By DANIEL JACKSON
Monarch butterflies are around in greater numbers this year, thanks to favourable weather and an unexplained reduction of one of its main predators.
The introduced butterflies have been under attack for the past 20 years by another introduced insect, the Asian paper wasp.
Landcare Research entomologist Dr Trevor Crosby said the monarchs were bouncing back this year because of good growing conditions for their main source of food, the swan plant, and a bad breeding season for the predatory Asian paper wasp.
Takapuna resident Bruce Daniell has the evidence of the population increase fluttering around his backyard, thanks to a bit of preparatory elbow work.
He made a special effort to grow swan plants in his garden and is reaping the rewards as the insects have started hatching from their chrysallises in the past few days. Hundreds more will hatch in the next few days.
Meanwhile Ministry of Agriculture and Forestry staff hope they have killed off another introduced insect after poisoning a red fire ant nest at Auckland Airport last week. A nest of the south American natives, which can give a sting similar to a wasp, was discovered near a container terminal by a gardener at the airport.
Pest exterminators and ministry experts moved quickly to destroy the nest, the first found in New Zealand.
MAF spokeswoman Amelia Pascoe said the ants were voracious predators and could have a devastating effect on New Zealand's biodiversity.
Staff have set traps in the area and organised a monitoring system in case the ants have spread further.
King of butterflies bounces back
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