| 1. |
- Bergsten, Johannes, et al.
(författare)
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The Effect of Geographical Scale of Sampling on DNA Barcoding
- 2012
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Ingår i: Systematic Biology. - : Oxford University Press (OUP). - 1063-5157 .- 1076-836X. ; 61:5, s. 851-869
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Tidskriftsartikel (refereegranskat)abstract
- Eight years after DNA barcoding was formally proposed on a large scale, CO1 sequences are rapidly accumulating from around the world. While studies to date have mostly targeted local or regional species assemblages, the recent launch of the global iBOL project (International Barcode of Life), highlights the need to understand the effects of geographical scale on Barcoding's goals. Sampling has been central in the debate on DNA Barcoding, but the effect of the geographical scale of sampling has not yet been thoroughly and explicitly tested with empirical data. Here, we present a CO1 data set of aquatic predaceous diving beetles of the tribe Agabini, sampled throughout Europe, and use it to investigate how the geographic scale of sampling affects 1) the estimated intraspecific variation of species, 2) the genetic distance to the most closely related heterospecific, 3) the ratio of intraspecific and interspecific variation, 4) the frequency of taxonomically recognized species found to be monophyletic, and 5) query identification performance based on 6 different species assignment methods. Intraspecific variation was significantly correlated with the geographical scale of sampling (R-square = 0.7), and more than half of the species with 10 or more sampled individuals (N = 29) showed higher intraspecific variation than 1%, sequence divergence. In contrast, the distance to the closest heterospecific showed a significant decrease with increasing geographical scale of sampling. The average genetic distance dropped from >7% for samples within 1 km, to <3.5% for samples up to >6000 km apart. Over a third of the species were not monophyletic, and the proportion increased through locally, nationally, regionally, and continentally restricted subsets of the data. The success of identifying queries decreased with increasing spatial scale of sampling; liberal methods declined from 100% to around 90%, whereas strict methods dropped to below 50% at continental scales. The proportion of query, identifications considered uncertain (more than one species <1% distance from query) escalated from zero at local, to 50% at continental scale. Finally, by resampling the most widely sampled species we show that even if samples are collected to maximize the geographical coverage, up to 70 individuals are required to sample 95%, of intraspecific variation. The results show that the geographical scale of sampling has a critical impact on the global application of DNA barcoding. Scale-effects result from the relative importance of different processes determining the composition of regional species assemblages (dispersal and ecological assembly) and global clades (demography, speciation, and extinction). The incorporation of geographical information, where available, will be required to obtain identification rates at global scales equivalent to those in regional barcoding studies. Our result hence provides an impetus for both smarter barcoding tools and sprouting national barcoding initiatives smaller geographical scales deliver higher accuracy.
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| 2. |
- Balke, Michael, et al.
(författare)
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A new genus and two new species of Southeast Asian Bidessini as well as new synonyms for Oceanian species (Coleoptera, Dytiscidae)
- 2017
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Ingår i: ZooKeys. - : Pensoft Publishers. - 1313-2989 .- 1313-2970. ; 647, s. 137-151
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Tidskriftsartikel (refereegranskat)abstract
- Rompindessus jenisi Balke, Bergsten & Hendrich, gen. n. et sp. n. is described from near Rompin village in West Malaysia. The new genus is characterized by the presence of an occipital line and basal pronotal striae, the presence of a thick anterior bead on clypeus and two-segmented parameres as well as by the absence of basal elytral striae, the absence of sutural line on elytron, the absence of basal epipleural transverse carina, and the absence of longitudinal elytral carina. Moreover, male pro- and mesotarsus appear stout, and distinctly dilated laterally; the pronotum is comparably long and parallel-sided and the colour of beetle conspicuous dark orange. Leiodytes kualalipis Balke, Wang, Bergsten & Hendrich, sp. n. is described from West Malaysia (Pahang) and South Vietnam (Cat Tien). It is well characterized by its large size, elongate body and the form of the median lobe. Limbodessus fijiensis (J. Balfour-Browne, 1944), comb. n. described from Fiji is a new synonym of Limbodessus curviplicatus (Zimmermann, 1927) described from Samoa.
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| 3. |
- Espeland, Marianne, 1981-
(författare)
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Diversification on an ancient Darwinian island : Evolutionary history of caddisflies (Trichoptera) and other organisms on New Caledonia
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Islands are either of continental or oceanic origin, and the biota of such islands are a result of vicariance and dispersal, respectively. New Caledonia, in the South Pacific, is a part of former Gondwana, but the origin of its biota is heavily debated. Geological studies show that the island was submerged in the Eocene, and that oceanic crust was obducted onto New Caledonia leaving a thick layer of ultramafic rocks on top of the island. We tested the null hypothesis that New Caledonian biota are a result of old Gondwanan vicariance by fitting diversification models on phylogenies from the literature and calculating the gamma statistic. According to the null hypothesis diversification is gradual over time. If on the other hand the biota are a result of recent dispersal or have survived in refugia we would expect slowing of diversification over time. Based on our results we can reject the null hypothesis of old vicariance for the New Caledonian biota. The caddisfly (Trichoptera) fauna on New Caledonia is exceptionally rich with around 600 species, and more than 99.9% are endemic. Molecular phylogenetic hypotheses for three monophyletic caddisfly radiations, Xanthochorema, Caledopsyche et al. and Agmina, are presented. Age estimates agrees with the geological evidence. Three new species of Xanthochorema are described and more than 63% of the Agmina species are new to science. The ultramafic rock substrate, with high heavy metal concentration, has led to high levels of plant adaptation on New Caledonia. We show that caddisflies adapted early to this substrate and subsequently dispersed to non-ultramafic substrate several times, with significantly fewer dispersal events back to the toxic substrate, indicating that adaptation to ultramafic substrate is required and recolonization is difficult when this adaptation has been lost. Ultramafic substrate and other environmental factors have been important in driving the diversification of New Caledonian caddisflies.
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| 4. |
- Morinière, Jérôme, et al.
(författare)
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Anisomeriini diving beetles – an Atlantic-Pacific Island disjunction on Tristan da Cunha and Robinson Crusoe Island, Juan Fernández?
- 2015
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Ingår i: Cladistics. - : Wiley. - 0748-3007 .- 1096-0031.
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Tidskriftsartikel (refereegranskat)abstract
- Anisomeriini diving beetles contain only two enigmatic species, representing a remarkable disjunction between the Pacific Juan Fernández Islands (Anisomeria bistriata) and the South Atlantic Tristan da Cunha Archipelago (Senilites tristanicola). They belong to the Colymbetinae, which contain 140 species worldwide. Here we aim to reconstruct the evolutionary history of the Anisomerinii and use > 9000 bp DNA sequence data from 13 fragments of 12 loci for a comprehensive sampling of Colymbetinae species. Analyses under different optimization criteria converge on very similar topologies, and show unambiguously that Anisomeria bistriata andSenilites tristanicola belong to the Neotropical Rhantus signatus species group, a comparatively recent clade within Colymbetinae. Anisomeriini therefore are synonomized with Colymbetini and both species are transferred to Rhantus accordingly, resulting in secondary homonymy of Rhantus bistriatus (Brullé, 1835) with Rhantus bistriatus (Bergsträsser, 1778). We propose the replacement name Rhantus selkirki Jäch, Balke & Michat nom. nov. for the Juan Fernández species. Presence of these species on remote islands is therefore not relictary, but the result of more recent range expansions out of mainland South America. Finally, we suggest that Carabdytini should be synonymized with Colymbetini. Our study underpins the Hennigian principle that a natural classification can be derived only from the search for shared apomorphies between species, not from differences.
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| 5. |
- Morinière, Jérôme, et al.
(författare)
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Phylogenetic niche conservatism explains an inverse latitudinal diversity gradient in freshwater arthropods.
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The underlying mechanisms responsible for the general increase in species richness from temperate regions to the tropics remain equivocal. Many hypotheses have been proposed to explain this astonishing pattern but additional empirical studies are needed to shed light on the drivers at work. Here we reconstruct the evolutionary history of the cosmopolitan diving beetle subfamily Colymbetinae, the majority of which are found in the Northern hemisphere, hence exhibiting an inversed latitudinal diversity gradient. We reconstructed a dated phylogeny using 12 genes, to investigate the biogeographical history and diversification dynamics in the Colymbetinae. We aimed to identify the role that phylogenetic niche conservatism plays in the inversed diversification pattern seen in this group. Our results suggest that Colymbetinae originated in temperate climates, which supports the hypothesis that their distribution is the result of an ancestral adaptation to temperate environmental conditions rather than tropical origins, and that temperate niche conservatism can generate and/or maintain inverse latitudinal diversity gradients.
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| 6. |
- Singh, Munindar P., et al.
(författare)
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The Uses of Norms
- 2013
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Ingår i: Normative Multi-Agent Systems. - Dagstuhl : Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik. - 9783939897514 ; , s. 191-229
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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