Download Laboratoire de Parasitologie Evolutive

Laboratoire de Parasitologie Evolutive
94
CNRS UMR 7103
Université Pierre et Marie Curie
Bât. A, 7ème étage
7 quai St. Bernard, Case 237
F-75252 Paris Cedex 5
France
Tel: ++ 33 1 44 27 25
Fax: ++ 33 1 44 27 35 16
Email: [email protected]
Stage M2
Predation and determinants of susceptibility to predation
Predation is one of the most important forces of natural selection, but relatively little is known
about the features that render particular individuals or species susceptible to predation. I
suggest a M2 project to investigate determinants of individual and specific susceptibility to
predation.
What are the factors that make individuals susceptible to predation?
1. Disease. A couple of recent studies have shown that individuals with a weak immune
system are more likely to fall prey to a predator (Møller & Erritzøe 2000). Predators may also
affect the immune status and hence the level of malarial parasites in potential prey through
effects on corticosterone (Møller et al. 2004). To which extent does immune responses reflect
risk of predation?
2. Inbreeding. Inbreeding generally reduces performance in a number of domains, and we
could test if prey have lower levels of heterozygosity than a sample of randomly chosen
individuals.
3. Secondary sexual signals. Such signals are often condition-dependent with individuals with
the largest signals being in superior condition. A few studies have shown that predators select
males with small secondary sexual characters (e. g. Møller & Nielsen 1997). Is this a general
phenomenon?
There are numerous studies of predation, but very few that have quantified predation relative
to abundance of prey in the environment. We have such a dataset covering well over 100
species of prey in several study areas that differ in quality. What are the factors that make
certain species susceptible to predation?
1. Disease. Preliminary studies suggest that species with strong immune responses are
suffering disproportionately from predation in years with poor weather conditions.
2. Inbreeding. Preliminary studies have shown that prey species with a high degree of band
sharing and hence with low levels of genetic variation have a disproportionately large risk of
falling prey to a predator. What is the mechanism behind this relationship?
3. Secondary sexual signals. Bird species that are sexually dichromatic are more likely to fall
prey to a predator than monochromatic species. What is the mechanism behind this
relationship?
Model systems: Predation by the European sparrowhawk Accipiter nisus and the European
goshawk Accipiter gentilis.
Existing databases include information on more than 80,000 prey items collected during a
period of 28 years from over 100 different breeding territories.
The study could be entirely based on analysis of existing data, or it could be partly or fully
based on fieldwork, including field experiments. There is also a possibility for a more
ecologically oriented project that emphasizes analysis of the determinants of interspecific and
spatial variation in determinants of numerical and functional response of different prey
species. Finally, it is possible to use a climate change point of view and investigate how
changes in climate affect predation risk, even in habitats that differ in quality.
Possibility for a PhD project if funding is available.
References:
Møller, A. P. & Erritzøe, J. 2000. Predation againts birds with low immunocompetence.
Oecologia 122:500-504.
Møller, A. P., Marzal, A., Navarro, C. and de Lope, F. 2004. Predation risk, host immune
response and parasitism. Behav. Ecol. 15:629-635.
Møller, A. P. & Nielsen, J. T. 1997. Differential predation cost of a secondary sexual
character: Sparrowhawk predation on barn swallows. Anim. Behav. 54:1545-1551.
Anders Pape Møller (DR1)