Evol Ecol Res 5: 701-716 (2003)     Full PDF if your library subscribes.

Optimal tempo and defence for consumers of multiple resources

Adam Kay1* and Frederick R. Adler1,2

1Department of Biology and 2Department of Mathematics, University of Utah, Salt Lake City, UT 84112, USA

Address all correspondence to Adam Kay, Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA.
e-mail: kayxx011@umn.edu

ABSTRACT

Ecological models of behaviour are typically based on the assumption that decisions can be evaluated with a single resource currency. Here we present models that predict the tactics of consumers collecting two nutritionally distinct resources: fuel that is used for activity and food used for growth (F4G). Both models assume that foragers seek to maximize F4G gain subject to collecting enough fuel for activity. Our first model determines the optimal tempos of foraging for each resource. While foraging for fuel, consumers use and collect the same resource and optimal behaviour is identical to the predictions of a single resource model. However, because consumers use fuel to acquire F4G, they are predicted to work harder to acquire F4G when fuel is more available. Our second model examines how consumers should allocate their time among foraging for fuel, foraging for F4G and defence of F4G sources. Optimal investment in defence increases when fuel is available (because expenditures can be quickly recovered) and when F4G is scarce (because fewer opportunities exist for obtaining new sources of F4G). Our results suggest that behaviours will appear wasteful when foraging environments are fuel-rich and overly frugal when F4G is common but fuel is scarce.

Keywords: defence, optimal foraging, provisioning, tempo.

DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.

 

        © 2003 Adam Kay. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.