Wasps major threat to monarch butterflies
Taranaki’s monarch butterfly population is being killed off by an explosion in the numbers of Asian paper wasps.
The region is not alone and nationally there’s a ‘‘huge shortage’’ of monarchs, which is believed to be primarily due to the wasp, Nelson commercial butterfly grower Ian Knight said.
‘‘They’re the biggest threat [to monarchs] at every stage of life, from egg and caterpillar to chrysalis and butterfly,’’ Knight said.
Jeff Wills, of Bio-Tech Pest Control, said he’d seen the wasp numbers explode in recent years, from only treating one nest seven years ago.
‘‘On Saturday, on behalf of someone else, I treated eight along one fence,’’ Wills said.
‘‘They are a big problem as far as I can see. In some situations they are totally decimating the butterflies.’’
Unlike common or German wasps, paper wasps only take live prey and do not respond to poison bait like Vespex.
Wills said one nest he exterminated recently had been built on a fence next
to a swan plant.
‘‘They didn’t even need to fly. They just walked along the fence straight into the plant and killed them all.
‘‘They get all of their protein from caterpillars. They will sting all of the caterpillars and cart them off for lunch.’’
Paper wasp nests must be killed individually and Wills said over-the-counter pesticides would do the trick and people didn’t need to hire an exterminator.
‘‘Any fly spray sprayed directly on them will kill them, they are extremely docile and you can get within 500mm.
‘‘After a quick spray they will normally hit the deck.’’
Wills encouraged anyone who had an Asian paper wasp nest on their property to kill them off.
‘‘Wipe them out before they wipe the monarchs out.’’
Paper wasps are different from common or German wasps, and can be identified by the long, dangling back legs that hang below them when they fly. German and common wasps tuck their legs up to fly.