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26 March 2004
The Ministry of Agriculture and Forestry (MAF) will be conducting local
visual surveillance activities in Raglan looking for signs of median wasp (Dolichovespula
media) nests, following the submission of a specimen by a local entomologist.
The entomologist noticed the unusual wasp buzzing against a window of a
Raglan home in the summer of late 2002, it was caught and placed in a freezer
(to kill it). Recently, after two years, the wasp was rediscovered when the
freezer was being cleaned. The wasp was then submitted to MAF and identified as
a median wasp.
"This is the first time a median wasp has been found in New Zealand" said
Amelia Pascoe, MAF Programme Co-ordinator Exotic Animal Response. "This wasp is
believed to have originated from a nest of overseas origin as it was found in
early December. A local nest would not be expected to produce males until
several months later in the autumn (March).
"It is not known where the wasp came from, but one scenario is that iron-sand
carriers from Japan, which work along the Raglan section of coastline,
introduced the wasp from a nest on board. The wasp could have been blown, or
flown to land" said Ms Pascoe.
While MAF considers it unlikely that this specimen represents an established
population, the visual search will be conducted as a precaution. MAF has also
drafted an information sheet for distribution to the local entomological
community, regional council and Department of Conservation.
Median wasps have less yellow than other New Zealand based social wasps and
have a distinctive reddish-brown appearance with brown tinted wings. It is also
considerably larger, ranging between 16 to 22 mm in length.
If it were to establish in New Zealand, the median wasp (like other vespid
wasps), could prey on native flies and moths, providing direct competition for
honeydew resources to New Zealand's nectar feeding birds.
The human health risk from the median wasp is similar to that of wasps
already present in New Zealand.
Fore more information on how to distinguish the median wasp and its nest from
other New Zealand established wasps and for information on how to treat wasp
stings go to
If anyone finds what they believe is median wasp nest, or a median wasp,
please call the MAF Exotic Disease and Pest Emergency Hotline 0800 809 966.
Joseph Wallace, MAF Assistant Communications Adviser
Phone: 0-4-498-9637 or 021-159-7192