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Overwintering Wasp Explosion

Landcare Research ecologist Richard Harris has found that German wasps can successfully overwinter, resulting in a population explosion.

From studying wasps over two seasons he found that while the incidence of overwintering was low, those colonies that didn't die out in winter displayed exponential growth patterns, reaching sizes over 90 times that of a single-season nest. The mild winter experienced this year could result in a greater number of surviving nests than normal.

Harris says not that much is known about overwintering in wasps, though it is thought that surviving nests contribute to the population growth. Wasps normally die out and queens hibernate, but overwintering nests produce multiple queens which expand rapidly.

"Some of the wasp nests were up to two metres at the end of the season and I counted 700 wasps entering a nest in one minute."