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Article Reference A gigantic bird from the Upper Cretaceous of Central Asia
Located in Library / RBINS Staff Publications
Article Reference Repeated unidirectional introgression of nuclear and mitochondrial DNA between four congeneric Tanganyikan cichlids.
With an increasing number of reported cases of hybridization and introgression, interspecific gene flow between animals has recently become a widely accepted and broadly studied phenomenon. In this study, we examine patterns of hybridization and introgression in Ophthalmotilapia spp., a genus of cichlid fish from Lake Tanganyika, using mitochondrial and nuclear DNA from all four species in the genus and including specimens from over 800 km of shoreline. These four species have very different, partially overlapping distribution ranges, thus allowing us to study in detail patterns of gene flow between sympatric and allopatric populations of the different species. We show that a significant proportion of individuals of the lake-wide distributed O. nasuta carry mitochondrial and/or nuclear DNA typical of other Ophthalmotilapia species. Strikingly, all such individuals were found in populations living in sympatry with each of the other Ophthalmotilapia species, strongly suggesting that this pattern originated by repeated and independent episodes of genetic exchange in different parts of the lake, with unidirectional introgression occurring into O. nasuta. Our analysis rejects the hypotheses that unidirectional introgression is caused by natural selection favoring heterospecific DNA, by skewed abundances of Ophthalmotilapia species or by hybridization events occurring during a putative spatial expansion in O. nasuta. Instead, cytonuclear incompatibilities or asymmetric behavioral reproductive isolation seem to have driven repeated, unidirectional introgression of nuclear and mitochondrial DNA into O. nasuta in different parts of the lake.
Located in Library / RBINS Staff Publications
Article Reference Rapidly evolving lineages impede the resolution of phylogenetic relationships among Clitellata (Annelida).
The phylogenetic relationships of the Clitellata were investigated using a data set with published and new complete or partial 18S rRNA and mtCOI gene sequences of 13 and 49 taxa representing 8 and 14 families, respectively. Three different alignments were considered for 18S, and the possible influence of departures from rate constancy among sites was evaluated by analyses using a Gamma model of rate heterogeneity. Maximum-likelihood estimates of the shape parameter alpha of the Gamma distribution were very low, whatever the alignment or the gene considered, suggesting that phylogenetic reconstructions taking into account the rate heterogeneity among sites are likely to be the most reliable. Analyzed separately, the two genes did not resolve the relationships among the Clitellata, but the consensus tree was congruent with the morphology-based relationships. Our data suggest the inclusion of the Euhirudinea, Acanthobdellida, and Branchiobdellida in the Oligochaeta and suggest the Lumbriculidae as the link between both assemblages. Although separate analyses of both genes, as well as different alignments for the 18S rRNA sequences, yielded conflicting results concerning the phylogenetic position of leeches and leech-like worms vis-à-vis the Oligochaeta, subsequent analyses using the Gamma model greatly reduced the observed inconsistencies. Our analyses show that among the Clitellata, the leeches and the leech-like and gutless worms represent significantly faster evolving lineages. It is suggested that the observed higher mutation rates may be explained by the fact that these lineages contain almost exclusively commensal and/or parasitic taxa.
Located in Library / RBINS Staff Publications
Article Reference A mitochondrial phylogeographic scenario for the most widespread African rodent species , Mastomys natalensis
In order to evaluate the contribution of geological, environmental, and climatic changes to the spatial distri- bution of genetic variation of Mastomys natalensis, we analysed cytochrome b sequences from the whole dis- tribution area of the species to infer its phylogeographic structure and historical demography. Six well-supported phylogroups, differentiated during the Pleistocene, were evidenced. No significant correlation between genetic and geographic distances was found at the continental scale, and the geographic distributions of the observed phylogroups have resulted from extensive periods of isolation caused by the presence of putative geographic and ecological barriers. The diversification events were probably influenced by habitat contraction/expansion cycles that may have complemented topographic barriers to induce genetic drift and lineage sorting. According to our results, we propose a scenario where climate-driven processes may have played a primary role in the differ- entiation among phylogroups.
Located in Library / RBINS Staff Publications
Article Reference Establishment of ant communities in forests growing on former agricultural fields: Colonisation and 25 years of management are not enough (Hymenoptera: Formicidae)
Located in Library / RBINS Staff Publications
Article Reference Changes in the distribution of carabid beetles in Belgium revisited: Have we halted the diversity loss?
Located in Library / RBINS Staff Publications
Article Reference Ant biodiversity conservation in Belgian calcareous grasslands: active management is vital
Located in Library / RBINS Staff Publications
Article Reference Acceptance of two native myrmecophilous species, Platyarthrus hoffmannseggii (Isopoda : Oniscidea) and Cyphoderus albinus (Collembola : Cyphoderidae) by the introduced invasive garden ant Lasius neglectus (Hymenoptera : Formicidae) in Belgium
Located in Library / RBINS Staff Publications
Article Reference Loss of genetic diversity and increased genetic structuring in response to forest area reduction in a ground dwelling insect: a case study of the flightless carabid beetle Carabus problematicus (Coleoptera: Carabidae)
Located in Library / RBINS Staff Publications
Article Reference Local extinction processes rather than edge effects affect ground beetle assemblages from fragmented and urbanized old beech forests
Local extinction of specialist species due to fragmentation is one of the major causes of biodiversity loss. Increased extinction rates in smaller fragments are expected to result from both smaller local population sizes, which increase the effect of environmental or demographic stochasticity, and increased edge effects. However, the relative effect sizes of these two factors are still poorly investigated. We attempt to disentangle these effects on ground beetle communities of temperate broadleaved woodland fragments situated in one of the most urbanized regions in Belgium. Assemblages were sampled along transects that extended from 30 m outside to 100 m inside both small and large historic forest fragments. Although species assemblages within the forest were highly distinct compared to those sampled outside the forest, species turnover along these transects was less pronounced within forest fragments indicating only weak edge effects. The magnitude of edge effects did not differ significantly between large and small fragments. However, larger differences in species composition were observed with respect to fragment size, wherein highly specialized species persisted only in the largest fragment. In sum, increased local extinction processes in smaller fragments, which led to a strong reduction of specialized and wingless forest species, appeared to be the most important factor that drives changes in species composition in this historic and fragmented woodland complex.
Located in Library / RBINS Staff Publications