PhD Offer
How can pesticides affect health status of birds on a gradient of organic farming?
The use of pesticides in agriculture, although recognised for having greatly improved
agricultural yields in recent decades, is responsible for sublethal effects in exposed organisms,
leading to adverse consequences for the populations concerned, particularly birds. Birds living
in areas exposed to pesticides are directly and indirectly affected by their use. Pesticides are
responsible for a decrease in the quantity and quality of food resources exploited by birds, and
alter essential physiological processes, such as the nervous, endocrine and reproductive
systems. However, the physiological mechanisms underlying these sublethal effects are still
poorly understood, particularly because the cocktail effect to which organisms are exposed in
nature must be considered, with long-term effects due to chronic exposure to low doses of
pesticides.
With this PhD project, we propose to measure the effects of pesticide exposure, on a gradient
of organic farming, on cellular energy metabolism and gut microbiota.
On one hand, mitochondrial metabolism is essential, as 90% of the energy required by
individuals throughout their lives comes mainly from mitochondria. However, the mitochondrial
function is deeply affected by the environmental conditions experienced by the organisms. We
can thus expect that an exposure to pesticides might affect the mitochondrial efficiency of
producing energy, as well as the production of reactive oxygen species (ROS), responsible for
an oxidative stress if they are present in a too high quantity in the organism.
On the other hand, the gut microbiota, through its predominant role in regulating individual
fitness and its essential functions related to nutrition, is an essential factor to consider.
Moreover, there appears to be a close relationship between mitochondrial metabolism and gut
microbiota, since an increased ROS production by mitochondria can affect the host’s gut
microbiota. In turn, the microbiota can produce molecules, such as short-chain fatty acids, that
regulate gene expression, which can alter mitochondrial function and biogenesis. Thus, a
better understanding of mitochondrial metabolism and the gut microbiota would make it
possible to (1) establish a complete bioenergetic profile of birds exposed to pesticides, and
therefore (2) better understand the long-term consequences at different biological levels of
chronic exposure to these molecules, which are now present in a large number of ecosystems.
For this project, we are looking for a candidate who:
– Has obtained a Master’s degree or equivalent in physiology, ecology, ecophysiology
or ecotoxicology.
– Is comfortable with laboratory and field experiments.
– Speaks English and/or French.
– Possesses skills in statistical analysis, knows how to use R or R Studio (or
equivalent).
Important information: The project is not currently funded, but a call for a grant to which
we will apply requires the identification of a candidate for the PhD.
PhD location: Nouvelle Aquitaine, France, between laboratories of LIENSs (La Rochelle) and
CEBC (Chizé).
Duration of the PhD: 3 years (from November 1st, 2026).
PhD student’s work programme:
• Bibliographic research
• Conducting field experiments and laboratory experiments
• Mandatory training in animal ethics
• Statistical analyses
• Valorisation of the results obtained (publication of scientific articles, presentation in
national and international congress, popular science…)
The PhD student may also participate in various group activities, carried out both within the
research team and the laboratories. Similarly, depending on the PhD student’s wishes,
teaching opportunities within the Biology Department of La Rochelle University may be
available.
PhD schedule:
The first year of the PhD will be devoted to defining the scope of the PhD, familiarising with
the bibliography and learn the various techniques that will be used in the field and in the
laboratory. The PhD student will also need to prepare for their first year of fieldwork, which
will take place from April to July. A review will therefore be carried out in August ahead of the
first PhD committee meeting, in order to define the focus for the second year.
To apply to this offer, send in a single file (PDF format):
– Your CV (including your ranking in your Bachelor’s degree, 1st year of Master and 2nd
year of Master, if available)
– A cover letter
– Your Master’s transcripts (1st and 2nd year)
Send the complete file to Elisa Thoral (elisa.thoral@univ-lr.fr) and Jérôme Moreau
(jerome.moreau@univ-lr.fr) before March 8.
If any question, please contact Elisa Thoral.
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