Aliens invade our gardens

By SUZANNE McFADDEN

The good old praying mantis is being run out of its backyard by its South African cousin.

The assertive South African mantid, which arrived uninvited about a decade ago, is taking over the territory of the New Zealand species.

It is the time of year when gardens are brimming with teenage mantids, otherwise known as nymphs.

But most of the little creatures you will see are foreigners.

Graeme Ramsay, a retired expert in praying mantises, fears the home-grown variety will become a rare breed in the not-too-distant future.

"I'm sure the New Zealand one will survive, but in very low numbers," he said.

The South African species has a distinct advantage over its Kiwi rival - it produces up to four times as many babies.

Around 70 eggs hatch from a New Zealand mantid's egg capsule, or ootheca, over two or three days.

"If a hungry spider waits, he can get a decent meal as they hatch, and eat the whole lot," Mr Ramsay said.

But up to 300 tiny, brown nymphs are born from a single egg-case of the South African mantid, giving the species a much better chance of survival.

The South African mantids, which sometimes have a straw-brown colouring, are more vicious than their cousins.

It is the South African female that regularly bites the male's head off after mating.

The warm, wet summer has made for a bumper crop of backyard bugs this season.

An entomologist at Landcare, Robert Hoare, said the recurrent rain of the past few weeks would not dampen the insect population.

"The insects are fairly well adapted to New Zealand's changeable weather. They've survived here for millions of years, so it doesn't make a great deal of difference," he said.

At this stage of summer, Auckland gardens are home to honeybees, monarch butterflies, stick insects and wetas in woodpiles.

The latest arrivals are new species of moths, which have been blown in from across the Tasman.

One Australian newcomer has brought potentially good news - its caterpillars thrive on the rampant jasmine creeper.