Annuaire IPHC

DEPE | Stratégie scientifique » Ethologie et Physiologie Evolutive (EPE) » Carsten Schradin

Carsten Schradin

Behavioral and Physiological Flexibility
to Succeed in a Changing World.

Director of Research (DR2) at the CNRS ; Titularporfessor at the University of Zurich ; Honorary Professor at the University of the Witwatersrand ; Director of the Succulent Karoo Research Station.


Twitter : @CarstenSchradin

  Research

I want to understand evolved physiological mechanisms which allow animals to behave adaptively in their changing natural environment. I study how changes in the endocrine system allow animals to cope with change by adapting their physiology, especially metabolism, osmoregulation, reproduction, and their behavior. I am interested in social behavior and why group-living, paternal care and helping behavior evolved, how it is regulated physiologically, and how it enables species to cope with challenging environmental conditions. This includes challenges of the social environment. As such, I am interested in understanding conflict and cooperation. My projects focus on three research questions :

  • Research question 1 : How is hormone secretion influenced by the environment and how does this influence physiology, behavior and fitness ?
  • Research question 2 : How does the trade-off between conflict and cooperation change with environmental change (e.g. seasonality, changes in population density) and how does this influence sociality ?
  • Research question 3 : When and why did intra-specific variation in social organisation evolve ?

Project 1 : Behavioral and Physiological Flexibility in African Striped Mice

 
I want to understand how social and physiological flexibility allows striped mice to optimize individual fitness in an extreme environment. Hereby I regard physiology as an evolved trait that has direct fitness consequence.

Project 1 : Behavioral and Physiological Flexibility in African Striped Mice

My main study species is the African striped mouse, which shows high social flexibility, ranging from solitary living to living in extended family groups. It occurs in the Succulent Karoo semi-desert of South Africa which is characterized by cold wet winters and hot dry summers. I want to understand how social and physiological flexibility allows striped mice to optimize individual fitness in this extreme environment. Hereby I regard physiology as an evolved trait that has direct fitness consequence, for example via changes in metabolism, osmoregulation, and reproduction. Additionally, physiological changes, especially of the endocrine system, can also modulate behaviour, leading to an adaptive behavioural response. My work has generated three major findings that are of importance to further develop concepts and theory.

  1. The first good empirical data from long-term studies and from field experiments to show that reproductive competition is one of the main reasons for solitary-living (Schradin et al, 2010 ; Schoepf & Schradin, 2012).
  2. I developed the concept of the single strategy from our results that the fitness consequences of alternative reproductive tactics can differ between generations, depending on the generation specific ecological conditions (Schradin & Lindholm, 2011).
  3. The concept of social flexibility was developed, which is a form of reversible phenotypic plasticity where the social system of an entire population can change facultatively as a function of individuals of both sexes changing their social tactics depending on ecological conditions (Schradin et al., 2012 ; Schradin 2013).

My studies are done at the Succulent Karoo Research Station (SKRS), a registered South African non for profit organisation, which was founded by me and of which I am the director. SKRS is based in the Goegap Nature Reserve. SKRS aims to increase our knowledge about the ecology of the Hardeveld of Namaqualand with special reference to the important role of small mammals. The Research Station offers a convenient and pleasant workplace for scientists from all over the world in a unique environment. The work at SKRS is done in collaboration with Prof. Dr. Neville Pillay from the University of the Witwatersrand.

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Project 2 : Intra-specific Variation in Social Organisation

 
I study why IVSO evolved (environmental and life history traits associated with the occurrence of IVSO), and how taking IVSO into account changes our understanding of social evolution, for example the evolution of monogamy and cooperative breeding.

Project 2 : Intra-specific Variation in Social Organisation

Many species show intra-specific variation in their social organization (IVSO), which means the composition of their social groups can change between solitary living, pair-living or group-living. It has long been realized that the environment plays a key role in explaining the occurrence of IVSO. However, studying only the environmental factors is not sufficient, as four different mechanisms exist that can lead to IVSO, each of which depends on the environment : environmental disrupters, genetic differentiation, developmental plasticity, and social flexibility. Only three mechanisms represent evolved mechanisms, while environmental disrupters induce non-adaptive IVSO. IVSO is important to take into consideration when studying social evolution (evolution of monogamy, cooperative breeding, paternal care, group versus solitary living), as not every species can be assigned to one single form of social organization. For such comparative studies, it is important to have reliable data-bases based on the primary literature. IVSO is an interesting phenomenon that needs scientific explanation. Understanding IVSO is important because it demonstrates species resilience against environmental change and it can help us to study ultimate and proximate reasons of group-living by comparing between solitary and group-living individuals in a single species. Together with Loren D. Hayes I study why IVSO evolved (environmental and life history traits associated with the occurrence of IVSO), and how taking IVSO into account changes our understanding of social evolution, for example the evolution of monogamy and cooperative breeding.

Project 3 : Social Organisation in Mammals

 
In the last few decades, the focus in animal behaviour has been theory based research, with little attention for descriptive studies. To obtain good comparative databases for theory-driven research, we need high quality field studies, including studies describing the social system of species.

Project 3 : Social Organisation in Mammals

Shrews and their close relatives (order Eulipotyphla) were typically considered to be solitary. In a review about field studies done on shrews and their close relatives (order Eulipotyphla, the third largest mammalian order) we found 56% of the studied species to be social, which is in sharp contrast to the 0.5% and 8% reported in other databases. However, reliable field data were only available 16 of the 445 species, and in other mammalian orders such as rodents the situation is not much better. To understand the social evolution of mammals, comparative studies must be based on reliable and specific information, and more species of all orders must be studied in the field.

In the last few decades, the focus in animal behaviour has been theory based research, with little attention and funding for descriptive studies. However, the quality of comparative studies not only depends on R programming abilities, but also on the quality of the data used. To obtain good comparative databases for theory-driven research, we need high quality field studies, including studies describing the social system of species. There have been requests to increase efforts and funding for describing the world’s biodiversity taxonomically. Similarly, we should also increase our efforts to describe the biodiversity of social systems if we believe social evolution is an important topic of research. We therefore started to study the social organisation of other small mammals on our field site. We showed that round-eared elephant shrews (Macroscelides proboscideus) are pair-living . Currently we are starting on long-term project on the social system of bush Karoo rats (Otomys unisulcatus).

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  Research team

Research manager : Florian Drouard
Station manager : Richard Askew
Dr. Rebecca Rimbach, postdoc.
Dr. Pauline Vuarin, postdoc

Several field assistants and master students.

  Previous group members and students

See Previous group members

  Ongoing Collaborations

  • Dr. S. Blanc, Institut Pluridisciplinaire Hubert Curien Strasbourg (CNRS), Départment Ecologie, Physiologie et Ethologie. Ecophysiology, metabolism, stable isotopes.
  • Dr. Francois Criscuolo, Institut Pluridisciplinaire Hubert Curien Strasbourg (CNRS), Départment Ecologie, Physiologie et Ethologie. Aging and telomere evolution in striped mice.
  • Prof. Dr. L.D. Hayes, University of Tennessee at Chattanooga (USA). Intra-specific variation in social organization of mammals.
  • Dr. A. Lindholm, Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Switzerland. Socio-genetics of Rhabdomys pumilio.
  • Prof. Dr. A. Ozgul, Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Switzerland. Demographic and phenotypic signals of population responses to environmental change
  • Prof. N. Pillay, University of the Witwatersrand, South Africa. Socio-ecology of Rhabdomys pumilio.
  • Prof. Dr. R. Straub, University of Regensburg, Germany. Evolutionary medicine.
  • Prof. Dr. H.E. Hoekstra, Harvard University. The evolution and development of stripes in striped mice.
  • Prof. Dr. J. Ganzhorn, University of Hamburg, Germany. Determining nutritional content of food plants.

  Media Coverage

See http://stripedmouse.com/site1_2_3.htm

  Institutional Coverage

  Short CV

2014- Researcher (DR2-CNRS) IPHC
2012- Researcher (CR1-CNRS) IPHC
2006-2012 Independent Group Leader University of Zurich
2001-2005 Post-Doctoral Fellow University of the Witwatersrand
1997-2001 PhD University of Zurich
1997-2001 MsC thesis Max-Planck Institute for Behavioral
Physiology, Seewiesen
1994-1997 MSc Ludwig-Maximilians University Munich
1992-1994 BASc University of Hohenheim

  Work Address

CNRS - University of Strasbourg,
Institut Pluridisciplinaire Hubert Curien
Département Ecologie, Physiologie & Ethologie
23 rue Becquerel
67087 Strasbourg Cedex 2 France
Phone : +33 (0) 388 10 69 19
Fax : +33 (0) 388 10 69 06
e-mail :

Project homepage : www.stripedmouse.com
Twitter : @CarstenSchradin
Facebook Striped Mouse Project : www.facebook.com/groups/stripedmouse/
Facebook Eco-Physiology : www.facebook.com/groups/1502219050044338/
Facebook Mammals of the World : /www.facebook.com/groups/mammalian/