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Université de Fribourg

The use of digital image-based morphometrics to study the phenotypic mosaic in taxa with porous genomes

Lexer, Christian ; Jeffrey, Joseph ; Loo, Marcela van ; Prenner, Gerhard ; Heinze, Berthold ; Chase, Mark W. ; Kirkup, Don

In: Taxon, 2009, vol. 58, no. 2, p. 349-364

Rapid recent developments in DNA sequencing and genetic marker technologies call for the establishment of cost-effective, automated phenotyping assays for evolutionary biology and systematics, so that the effects of DNA polymorphisms and epigenetic changes on the phenotype can be evaluated. We discuss the use of digital image-based morphometrics in evolutionary biology and systematics with...

Université de Fribourg

Fitness differences associated with Pgi SNP genotypes in the Glanville fritillary butterfly (Melitaea cinxia)

Orsini, L. ; Wheat, C. W. ; Haag, Christoph R. ; Kvist, J. ; Frilander, M. J. ; Hanski, I.

In: Journal of Evolutionary Biology, 2009, vol. 22, no. 2, p. 367-375

llozyme variation at the phosphoglucose isomerase (PGI) locus in the Glanville fritillary butterfly (Melitaea cinxia) is associated with variation in flight metabolic rate, dispersal rate, fecundity and local population growth rate. To map allozyme to DNA variation and to survey putative functional variation in genomic DNA, we cloned the coding sequence of Pgi and identified nonsynonymous...

Université de Fribourg

Impact of flower-dwelling crab spiders on plant-pollinator mutualisms

Brechbühl, Rolf ; Kropf, Christian ; Bacher, Sven

In: Basic and Applied Ecology, 2009///10.1016/j.baae.2009.07.001

Indirect effects in interactions occur when a species influences a third species by modifying the behaviour of a second one. It has been suggested that indirect effects of crab spiders (Thomisidae) on pollinator behaviour can cascade down the food web and negatively affect plant fitness. However, it is poorly understood how different pollinator groups react to crab spiders and, thus, when a...

Université de Fribourg

Ineffective crypsis in a crab spider: a prey community perspective

Brechbühl, Rolf ; Casas, Jérôme ; Bacher, Sven

In: Proceedings of the Royal Society B: Biological Sciences, 2009///doi: 10.1098/rspb.2009.1632

Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider...

Université de Fribourg

How well do we understand the impacts of alien species on ecosystem services? A pan-European, cross-taxa assessment

Vilà, Montserrat ; Basnou, Corina ; Pyšek, Petr ; Josefsson, Melanie ; Genovesi, Piero ; Gollasch, Stephan ; Nentwig, Wolfgang ; Olenin, Sergej ; Roques, Alain ; Roy, David ; Hulme, Philip E ; partners, DAISIE

In: Frontiers in Ecology and the Environment, 2009///doi: 10.1890/080083

Recent comprehensive data provided through the DAISIE project (www.europe-aliens.org) have facilitated the development of the first pan-European assessment of the impacts of alien plants, vertebrates, and invertebrates – in terrestrial, freshwater, and marine environments – on ecosystem services. There are 1094 species with documented ecological impacts and 1347 with economic impacts. The two...

Université de Fribourg

Determinants of local ant (Hymenoptera: Formicidae) species richness and activity density across Europe

Kumschick, Sabrina ; Schmidt-Entling, Martin H. ; Bacher, Sven ; Hickler, Thomas ; Espadaler, Xavier ; Nentwig, Wolfgang

In: Ecological Entomology, 2009, vol. 34, no. 6, p. 748 - 754

1. Species richness is influenced by local habitat features and large-scale climatic gradients. Usually, both influences are studied in isolation because of the divergent spatial scales at which they occur. Here, we compared the influence of large-scale climate and local habitat type on European ants using a continent-wide, standardised sampling programme.2. We investigated species richness and...

Université de Fribourg

Body size–climate relationships of European spiders

Entling, Wiebke ; Schmidt-Entling, Martin H. ; Bacher, Sven ; Brandl, Roland ; Nentwig, Wolfgang

In: Journal of Biogeography, 2009///doi: 10.1111/j.1365-2699.2009.02216.x

Aim: Geographic body size patterns of mammals and birds can be partly understood under the framework of Bergmann's rule. Climatic influences on body size of invertebrates, however, appear highly variable and lack a comparable, generally applicable theoretical framework. We derived predictions for body size–climate relationships for spiders from the literature and tested them using three...

Université de Fribourg

Alien species in a warmer world: risks and opportunities

Walther, Gian-Reto ; Roques, Alain ; Hulme, Philip E. ; Sykes, Martin T. ; Pyšek, Petr ; Kühn, Ingolf ; Zobel, Martin ; Bacher, Sven ; Botta-Dukát, Zoltán ; Bugmann, Harald ; Czúcz, Bálint ; Dauber, Jens ; Hickler, Thomas ; Jarošík, Vojtěch ; Kenis, Marc ; Klotz, Stefan ; Minchin, Dan ; Moora, Mari ; Nentwig, Wolfgang ; Ott, Jürgen ; Panov, Vadim E. ; Reineking, Björn ; Robinet, Christelle ; Semenchenko, Vitaliy ; Solarz, Wojciech ; Thuiller, Wilfried ; Vilà, Montserrat ; Vohland, Katrin ; Settele, Josef

In: Trends in Ecology & Evolution, 2009, vol. 24, no. 12, p. 686-693

Climate change and biological invasions are key processes affecting global biodiversity, yet their effects have usually been considered separately. Here, we emphasise that global warming has enabled alien species to expand into regions in which they previously could not survive and reproduce. Based on a review of climate-mediated biological invasions of plants, invertebrates, fishes and birds, we...

Université de Fribourg

Status of the endangered ivory gull, Pagophila eburnea, in Greenland

Gilg, Olivier ; Boertmann, David ; Merkel, Flemming ; Aebischer, Adrian ; Sabard, Brigitte

In: Polar Biology, 2009, vol. 32, no. 9, p. 1275-1286

The ivory gull, a rare high-Arctic species whose main habitat throughout the year is sea ice, is currently listed in Greenland as ‘Vulnerable’, and as ‘Endangered’ in Canada, where the population declined by 80% in 20 years. Despite this great concern, the status of the species in Greenland has been largely unknown as it breeds in remote areas and in colonies for which population data has...

Université de Fribourg

Information filtering based on transferring similarity

Sun, Duo ; Zhou, Tao ; Liu, Jian-Guo ; Liu, Run-Ran ; Jia, Chun-Xiao ; Wang, Bing-Hong

In: Physical Review E, 2009, vol. 80, no. 1, p. 017101

n this Brief Report, we propose an index of user similarity, namely, the transferring similarity, which involves all high-order similarities between users. Accordingly, we design a modified collaborative filtering algorithm, which provides remarkably higher accurate predictions than the standard collaborative filtering. More interestingly, we find that the algorithmic performance will approach...