Bulletin of Entomological Research (1999) 89, 347-353

S.L. Goldson, J.R. Proffitt, M.R. McNeill and D.B. Baird (1999)
Linear patterns of dispersal and build up of the introduced parasitoid Microctonus hyperodae (Hymenoptera : Braconidae) in Canterbury, New Zealand
Bulletin of Entomological Research 89 (4), 347-353
Abstract: The dispersal of Microctonus hyperodae Loan, an introduced parasitoid of the South American grassland pest Listronotus bonariensis Kuschel, was measured in Canterbury, New Zealand. Considering all directions, the mean annual dispersive increment was 1.9 ± 0.9 km year^-1 as measured in the winters of 1993, 1994 and 1995. The parasitoid's ground distribution suggested that its movement was biased towards the south-west indicating probable wind-borne dispersal. The overall relatively low rate of dispersal was thought to be related to the inhibitory effects of M. hyperodae parasitism on L. bonariensisflight. A generalized linear model fitted to percentage of L. bonariensisparasitized took a simple form, with a quadratic increase in weevil infection, that with time, gradually decreased. The build-up of parasitism at the release site was significantly greater than the rates at the other sites measured in this study (P< 0.001) with a ratio of release site: dispersal site rates of 1.33: 1. The simplicity of the fitted generalized linear model indicated remarkable uniformity in both parasitism build-up and dispersal from one year to the next; this finding indicated that all dispersal was 'natural' and unassisted by human activity. Despite such modest dispersal rates, by the winter of 1996, five years after its release, the parasitoid had spread geometrically over an area of c. 140 km².
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Stephen L. Goldson, Mark R. McNeill

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
transmission/dispersal
population dynamics/epizootiology

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Pest and/or beneficial records:

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