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Université de Fribourg

Learning ability and longevity: a symmetrical evolutionary trade-off in Drosophila

Burger, Joep M. S. ; Kolss, Munjong ; Pont, Juliette ; Kawecki, Tadeusz J.

In: Evolution, 2008, vol. 62, no. 6, p. 1294–1304

Learning ability can be substantially improved by artificial selection in animals ranging from Drosophila to rats. Thus these species have not used their evolutionary potential with respect to learning ability, despite intuitively expected and experimentally demonstrated adaptive advantages of learning. This suggests that learning is costly, but this notion has rarely been tested. Here we report...

Université de Fribourg

Evidence for epistasis: reply to Trouve et al.

Ebert, Dieter ; Salathé, P. ; Kawecki, Tadeusz J.

In: Journal of Evolutionary Biology, 2004, vol. 17, p. 1402-1404

Salathé and Ebert (2003, J. Evol. Biol. 16: 976-985) have shown that the mean logarithmic fitness of Daphnia magna clones declined faster than linearly with increasing inbreeding coefficient F. They interpreted this result as evidence for synergistic epistasis. Trouve et al. (2004, J. Evol. Biol., doi: 10.1111/j.1420-9101.2004.00755.x) suggested that hybrid vigour could be an alternative...

Université de Fribourg

Juvenile hormone as a regulator of the trade-off between reproduction and life span in Drosophila melanogaster

Flatt, Thomas ; Kawecki, Tadeusz J.

In: Evolution, 2007, vol. 61, no. 8, p. 1980–1991

Trade-offs between reproduction and life span are ubiquitous, but little is known about their underlying mechanisms. Here we combine treatment with the juvenile hormone analog (JHa) methoprene and experimental evolution in Drosophila melanogaster to study the potential role of juvenile hormone (JH) in mediating such trade-offs at both the physiological and evolutionary level. Exposure to...

Université de Fribourg

SV40-induced expression of calretinin protects mesothelial cells from asbestos cytotoxicity and may be a key factor contributing to mesothelioma pathogenesis

Henzi, Thomas ; Blum, Walter-Vincent ; Pfefferli, Martine ; Kawecki, Tadeusz J. ; Salicio, Valérie ; Schwaller, Beat

In: American Journal of Pathology, 2009, vol. 174, p. 2324-2336

The calcium-binding protein calretinin has emerged as a useful marker for the identification of mesotheliomas of the epithelioid and mixed types, but its putative role in tumor development has not been addressed previously. Although exposure to asbestos fibers is considered the main cause of mesothelioma, undoubtedly, not all mesothelioma patients have a history of asbestos exposure. The question...

Université de Fribourg

Conceptual issues in local adaptation

Kawecki, Tadeusz J. ; Ebert, Dieter

In: Ecology Letters, 2004, vol. 7, p. 1225-1241

Studies of local adaptation provide important insights into the power of natural selection relative to gene flow and other evolutionary forces. They are a paradigm for testing evolutionary hypotheses about traits favoured by particular environmental factors. This paper is an attempt to summarize the conceptual framework for local adaptation studies. We first review theoretical work relevant for...

Université de Fribourg

The effect of learning on experimental evolution of resource preference in Drosophila melanogaster

Kawecki, Tadeusz J. ; Mery, Frederic

In: Evolution, 2004, vol. 58, no. 4, p. 757-767

Learning is thought to be adaptive in variable environments, whereas constant, predictable environments are supposed to favor unconditional, genetically fixed responses. A dichotomous view of behavior as either learned or innate ignores a potential evolutionary interaction between the learned and innate components of a behavioral response. We addressed this interaction in the context of...

Université de Fribourg

Genetically idiosyncratic responses of Drosophila melanogaster populations to selection for improved learning ability

Kawecki, Tadeusz J. ; Mery, Frederic

In: Journal of Evolutionary Biology, 2006, vol. 19, no. 4, p. 1265-1274

To what extent is adaptive evolution over short timescales repeatable? To address this question, we studied the performance of crosses between replicate Drosophila melanogaster lines previously subject to selection for improved learning response in the context of oviposition substrate choice. Of the 10 pairwise F1 crosses among the five selection lines, four performed in the original learning...

Université de Fribourg

No trade-off between learning ability and parasitoid resistance in Drosophila melanogaster

Kolss, Munjong ; Kraaijeveld, A. R. ; Mery, Frederic ; Kawecki, Tadeusz J.

In: Journal of Evolutionary Biology, 2006, vol. 19, no. 4, p. 1359-1363

Learning ability and immunity to parasites are linked at the physiological level in several insect species. The aim of this work was to investigate the relationship between learning and immunity at an evolutionary level. We tested whether selection for improved learning ability in Drosophila melanogaster led to changes in parasitoid resistance as a correlated response. Similarly, we assayed...

Université de Fribourg

Reduced learning ability as a consequence of evolutionary adaptation to nutritional stress in Drosophila melanogaster

Kolss, Munjong ; Kawecki, Tadeusz J.

In: Ecological Entomology, 2008///doi:10.1111/j.1365-2311.2008.01007.x

Abstract. 1. Dietary conditions affect cognitive abilities of many species, but it is unclear to what extent this physiological effect translates into an evolutionary relationship.2. A reduction of competitive ability under nutritional stress has been reported as a correlated response to selection for learning ability in Drosophila melanogaster. Here we test whether the reverse holds as well,...

Université de Fribourg

Life history consequences of adaptation to larval nutritional stress in Drosophila

Kolss, Munjong ; Vijendravarma, Roshan K. ; Schwaller, Geraldine ; Kawecki, Tadeusz J.

In: Evolution, 2009///doi: 10.1111/j.1558-5646.2009.00718.x

Many animal species face periods of chronic nutritional stress where the individuals must continue to develop, grow and/or reproduce despite low quantity or quality of food. Here we use experimental evolution to study adaptation to such chronic nutritional stress in six replicate Drosophila melanogaster populations selected for the ability to survive and develop within a limited time on a very...