He has also pointed out several ant species continued to forage more actively in the city during the past winter than they had for more than 40 years, and recently remained more active than usual.
More German and common wasps also seemed to have spent winter in the area than usual.
Scarlet mistletoe, which in the southern area often flowered about Christmas time, had already been seen flowering in the Catlins early this month, much earlier than usual, Mr Harris said.
University of Otago botanist Emeritus Prof Sir Alan Mark said heavier-than-usual flowering and seed production by beech trees posed the threat of a predator explosion, which the Department of Conservation was already working to prevent.
The changes in plant and insect behaviour reflected climate change, which would make it easier for some insect and other pests from abroad to establish themselves in this country, instead of being killed by winter frosts, he said.
