Physiological Entomology (2011) 36, 194-199

Jessica Vereijssen, Karen F. Armstrong, Barbara I.P. Barratt, Allan M. Crawford, Mark R. McNeill and Stephen L. Goldson (2011)
Evidence for parasitoid-induced premature mortality in the Argentine stem weevil
Physiological Entomology 36 (2), 194-199
Abstract: The Argentine stem weevil Listronotus bonariensis Kuschel (Coleoptera: Curculionidae) is an exotic pest of New Zealand ryegrass and the adult-stage is parasitized by the introduced solitary endoparasitoid Microctonus hyperodae Loan (Hymenoptera: Braconidae: Euphorinae). This biological control agent is effective, although, under both laboratory and field conditions, an unexplained source of premature mortality in the weevils is observed after exposure to M. hyperodae. This premature mortality may be affected to varying degrees by the length of time of parasitoid exposure, the physiological conditions of the host, and the host to parasitoid ratios, although it occurs naturally without any physical interruption to the parasitoid ovipositional process. In the present study, the premature mortality reported in earlier studies is confirmed and it is conjectured to be the result of injection of parasitoid venom without an egg. Moreover, the lack of premature mortality resulting from longer exposure periods indicates that there might be a curative effect resulting from subsequent oviposition; the egg reverses the toxic effect induced by the injection of venom only. As discussed, this phenomenon may not be restricted to the L. bonariensis/M. hyperodae system and, accordingly, there are evolutionary, biosecurity and general pest management questions to be considered.
(The abstract has been supplied by the author or ISPI and is excluded from the Creative Commons licence.)
(original language: English)
Link to article at publishers website
Database assignments for author(s): Allan M. Crawford

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Listronotus bonariensis		New Zealand
Microctonus hyperodae (parasitoid)	Listronotus bonariensis		New Zealand