Université de Fribourg

Parasite‐driven replacement of a sexual by a closely related asexual taxon in nature

Lohr, Jennifer N. ; Haag, Christoph R.

In: Ecology, 2020, vol. 101, no. 10, p. -

Asexual species are thought to suffer more from coevolving parasites than related sexuals. Yet a variety of studies do not find the patterns predicted by theory. Here, to shine light on this conundrum, we investigate one such case of an asexual advantage in the presence of parasites. We follow the frequency dynamics of sexual and asexual Daphnia pulex in a natural pond that was initially...

Université de Fribourg

Reduced lifespan and increased ageing driven by genetic drift in small populations

Lohr, Jennifer N. ; David, Patrice ; Haag, Christoph R.

In: Evolution, 2014, vol. 68, no. 9, p. 2494–2508

Explaining the strong variation in lifespan among organisms remains a major challenge in evolutionary biology. Whereas previous work has concentrated mainly on differences in selection regimes and selection pressures, we hypothesize that differences in genetic drift may explain some of this variation. We develop a model to formalize this idea and show that the strong positive relationship between...

Université de Fribourg

A daphnia parasite (Caullerya mesnili) constitutes a new member of the ichthyosporea, a group of protists near the animal - fungi divergence

Lohr, Jennifer N. ; Laforsch, Christian ; Koerner, Henrike ; Wolinska, Justyna

In: Journal of Eukaryotic Microbiology, 2010, vol. 57, no. 4, p. 328–336

Caullerya mesnili is a protozoan endoparasite in the gut epithelium of Daphnia, which causes regular epidemics in lakes throughout Europe. Its classification has remained unchanged for over a century, leaving it placed with the Haplosporidia, despite speculation that this position is incorrect. The difficulty in classifying C. mesnili stems from its few known morphological and ecological...

Université de Fribourg

Prior residency does not always pay off – co-infections in Daphnia

Lohr, Jennifer N. ; Yin, Mingbo ; Wolinska, Justyna

In: Parasitology, 2010, p. -

The epidemiological and ecological processes which govern the success of multiple-species co-infections are as yet unresolved. Here we investigated prior versus late residency within hosts, meaning which parasite contacts the host first, to determine if the outcomes of intra-host competition are altered. We infected a single genotype of the waterflea Daphnia galeata with both the...