Benjamin Lejeune

PhD Student (FRIA grant holder)

Laboratory of Fish and Amphibian Ethology
Freshwater and OCeanic science Unit of reSearch (U.R. FOCUS)
University of Liege, Quai van Beneden 22, 4020 Liege, Belgium

Description of the doctoral research

I am interested in the study of facultative paedomorphosis in European newts’ populations of the species Ichthyosaura alpestris and Lissotriton helveticus and invasive species currently threatening these populations. Facultative paedomorphosis is a case of extreme phenotypic plasticity allowing for the retention of larval traits at the adult stage in some individuals of a population. In these rare populations, fully metamorphosed individuals (metamorphs) and individuals that retained larval gills (paedomorphs) share a common aquatic habitat during the reproductive period.

The aim of my PhD project is to understand the long-term maintenance of facultative paedomorphosis in two contrasting habitats (alpine lakes and ponds) by studying the trophic ecology of paedomorphic and metamorphic newts during their shared aquatic phase. Because facultative paedomorphosis is currently threatened by fish introductions in Europe, we are also studying the impact of introduced species of fish on these particular populations and their native trophic web.

Main study species: Ichthyosaura alpestris and Lissotriton helveticus.

Specific methodologies: In situ sampling (phytoplankton, zooplankton, macrophytes, aquatic macroinvertebrates, fish and amphibian tissues), stable isotope and stomach content analysis, niche modelling and analysis of ecological communities.

Promotor: Mathieu DenoëlCo-promotor: Gilles Lepoint

Publications and communications