Christchurch’s hot summer could be attracting the ‘ballerina’ of bugs

Two years ago, Jude Nuttridge noticed one “cute looking” moth-like bug on her window. Now her garden is full of the little critters eating up her plants.

Gardens across Christchurch are riddled with passionvine​ hoppers – a kind of insect that resembles a moth.

The hopper became established in New Zealand in the 1870s, but has only recently been noticed in such large numbers this far south – the hot summer being a factor in its shift.

Manaaki Whenua – Landcare Research, which specialises in all things bugs, has recently been inundated with queries from the public about the little garden monster.

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Nuttridge she had killed hundreds, if not thousands, of the insects over the past two months.

“I sprayed them again only yesterday, and they are back in the hundreds. They just come in like a cloud.”

Nuttrudge lives in Somerfield and said her neighbours have had the same issue. The bugs were eating into her flowers and vegetables, killing some plants completely.

“I put a picture of one on Facebook and heaps of people came back with the same issue. They are everywhere.”

Manaaki Whenua entomologist Dr Robert Hoare said climate change may be contributing to the population spike.

“One possible reason for more hoppers being seen further south this year is a gradual range expansion, which may be aided to an unknowable extent by climate change,” he said.

“It is common that when a species first moves into a new area it has a population explosion, since it takes a while for predators and parasites to catch up.”

There seemed to be fewer hoppers than usual in Auckland this year, but the number was starting to build up now – perhaps delayed by wild weather.

Hoare said the only way to eradicate or keep numbers down would be to introduce the Australian Epipyropid moth, which feeds on hoppers.

“There are no signs of it abating.”

Hoppers would go anywhere that mimicked the Australian climate, Hoare said.

The bug was said to walk like a ballerina. Juveniles had clear wings, while adult hoppers resembled moths.

Like all plant hoppers, they sucked plant sap, leaving behind a honeydew secretion gathered by bees.

Honey farmers needed to be aware of the bug, as it could taint their supplies.

In 2008, three people from one family arrived at a rural hospital in Waikato with vomiting and headaches after eating tainted honeycomb, the New Zealand Medical Journal reported.

Hoare said the hopper was not usually toxic, unless it had been feeding on the likes of tutin plants, which were poisonous.

The passionvine hopper is a seasonal bug that peaks from December to March.

Increased numbers have also been reported on the West Coast this summer, where the temperature had been hotter than usual.