New Zealand Journal of Agricultural Research abstracts

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Multitrophic interaction between the ryegrass Lolium perenne, its endophyte Neotyphodium lolii, the weevil pest Listronotus bonariensis, and its parasitoid Microctonus hyperodae

S. L. GOLDSON
J. R. PROFFITT
L. R. FLETCHER
D. B. BAIRD

AgResearch
P.O. Box 60
Lincoln, New Zealand
Email: goldsons@agresearch.cri.nz

Abstract  Field experiments in Canterbury, New Zealand, investigated four levels of interaction involving the clavicipitaceous endophytic fungi Neotyphodium lolii measured as ppm of the alkaloid peramine in bulked samples of Lolium perenne, the weevil pest Listronotus bonariensis, and its braconid parasitoid Microctonus hyperodae. Weevil numbers were unusually low and the expected inverse relationship between ground densities and peramine concentration was not observed. There was, however, a highly significant tritrophic interaction whereby percent parasitism was inversely related to ppm of peramine. Possible mechanisms for this interaction are discussed and it is suggested that it may have been the result of reduced feeding intensity of L. bonariensis that led to a corresponding reduction in opportunity for the parasitoid to attack.

Keywords  Lolium perenne; Neotyphodium lolii; Listronotus bonariensis; Microctonus hyperodae; multitrophic interaction

New Zealand Journal of Agricultural Research 2000, Vol. 43: 227-233

0028-8233/00/4302-0227 $7.00/0 (c) The Royal Society of New Zealand 2000

PDF file of entire paper: medium quality (578K); (scanned from paper original: notes about this process)

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