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INTRAGUILD PREDATION AMONG APHID PREDATORS: CHARACTERIZATION AND INFLUENCE OF EXTRAGUILD PREY DENSITY
Author(s) -
Lucas Éric,
Coderre Daniel,
Brodeur Jacques
Publication year - 1998
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(1998)079[1084:ipaapc]2.0.co;2
Subject(s) - intraguild predation , chrysopidae , aphid , biology , predation , coccinellidae , cecidomyiidae , ecology , neuroptera , aphididae , predator , botany , larva , homoptera , pest analysis
Intraguild predation (IGP), a common interaction in invertebrates and vertebrates, affects the abundance and distribution of many species. Several parameters influence the magnitude and direction of IGP: feeding specificity, size, mobility, and aggressiveness of the protagonists, as well as extraguild prey density. Under laboratory conditions, we studied IGP among three species of aphid predators, Aphidoletes aphidimyza (Diptera: Cecidomyiidae), Chrysoperla rufilabris (Neuroptera: Chrysopidae), and Coleomegilla maculata lengi (Coleoptera: Coccinellidae), which commonly attack the potato aphid (extraguild prey) Macrosiphum euphorbiae (Homoptera: Aphididae). We characterized the levels and symmetry of IGP among the various stages of the predators in the absence of extraguild prey. The aphid specialist A. aphidimyza was more vulnerable to IGP than C. rufilabris and C. maculata, two generalist predators. The C. maculata / C. rufilabris interaction was symmetric (mutual IGP), whereas the C. maculata / A. aphidimyza and C. rufilabris / A. aphidimyza interactions were asymmetric, in favor of the coccinellid and the lacewing, respectively. Sessile and low mobility stages of all species were extremely vulnerable to IGP. Generally, the larger sized individual won confrontations. For similar sizes, lacewing larvae were superior to coccinellid larvae. We also tested whether IGP decreases when extraguild prey are introduced into the system. Data from five predator combinations revealed three types of responses: (1) an exponential decrease in IGP (lacewing instar I vs. coccinellid instar I); (2) a constant IGP (lacewing instar III vs. coccinellid instar I); (3) a constant IGP at low densities decreasing at high densities (lacewing instar III vs. gall midge old larva). Four theoretical scenarios are derived from these responses. Each is discussed according to the ecological attributes of the protagonists. This study shows that IGP is influenced by factors inherent to the predators and external factors such as extraguild prey density. The results are discussed further in the context of aphid biological control.