Postdoc Project either on
Reproductive Competition and Sociality
or alternatively on
Environmental harshness and social stress
(NOTE:
We also advertise 2 paid positions as field managers for 1.5 to 4
years, and unpaid volunteer positions for 2-12 months. See other
advertisements or ask via email carsten.schradin@iphc.cnrs.fr)
We are looking for a highly motivated postdoc to join the striped mouse project www.stripedmouse.com
and our group at the University of the Witwatersrand (Johannesburg). The
postdoc is paid via a grant of the South African NRF for two years from
Prof. Neville Pillay at the University of the Witwatersrand. The
postdoc is expected to spend most of the time at the Succulent Karoo
Research Station, conducting field work, analysing and publishing data.
We
have two possible projects for a postdoc. Both projects are of similar
interest to us. When applying, please state for which of the two
projects you apply.
Project 1: Reproductive Competition (Seasonal Unpredictability and Social Flexibility)
For
this project, a long-term dataset on social organisation of striped
mice will be available for analyses (from 2003 to present) and further
data collection will extend to 2021. Sociality (% of solitary versus
group-living striped mice) will be studied in relation to population
density and the intensity of reproductive competition, which is (i) very
high during the spring breeding season when all females breed, (ii)
absent during most summer dry seasons, (iii) low during summers with
unexpected rains when few females breed (6 out of 17 summers in the
current data set).
Questions and predictions: We
expect that reduced reproductive competition during summer breeding
will lead to more social instability in spring compared to summer, i.e.
groups to be more stable in summer. We will also study which factors
differ between females that breed during the summer vs. females that
don’t. Finally, the impact of rare summer breeding on population
dynamics will be studied.
Time planning: Preferred
start is July 2020 and the position must be started in 2020. The
postdoc is expected to be in the field for most of the time but can plan
two slots of 3 months each to spend at the University of the
Witwatersrand.
Project 2: Environmental harshness and social stress in a biodiversity hotspot: corticosterone might not be the only nor the best measure
Animals
have to cope with harsh environments and with stress but these
phenomena are not synonymous. Stress is the activation of the
sympathetic nervous system (SNS) and the hypothalamic-pituitary (HPA)
axis, leading to the secretion of catecholamines and glucocorticoids,
providing extra energy to overcome the stressor inducing stress.
Environmental conditions are termed harsh when they are long-lasting and
life threatening, such as seasonal food shortage. Thus, while harshness
demands energy saving, stress demands increased energy expenditure,
predicting that the stress response will change as environmental
harshness changes. In our study model, the African striped mouse Rhabdomys pumilio,
we will measure several indicators of stress under varying conditions
of harshness, some for the first time in an eco-physiological framework.
We will evaluate three different aspects to differentiate between
effects of harshness (dry season) and social stress (reproductive
competition during the moist season) on survival, and fitness. These
include: 1) neuropeptide y as an indicator of sympathetic activity and
thus short-term stress; 2) corticosterone as an indicator of mid-term
investment in increased energy expenditure; 3) Measures of resting
metabolic rate and how these are related to corticosterone levels. Our
study will be the first to assess how the stress response adapts to
environmental harshness, predicting that in the harsh dry season, the
HPA axis will be downregulated, while the response of the SNS will not
change seasonally, allowing for an immediate response to life
threatening events such as predation. Thus, we predict an adaptive
desynchronization of the SNS and the HPA axis, a phenomenon so far only
described as pathology in humans. This project will contribute
fundamentally to our understanding of how to distinguish harshness from
stress and how animals can cope with these two phenomena adaptively via
different mechanisms.
Time planning: Preferred
start is July 2020 and the position must be started in 2020. The
postdoc is expected to be in the field for most of the time but can plan
to spend 1-2 months in Strasbourg (France) for laboratory analyses and 4
months at at the University of the Witwatersrand.
Key requirements:
Strong statistical skills. Strong CV with 3 publications from the PhD
and at least 1 publication per year from postdoc studies, some of them
in high ranking journals (impact factor >3). Willingness to spend
considerable time in the field in South Africa. Ability to analyse data
and to write manuscripts while being field based.
What you will learn: Strong field skills and understanding of theory underlying social evolution / eco-physiology of stress.
How to apply: In a single PDF, send a letter of motivation, your academic CV, and contact details of a minimum of 2 (better more) referees to Carsten Schradin, carsten.schradin@iphc.cnrs.fr and Neville Pillay, neville.pillay@wits.ac.za.
Application deadline: Skype interviews will be held beginning of March, so best send your application latest the 17th February, giving us time to contact your referees for a letter of reference. If necessary, a second call will be published in March 2020.
More information: