Item – Theses Canada

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OCLC number
46529837
Author
Li, Chao,1952-
Title
The foraging behavior of a parasitoid wasp, Aphelinus asychis : a modelling approach.
Degree
Ph. D. -- Simon Fraser University, 1993
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, 1994.
Description
2 microfiches.
Notes
Includes bibliographical references.
Abstract
Foraging by the solitary parasitoid wasp, Aphelinus asychis Walker (Hymenoptera: Aphididae, Aphelinidae) for its pea aphid host, Acyrthosiphon pisum Harris (Homoptera: Aphididae), on broad beans, Vicia faba L. cv. 'Broad Windsor', was examined in the laboratory. The process was studied within and between patches. Within patches, the wasp searches randomly. Once a female wasp enters a patch, two kinds of behavioral "decisions" are made: host acceptance and patch leaving. The patch leaving decisions are apparently based on the identities of the last five hosts encountered which are stored in a "sliding memory window". When the proportion of parasitized, unacceptable hosts in the last five encounters exceeds 50%, or the wasp does not encounter any hosts within the initial giving-up-time, it leaves its current patch. A female wasp can make three possible decisions upon encountering an aphid host: to lay an egg in the host; to feed on it; or to reject it. Decisions for accepting a host are optimally made with a success rate of 0.2. Host feeding can be described by a periodic function. Wasps tended to search for patches on the same horizontal layer. The tendency to move upward was slightly greater in wasps with foraging experience than in those without experience. When a wasp is forced to search on an extended surface, its movement pattern between patches can be described by an area-restricted search or a random walk with limited time steps, with the length of each step being small relative to the surface. A three-dimensional simulation incorporating all the information available about the system demonstrates that the model can predict the parasitism of A. asychis of its pea aphid hosts. The study also showed that theory-driven simulations can be used in syntheses using information from an experimental system to demonstrate how to scale information from a lower level (within patches) to a higher level (between patches). This approach is useful for exploring possible population consequences of foraging processes.
ISBN
0315910852
9780315910850