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Parasitism of the herbivore Pieris brassicae L. (Lep., Pieridae) by Cotesia glomerata L. (Hym., Braconidae) does not benefit the host plant by reduction of herbivory
Author(s) -
Coleman R. A.,
Barker A. M.,
Fenner M.
Publication year - 1999
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1046/j.1439-0418.1999.00334.x
Subject(s) - biology , braconidae , pieris brassicae , parasitoid , pieridae , herbivore , parasitism , parasitoid wasp , botany , host (biology) , biological pest control , ecology , larva
Models of tritrophic interactions often imply that attraction of herbivore natural enemies by the plant constitutes a defence. Parasitoid attack on herbivores is assumed to result in a reduction in herbivory and/or an increase in plant fitness. Coupled with the active involvement of the plant in producing signals, this can be seen as indirect mediation of wound‐induced defence. The assumption that parasitism of Pieris brassicae L. by the parasitoid Cotesia glomerata L. reduces leaf consumption of cabbage is tested. The effect of parasitism on the growth and feeding rates of P. brassicae larvae compared to unparasitized larvae. Either the defensive mechanism, if it exists, is more subtle, or the natural enemy is using an incidental chemical produced as a by‐product of the herbivores feeding action as a cue for host‐finding, with no increaction effects. This has implications for the study of tritrophic interactions, particularly in the context of agricultural systems and the assumption that in IPM strategies, parasitoids are a plant benefit.