer pressure as a result of consumer roles as dispersers or seed predators. Our analyses of dispersal syndromes show that fruit species partitioning occurs more between mammal taxa than between mammals and birds. There is thus a bird-monkey syndrome and a ruminant-rodent-elephant syndrome. The bird-monkey syndrome includes fruit species on which there is no pre-dispersal seed predation. These fruits (berries and drupes) are brightly colored, have a succulent pulp or arillate seeds, and no protective seed cover. The ruminant-rodent-elephant syndrome includes species for which there is pre-dispersal predation. These fruits (all drupes) are large, dull-colored, and have a dry fibrous flesh and well-protected seeds.

Although parasite-host co-speciation is a long-held hypothesis, convincing evidence for long-term co-speciation remains elusive, largely because of small numbers of hosts and parasites studied and uncertainty over rates of evolutionary change. Co-speciation is especially rare in RNA viruses, in which cross-species transfer is the dominant mode of evolution. Simian foamy viruses (SFVs) are ubiquitous, non-pathogenic retroviruses that infect all primates. Here we test the co-speciation hypothesis in SFVs and their primate hosts by comparing the phylogenies of SFV polymerase and mitochondrial cytochrome oxidase subunit II from African and Asian monkeys and apes. The phylogenetic trees were remarkably congruent in both branching order and divergence times, strongly supporting co-speciation. Molecular clock calibrations revealed an extremely low rate of SFV evolution, 1.7 x 10(-8) substitutions per site per year, making it the slowest-evolving RNA virus documented so far. These results indicate that SFVs might have co-speciated with Old World primates for at least 30 million years, making them the oldest known vertebrate RNA viruses.

WOS:000239127800009International audience[No abstract

During a 17-month study at the Lokoué clearing in Odzala National Park, Republic of Congo, we identified 377 western lowland gorillas. This population included 31 solitary males, 37 breeding groups, and eight nonbreeding groups. Its age- and sex-class structure was similar to those observed at two other clearings in the same forest block. However, the size of breeding groups varied with site (either clearing or forest sites). At Lokoué, breeding groups (mean size: 8.2 gorillas; range: 3-15) included a single silverback male and, on average, 3.2 adult females. Nonbreeding groups (mean size: 5.5; range: 2-15) were devoid of adult females. Five of the nonbreeding groups were composed predominantly of blackbacks, subadult males, and juveniles, and thus fit the definition of all-male groups previously observed in mountain gorillas. Our study confirms that 1) one-male breeding groups are the norm in western gorillas, and 2) all-male groups occur in this species. Despite frequent changes in members due to migrations of the males, the persistence of these all-male groups indicates that they may play an important role in the life of migrating males. Variations in population structure, and group composition and type among gorilla populations are discussed. However, a further understanding of the evolution of group-living in gorillas requires detailed ecological studies conducted in parallel with studies of the population structure and dynamics of these groups.

International audience(1) Fruit, leaves and animal matter form the main part of the diets of the three Cercopithecus monkeys studied. Cercopithecus nictitans eats less fruit and insects and more leaves; C. pogonias more fruit and insects and fewer leaves; C. cephus is intermediate. (2) Sex-related differences occur: males eat more fruit than females who eat more leaves and animal matter, especially when these foods are abundant. (3) Interspecific differences in food items taken are small for fruit (68% of the species are taken by the three monkeys), obvious for animal matter. Cercopithecus nictitans preys mainly on sedentary prey (caterpillars, ants), C. pogonias on mobile ones (orthoptera) while C. cephus captures both types. Sex-related differences occur in C. cephus and C. pogonias. (4) Interspecific overlap in diets is great during the main part of the year. Species diets change and overlap less when fruit, young leaves and animal matter production are short (main dry season). This suggests that interspecific competition is important in determining resource partitioning. A second decrease in diet overlap occurs at the end of the long rainy season while foods are abundant. Females are either pregnant or lactating and select protein-richer foods such as young leaves and/or insects while males eat more fruit. At this time, intraspecific competition could be the selective force in food sharing. However increasing protein-requirements could account for the reorientation in food choice of the females. (5) The intermediate trophic position of C. cephus rests upon sex-related differences. The cephus male behaves like nictitans while the cephus female behaves like pogonias. (6) Interspecific differences are related to search strategies which depend on body weight, forest levels used, social roles, etc. Differences in spatial and temporal feeding patterns are small

International audiencePleistocene refuge theory has been strengthened in the Neotropics by much prominent and recent work. In contrast, models developed in the 1960s for Central African tropics are still retained to-day. Because these were based on knowledge of highland palaeoenvironments and biogeography, and on an almost blank page for lowland forests of the Central Zaire Basin, the discrimination between lowland and montane faunas remained imprecise, and their relative histories somewhat confused. Results of a 5-year study on primate distribution and systematics in the Zaire Basin do not support the previously proposed diversity gradients, and show that the so-called East Central major refuge was drawn from the addition of allopatric faunas. We point out the high specific richness and endemism of lowland forests on both sides of the Zaire River, and suggest the existence of a quaternary Major Fluvial Refuge. The validity of the palaeoenvironmental history currently proposed for Central Africa, especially the extent of lowering of montane forest and the degree of persistence of lowland forest, is questioned

Simian foamy viruses (SFVs) belong to a genetically and antigenically diverse class of retroviruses that naturally infect a wide range of nonhuman primates (NHPs) and can also be transmitted to humans occupationally exposed to NHPs. Current serologic detection of SFV infection requires separate Western blot (WB) testing by using two different SFV antigens [SFV(AGM) (African green monkey) and SFV(CPZ) (chimpanzee)]. However, this method is labor intensive and validation is limited to only small numbers of NHPs. To facilitate serologic SFV testing, we developed a WB assay that combines antigens from both SFV(AGM) and SFV(CPZ). The combined-antigen WB (CA-WB) assay was validated with 145 serum samples from 129 NHPs (32 African and Asian species) and 16 humans, all with known SFV infection status determined by PCR. Concordant CA-WB results were obtained for all 145 PCR-positive or -negative primate and human specimens, giving the assay a 100% sensitivity and specificity. In addition, no reactivity was observed in sera from persons positive for human immunodeficiency virus or human T cell lymphotropic virus (HIV/HTLV) (n = 25) or HIV/HTLV-negative U.S. blood donors (n = 100). Using the CA-WB assay, we screened 360 sera from 43 Old World primate species and found an SFV prevalence of about 68% in both African and Asian primates. We also isolated SFV from the blood of four seropositive primates (Allenopithecus nigroviridis, Trachypithecus françoisi, Hylobates pileatus, and H. leucogenys) not previously known to be infected with SFV. Phylogenetic analysis of integrase sequences from these isolates confirmed that all four SFVs represent new, distinct, and highly divergent lineages. These results demonstrate the ability of the CA-WB assay to detect infection in a large number of NHP species, including previously uncharacterized infections with divergent SFVs.

No abstract