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Relative roles of top‐down and bottom‐up forces in terrestrial tritrophic plant–insect herbivore–natural enemy systems
Author(s) -
Walker Matthew,
Jones T. Hefin
Publication year - 2001
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1034/j.1600-0706.2001.930201.x
Subject(s) - herbivore , ecology , insect , biology , abundance (ecology) , natural (archaeology) , top down and bottom up design , confusion , paleontology , psychology , software engineering , psychoanalysis , engineering
Whether resources (bottom‐up forces), natural enemies (top‐down forces), or both, determine the abundance of insect herbivore populations in plant–insect herbivore–natural enemy systems remains a major issue in population ecology. Unlike recent surveys of the tritrophic literature we do not seek to quantify whether top‐down or bottom‐up forces predominate in any given set of experimental systems. Acknowledging the dearth of empirical synthesis we employ two contrasting literature surveys to determine whether the plant–insect herbivore–natural enemy literature is currently adequate to form a conceptual synthesis of the relative roles of top‐down and bottom‐up forces.
The emergence of a synthesis of the relative roles of top‐down and bottom‐up forces in plant–insect herbivore–natural enemy systems appears to have been largely prevented by (1) the absence of appropriate empirical data; (2) failure to appreciate the merits of existing data; (3) a continued desire to emphasise either top‐down or bottom‐up forces to the exclusion of the other; and (4) confusion regarding which processes regulate and which influence the abundance of insect herbivores.