Did you know not all wasps are bad? Rakinui do now, thanks to a very interesting talk by Scott who had us all enthralled by the behaviour of a special parasitic wasp. The following articles clearly show how much the students learnt.

NOT ALL WASPS ARE BAD           

by Caitlin R and Nydia  (Y5)

Believe it or not, not all wasps are bad.

According to NZ scientists, some species even helped the environment. In 1996 a new pest was discovered in New Zealand in the North island. It was called a clover root weevil and it ate clover.

At that point in time, the clover plant was very important to agriculture. They had no idea how it got to NZ but they found some trace and think the weevil came on used cars from Japan.

By the time they discovered it, it had already spread to an alarming amount of 2 to 3,ooo per square metre.

By 2006 they had found a solution to this problem.

A PARASITIC WASP! Who would think! This species came from Ireland then got tested in England. Then they brought it to New Zealand.

The wasp creeps up behind the weevil and with its antennae it taps the weevil on the back. The weevil does not run away for it believes if it stays still the predator will think it is dead.

But this wasp is way smarter than the weevil. If it was dead the wasp will taste this and go away.

If it’s alive, it will put an egg in the weevil with a bit of venom to shut down the immune system. Over that period of time, the egg will grow in the weevil, feeding on the weevil's blood’s nutrients. When it is ready it will pop out of the weevil. The weevil will live 1 to 2 days after that.

If another wasp comes and plants it’s egg in the same weevil, it will not survive but the first one will. The Parasitic wasp has up to 120 eggs. The wasp will not get rid of all clover root weevils but does reduce the damage they cause. 

Why not all wasps are bad!        by Caitlin T  (Y5)

Like it or not, not all wasps are bad and I am going to give you the reason why.

In 1996 scientists found a bug called a clover root weevil.

A clover root weevil is a small bug that gnaws at the roots of clover which is a problem for farmers and their paddocks. The clover in the farmers paddocks helps fix nitrogen and it helps animals grow faster. But with these little bugs eating it, the root does not let the clover grow.

Without the clover it means farmers have to spray the gardens with some special spray which is not good for the animals. So scientists went round the world and finally found a solution, a species of parasitic wasp!

They brought it to New Zealand and it worked. This is how this clever wasp does it. They creep up behind the weevil and tap the weevil’s bottom with their antennae.

Then if it tastes nice it will turn itself around and inject eggs into it. The egg will shut off the weevils immune system then it will grow inside the weevil.

When it is ready it bursts out the back end. Then after a few days the weevil dies and then the wasp does what it’s parents did and finds a weevil and injects its eggs into it.

So that is the life cycle of this wasp. This wasp will not kill all of them but it will reduce the numbers of Clover Root Weevil. Also a fun fact, these wasps are only female! 

Article by Arabella  (Y6)

Last week, an entomologist came into Raupo to talk about insects and pests. An entomologist is a person who studies insects and bugs. He talked to us about a pest named the Clover Root Weevil. He told us that clovers are like air filters and cleanse the air of nitrogen. The weevil was destroying the clover roots, which do all the work for the farmers. New Zealand relies on farming for nearly everything. Mostly all of New Zealand’s money comes from pasture and farming. There were so many, that he could pick out a few thousand in about 5 square metres. It was becoming a big problem.

Finally, scientists decided to use a natural repellent that they found in Ireland. When they took it back to New Zealand, it had gone through multiple tests and a total of 10 years of quarantine before it was released into NZ. It has no common name, but is a parasitic wasp. More and more weevils were dying and eventually only a small number were being detected.

First, the wasp sneaks up on the weevil and tastes it with its long feelers. This is how they know if the weevil is dead or not so they can lay their egg in it. They insert the egg into the weevil, and then leave. The egg grows into a larva and starts sucking the nutrients out of the weevil, slowly killing it. When it grows fully, the weevil is probably dead, and the wasp repeats the cycle again.