Spread of the wasp parasitoid Sphecophaga vesparum vesparum following its release in New Zealand
- Biological Control Group, AgResearch, P.O. Box 60, Lincoln, New Zealand
- Landcare Research, Private Bag, Nelson, New Zealand
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
The measurement of parasitism rates of wasp nests;lt Pelorus Bridge, New Zealand, at different distances from the initial release point suggests that the mean displacement of the parasitoid has increased by 1—1.5 km y(-1) from 1988 to 1993. Since average parasitism rates within this radius at any given site show little trend over time, this suggests an approximate 3-fold increase in the total parasitoid population each year, two-thirds of which is devoted to dispersal and one-third to maintaining local populations.