Consumer-Resource Interactions

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Consumer-Resource Interactions

Hunger, Health & Horror

To be announced

Scope

All organisms require inputs of energy and/or materials in order to grow and reproduce. Consumer-resource interactions in all its variations (i.e., plant-nutrient, plant-herbivore, predator-prey, host-parasitoid, and host-parasite) are central to ecological and evolutionary research. However, consumer-resource interactions are also the basis of exploitative competition (two or more consumers share resources), facilitation (one consumer increases resources for another) and many mutualisms (species trade 'resources'). Most organisms function as both consumers and resources in a food web. The functional and numerical responses of the consumer and a function describing resource population growth are essential components of any consumer-resource interaction. Understanding these responses often requires that we understand the adaptive processes - evolution, behaviour, and phenotypic plasticity - that shape these interactions on both short and long time-scales.

This one-week course will illustrate how adopting a consumer-resource approach can change our understanding of interactions, and how adaptive processes can be important in understanding both academic and applied problems in ecology. The course will focus on three selected topics within the field of consumer-resource interactions: Hunger, Health, and Horror. These topics will be introduced by world-renowned experts, with a focus on the latest developments and ongoing research efforts. The introductions will provide the starting point for practical work by the participants to make the acquired knowledge operational. To this end, sub-groups are challenged to develop ideas for their own research: analysing their own data, writing a proposal, planning an experiment, developing a model or writing a paper. The lecturers and organisers will be available to all groups during the practical work, allowing participants intensive interaction with them. The main goal of the course will be achieved if the participants acquire novel ideas and techniques for their own research.

Programme

On Sunday evening, we start with warming-up lectures by the organisers. Then, on Monday, the basics of consumer-resource interactions and the topics will be introduced. After that, work groups will be formed. During the following days, there will be lectures on specific topics, followed by discussion. The rest of the day will be spent on the practical work, under the supervision of the lecturers and the organisers. On the last day, the groups present their practical work to all participants.

The course will deal with the latest developments on the following issues:

  1. Hunger
    The mathematical models that underlie our understanding of both mutualistic and competitive interactions have traditionally expressed vital rates directly in terms of the population densities of interacting species. This is also true of density dependence, which is simply intraspecific competition. All of these processes almost invariably involve the dynamics of resources, yet, until recently, there has been little systematic exploration of how well these interactions have been represented by models that only implicitly reflect the use of resources by the population size of the competitors or mutualists. This section of the course will show how mutualistic and competitive interactions can be derived from models of the underlying processes of resource growth and consumption. It will explore the implications of these derivations for commonly accepted principles that have been derived based on models that lack such interactions. This will include a consideration of adaptive consumer behaviour and interactions between resources. The consequences of consumer-resource interactions for the impacts of environmental variation on population and community dynamics will also be discussed.
  2. Health
    Host-parasite and host-pathogen interactions are part of resource-consumer theory, but a distinctive part that is of growing importance. Infectious diseases can have consequences ranging from the behaviour and morphology of infected individuals, to impacts on population dynamics, to influences on species interactions and thus community structure. In the course, we will explore the interplay of resource-consumer dynamics and host-pathogen interactions, from several complementary perspectives. Infection occurs when a healthy host is occupied by a pathogenic organism, and this ‘occupation’ can have three distinct classes of effects upon that organism. First, the replication of this pathogen within the host requires utilization of resources within that host, and so the host and pathogen in effect ‘compete’ for a finite pot of resources needed to create and maintain biological structures. Beyond this, the pathogen in the course of replication can inflict direct damage on host tissues, so that as pathogen fitness rises, host survival, reproduction, or growth decline. Both these effects can be summarized as changes in host demographic rates as a function of infection status (or parasite ‘load’). We will review key aspects of the classical ‘SIR’ theory of infectious disease epidemiology, bringing out similarities and differences with predator-prey theory. Finally, the struggle between the host and pathogen can be modulated by both lower and higher trophic levels. The host’s ability to withstand infection will be determined by its own resource reserves, and the outcome of the interaction between the host and pathogen can be strongly influenced by host nutritional status. The rate of production of pathogens can be influenced by host resource status. Infectious disease can alter the ability of a consumer to compete effectively for limiting resources, and can also influence its capacity to escape and withstand attacks by predators. In many systems, trophic interactions themselves provide conduits for transmission of parasites. For all these reasons, an explicit consideration of resources, competition, and predation may often be vital for understanding host-pathogen dynamics. The course will provide an overview of recent work at this interface between epidemiology and community ecology.
  3. Horror
    When foraging, animals should and do demand hazardous duty pay. They assess a foraging cost of predation to compensate for the risk of predation or the risk of catastrophic injury. Similarly, in weighing foraging options, animals trade-off food and safety. The foraging cost of predation can be modelled, and it can be quantitatively and qualitatively measured using risk titrations. Giving-up densities (GUDs) in depletable food patches and the distribution of foragers across safe and risky feeding opportunities are two frequent experimental tools for titrating food and safety. A growing body of literature shows that: (i) the cost of predation can be big and comprise the forager's largest foraging cost, (ii) seemingly small changes in habitat or microhabitat characteristics can lead to large changes in the cost of predation, and (iii) a forager's cost of predation rises with risk of mortality, the forager's energy state and a decrease in its marginal value of energy. The course will introduce adaptive foraging under predation risk, and continue with fear responses and consumer-resource interactions and predator-prey foraging games.

The programme of the last edition of this course (October 2014) can be downloaded here.

Speakers

World-renowned experts / lecturers contributing to the course:

  • Joel Brown (University of Illinois at Chicago)
  • Bob Holt (University of Florida)
  • John Fryxell (University of Guelph)
  • Don DeAngelis (University of Miami)
 
Course organisers
  • Wolf Mooij (Aquatic Ecology, Netherlands Institute of Ecology)
  • Bart Nolet (Terrestrial Ecology, Netherlands Institute of Ecology)
  • Frank van Langevelde (Resource Ecology group, Wageningen University)
 
General information
 
Target Group The course is aimed at PhD candidates and other academics
Group Size Min. 25, max. 40 participants
Course duration 5 days
Language of instruction English
Frequency of recurrence Every three years
Number of credits 1.5 ECTS
Lecturers Prof. Joel Brown (University of Illinois at Chicago, USA), Prof. Bob Holt (University of Florida, USA), Prof. John Fryxell (University of Guelph, Canada), Prof. Don DeAngelis (University of Miami, USA), Prof. Wolf Mooij and Dr. Bart Nolet (Netherlands Institute of Ecology), Dr. Frank van Langevelde (Resource Ecology group, Wageningen University)
Prior knowledge Basic knowledge of consumer-resource interactions is required. Basic knowledge on modelling is helpful but not essential.
Location In-house, at a venue near Wageningen
More information

Claudius van de Vijver (PE&RC)
Phone: +31 (0) 317 485116
Email: claudius.vandevijver@wur.nl

Lennart Suselbeek (PE&RC)
Phone: +31 (0) 317 485426
Email: lennart.suselbeek@wur.nl

Registration of interest

At this moment, this course is not scheduled yet. However, if you register your interest in this activity below, we will inform you as soon as the course is scheduled and registration of participation is opened.