Examples of Foraging Strategies

One of the interesting issues is how much information from previous foraging bouts an animal can use to shape future bouts. I like studies of sit and wait predators such as web-weaving spiders, caddisflies, and certain kinds of snake because they provide an interesting contrast to the behavior of foragers that actively seek prey. Pasquet et al. (1999) find that it costs members of spider, Stegodyphus lineatus, 3-7% of their body mass to build a web that covers on average 150 cm2. The authors experimentally manipulated the spiders by either imposing a cost (web removal) or a benefit (food supplementation). Food supplemented spiders built smaller webs than did either control or web-removed spiders, indicating that level of investment in prey capture is adjusted in response to a higher capture rate. In a lab experiment most spiders who were not given prey maintained a web, while nearly 2/3 of those given three prey items did not construct a new web, indicating that fed spiders may be either satiated or reduce their exposure to risk by not building a new web. Other recent studies you might want to look at:

Bautista, L. M., J. Tinbergen, P. Wiersma, and A. Kacelnik. 1998. Optimal foraging and beyond: How starlings compe with changes in food availability. Am. Nat. 152:543-561.

Brown, J. S, J. W. Laundre and M. Gurung. 1999. The ecology of fear: optimal foraging, game theory and trophic interactions. J. Mammol. 80:385-399

Hirvoven, J., E. Ranta, H. Rita, and N. Peuhkuri. 1999. Significance of memory properties in prey choice decisions. Ecol. Model. 115:177-189.

Pasquet, A., R. Leborgne, and Y. Lubin 1999. Previous foraging success influences web building in the spider Stegodyphus lineatus. Behav. Ecol. 10:115-121