Central place foraging for non-food items : determination of the stick size-value relationship of house building materials collected by eastern woodrats
Document Type
Journal article
Source Publication
American Naturalist
Publication Date
6-1984
Volume
123
Issue
6
First Page
841
Last Page
853
Publisher
University of Chicago Press
Abstract
Up to now optimal foraging theory has dealt exclusively with animals foraging for food. The currencies used to measure the benefit of food items, energy and nutrients, are inappropriate measures of the benefit of nonfood items collected by animals. This paper proposes that "value" can be used as a currency for nonfood items and presents a procedure for determining the size-value relationship of nonfood items. This procedure was used to determine the stick size-value relationship of sticks collected by eastern woodrats as house building materials. Simulations of profitability [(V-C)/T] versus distance curves for five general stick size-value relationships predict that regardless of the stick size-value relationship, the number of stick sizes above the minimum profitability value decreases with distance from the central place. This prediction was supported in a laboratory experiment. Woodrats were also found to collect more selectively (decreased variance) as they collect farther from the house. Since the woodrats were foraging adaptively, taking only those sticks above the minimum profitability value, it was possible to use stick-size preference to select between the five general relationships. It was determined that there is an increasing relationship between stick size and value for woodrats initiating house building. Since it is possible to select between the five relationships it should often be possible to use this technique to determine the size-value relationship for nonfood items collected by animals when the object size is the most important factor determining value.
DOI
10.1086/284243
Print ISSN
00030147
E-ISSN
15375323
Publisher Statement
Copyright © 1984 University of Chicago Press. Access to external full text or publisher's version may require subscription.
Full-text Version
Publisher’s Version
Language
English
Recommended Citation
McGinley, M. A. (1984). Central place foraging for non-food items : determination of the stick size-value relationship of house building materials collected by eastern woodrats. American Naturalist, 123(6), 841-853. doi: 10.1086/284243