, Volume 78, Issue 4, pp 542–549

Stochastic prey arrivals and crab spider giving-up times: simulations of spider performance using two simple “rules of thumb”

  • Peter Kareiva
  • Douglass H. Morse
  • Jill Eccleston
Original Papers


We compared the patch-choice performances of an ambush predator, the crab spider Misumena vatia (Thomisidae) hunting on common milkweed Asclepias syriaca (Asclepiadaceae) umbles, with two stochastic rule-of-thumb simulation models: one that employed a threshold giving-up time and one that assumed a fixed probability of moving. Adult female Misumena were placed on milkweed plants with three umbels, each with markedly different numbers of flower-seeking prey. Using a variety of visitation regimes derived from observed visitation patterns of insect prey, we found that decreases in among-umbel variance in visitation rates or increases in overall mean visitation rates reduced the “clarity of the optimum” (the difference in the yield obtained as foraging behavior changes), both locally and globally. Yield profiles from both models were extremely flat or jagged over a wide range of prey visitation regimes; thus, differences between optimal and “next-best” strategies differed only modestly over large parts of the “foraging landscape”. Although optimal yields from fixed probability simulations were one-third to one-half those obtained from threshold simulations, spiders appear to depart umbels in accordance with the fixed probability rule.

Key words

Foraging Rules of thumb Spider Stochastic model Yield profile 


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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Peter Kareiva
    • 1
  • Douglass H. Morse
    • 2
  • Jill Eccleston
    • 3
  1. 1.Department of Zoology, NJ-15University of WashingtonSeattleUSA
  2. 2.Graduate Program in Ecology and Evolutionary Biology, Division of Biology & MedicineBrown UniversityProvidenceUSA
  3. 3.Department of EntomologyCornell UniversityIthacaUSA

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