Evidence for distinct coastal and offshore communities of bottlenose dolphins in the north east Atlantic.

Bottlenose dolphin stock structure in the northeast Atlantic remains poorly understood. However, fine scale photo-id data have shown that populations can comprise multiple overlapping social communities. These social communities form structural elements of bottlenose dolphin (Tursiops truncatus) [corrected] populations, reflecting specific ecological and behavioural adaptations to local habitats. We investigated the social structure of bottlenose dolphins in the waters of northwest Ireland and present evidence for distinct inshore and offshore social communities. Individuals of the inshore community had a coastal distribution restricted to waters within 3 km from shore. These animals exhibited a cohesive, fission-fusion social organisation, with repeated resightings within the research area, within a larger coastal home range. The offshore community comprised one or more distinct groups, found significantly further offshore (>4 km) than the inshore animals. In addition, dorsal fin scarring patterns differed significantly between inshore and offshore communities with individuals of the offshore community having more distinctly marked dorsal fins. Specifically, almost half of the individuals in the offshore community (48%) had characteristic stereotyped damage to the tip of the dorsal fin, rarely recorded in the inshore community (7%). We propose that this characteristic is likely due to interactions with pelagic fisheries. Social segregation and scarring differences found here indicate that the distinct communities are likely to be spatially and behaviourally segregated. Together with recent genetic evidence of distinct offshore and coastal population structures, this provides evidence for bottlenose dolphin inshore/offshore community differentiation in the northeast Atlantic. We recommend that social communities should be considered as fundamental units for the management and conservation of bottlenose dolphins and their habitat specialisations

Range Expansion Drives Dispersal Evolution In An Equatorial Three-Species Symbiosis

A-09-14International audienceBackground Recurrent climatic oscillations have produced dramatic changes in species distributions. This process has been proposed to be a major evolutionary force, shaping many life history traits of species, and to govern global patterns of biodiversity at different scales. During range expansions selection may favor the evolution of higher dispersal, and symbiotic interactions may be affected. It has been argued that a weakness of climate fluctuation-driven range dynamics at equatorial latitudes has facilitated the persistence there of more specialized species and interactions. However, how much the biology and ecology of species is changed by range dynamics has seldom been investigated, particularly in equatorial regions. Methodology/Principal Findings We studied a three-species symbiosis endemic to coastal equatorial rainforests in Cameroon, where the impact of range dynamics is supposed to be limited, comprised of two species-specific obligate mutualists –an ant-plant and its protective ant– and a species-specific ant parasite of this mutualism. We combined analyses of within-species genetic diversity and of phenotypic variation in a transect at the southern range limit of this ant-plant system. All three species present congruent genetic signatures of recent gradual southward expansion, a result compatible with available regional paleoclimatic data. As predicted, this expansion has been accompanied by the evolution of more dispersive traits in the two ant species. In contrast, we detected no evidence of change in lifetime reproductive strategy in the tree, nor in its investment in food resources provided to its symbiotic ants. Conclusions/Significance Despite the decreasing investment in protective workers and the increasing investment in dispersing females by both the mutualistic and the parasitic ant species, there was no evidence of destabilization of the symbiosis at the colonization front. To our knowledge, we provide here the first evidence at equatorial latitudes that biological traits associated with dispersal are affected by the range expansion dynamics of a set of interacting species

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

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 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 sitatungas 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 crottins 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.Magliocca Florence, Querouil Sophie, Gautier-Hion Annie. Seed eating in elephant dung by two large mammals in the Congo Republic. In: Revue d'Écologie (La Terre et La Vie), tome 58, n°1, 2003. pp. 143-149

Mitochondrial phylogeny of African wood mice, genus Hylomyscus (Rodentia, Muridae): Implications for their taxonomy and biogeography

This paper investigates the usefulness of two mitochondrial genes (16S rRNA and cytochrome b) to solve taxonomical difficulties within the genus Hylomyscus and to infer its evolutionary history. Both genes proved to be suitable molecular markers for diagnosis of Hylomyscus species. Nevertheless the resolving powers of these two genes diVer, and with both markers (either analyzed singly or in combination), some nodes remain unresolved. This is probably related to the fact that the species emerged during a rapid diversiWcation event that occurred 2–6Myr ago (4–5 Myr ago for most divergence events). Our molecular data support the recognition of an “aeta” group, while the “alleni” and “parvus” groups are not fully supported. Based on tree topology and genetic divergence, two taxa generally recognized as subspecies should be elevated at the species level (H. simus and H. cf kaimosae). H. stella populations exhibit ancient haplotype segregation that may represent currently unrecognized allopatric species. The existence of cryptic species within H. parvus is questioned. Finally, three potentially new species may occur in West Central Africa. The Congo and Oubangui Rivers, as well as the Volta and Niger Rivers and/or the Dahomey gap could have formed eVective barriers to Hylomyscus species dispersal, favoring their speciation in allopatry. The pronounced shifts in African climate during the late Pliocene and Miocene, which resulted in major changes in the distribution and composition of the vegetation, could have promoted speciation within the genus (refuge theory). Future reports should focus on the geographic distribution of Hylomyscus species in order to get a better understanding of the evolutionary history of the genus

Mitochondrial phylogeny of African wood mice, genus Hylomyscus (Rodentia, Muridae): Implications for their taxonomy and biogeography

This paper investigates the usefulness of two mitochondrial genes (16S rRNA and cytochrome b) to solve taxonomical difficulties within the genus Hylomyscus and to infer its evolutionary history. Both genes proved to be suitable molecular markers for diagnosis of Hylomyscus species. Nevertheless the resolving powers of these two genes diVer, and with both markers (either analyzed singly or in combination), some nodes remain unresolved. This is probably related to the fact that the species emerged during a rapid diversiWcation event that occurred 2–6Myr ago (4–5 Myr ago for most divergence events). Our molecular data support the recognition of an “aeta” group, while the “alleni” and “parvus” groups are not fully supported. Based on tree topology and genetic divergence, two taxa generally recognized as subspecies should be elevated at the species level (H. simus and H. cf kaimosae). H. stella populations exhibit ancient haplotype segregation that may represent currently unrecognized allopatric species. The existence of cryptic species within H. parvus is questioned. Finally, three potentially new species may occur in West Central Africa. The Congo and Oubangui Rivers, as well as the Volta and Niger Rivers and/or the Dahomey gap could have formed eVective barriers to Hylomyscus species dispersal, favoring their speciation in allopatry. The pronounced shifts in African climate during the late Pliocene and Miocene, which resulted in major changes in the distribution and composition of the vegetation, could have promoted speciation within the genus (refuge theory). Future reports should focus on the geographic distribution of Hylomyscus species in order to get a better understanding of the evolutionary history of the genus

DETERMINACIÓN DE PARENTESCO EN LARVAS DE Pseudoplatystoma fasciatum (Linnaeus, 1766) PRODUCIDAS EN CAUTIVERIO

Un set de seis loci microsatélites fue utilizado como herramienta molecular para identificar el genotipo de los reproductores y asignar el parentesco a diferentes familias de Pseudoplatystoma fasciatum. Las progenies cultivadas en situación comunal fueron obtenidas por la reproducción inducida de los óvulos de una hembra con un pool de esperma de cuatro machos. Todos los loci microsatélites mostraron apropiada amplificación y polimorfismo, con alelos diagnósticos o combinación de alelos para identificar a los reproductores y asignar el parentesco sin riesgo a equivocarse. Los alelos nulos encontrados en los loci Pcor 7 y Pcor 8, no dificultaron la identificación de la progenie. Se obtuvieron cuatro familias de medio-hermanos (en cada etapa de muestreo). Resultados de este estudio demuestran la utilidad de las herramientas genéticas en la asignación de parentesco en familias de Pseudoplatystoma fasciatum cultivadas comunalmente