Ernst Strüngmann Forum


Evolutionary and Economic Strategies for Benefitting from Other Agents’ Investments

November 1–6, 2015

Frankfurt am Main, Germany

Luc-Alain Giraldeau and Philipp Heeb, Chairpersons

Program Advisory Committee

Luc-Alain Giraldeau, Faculty of Science, Université du Québec à Montréal, succursale Centre-ville, Montréal, Québec H3C 3P8, Canada
Philipp Heeb, Université Paul Sabatier, Laboratoire Evolution et Diversité Biologique (EDB), UMR 5174 CNRS-UPS, Toulouse Cedex 4, France
Alex Kacelnik, Behavioural Ecology, Department of Zoology, Oxford University; Oxford OX1 3PS, U.K.
Michael Kosfeld, Organization and Management, Goethe University Frankfurt, Grüneburgplatz 1, 60323 Frankfurt, Germany
Julia Lupp, Ernst Strüngmann Forum, Ruth-Moufang-Str.1, 60438 Frankfurt, Germany
Frédéric Thomas, MIVEGEC - Centre IRD de Montpellier, 911 Avenue Agropolis, BP 64501, 34394 Montpellier cedex 5, France


  • To explore real-life cases and theoretical models that deal with impacts of “social parasitism” in humans and other organisms.
  • To bring together evolutionary biologists, economists and other social scientists to benefit from commonalities between them.
  • To work toward a common synthesis that would promote a unified framework and explore implications for public health, natural resource use, and the design of institutions.

We will approach these goals from four perspectives:

  • Ecological and Economic Conditions of Parasitic Strategies
  • Governance of Natural Resources
  • Human Health
  • Consequences for Individual Behavior, Social Structure, and Design of Institutions
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When goal-driven agents, such as humans, other organisms, or institutions, seek resources (including services or information) in the presence of others, they can invest effort directly to obtain the resource or indirectly, by exploiting others’ producing activity. Such situations of “social parasitism” create social dilemmas where some individuals pay production costs whilst others can obtain some benefits through some form of free-riding. In foraging ecology such strategies have been studied, for example, using the game-theoretical model known as “producers and scroungers,” but many other models that concern social and economic interactions also address these problems.

Examples of real-life systems where the problem is prevalent include:

  • Some species provision their dependent offspring while others specialize on letting offspring be nourished by members of other species.
  • In humans, cooperation and solidarity norms develop that can sometimes provide opportunities for free-loading and exploitation.
  • Governments affect their own countries’ climate prospects by managing their own greenhouse emissions and by attempting to impose restraint on other countries.
  • Individuals can influence their own probability of infection by vaccination or indirectly by taking advantage of the lowered disease incidence that results from the vaccination of others.
  • Among cancerous cell societies, some cancerous cells stimulate angiogenesis in tumors while others benefit from the extra oxygen and nutrients, without investing in the stimulants.
  • Among manipulative parasites, not all individuals within a given host invest energy into the manipulative effort but all benefit from the changes induced in the behavior of the host.
  • The use of antibiotics combats infection but also increases pathogen resistance through natural selection. The therapeutic benefit to the individual often feeds on the restrained use of the antibiotic by others.
  • In natural resource use, humans can pay the cost of being ecologically prudent and/or address effort to impose frugality in others.

We aim to promote integration between studies in these different contexts, extracting lessons that could inform action where human interests are involved (e.g., in conservation, public health, market stability, etc.). This Forum will discuss case studies, compare alternative modeling approaches and explore the potential for regulation environments.

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