Te Radar's Rant: Wasps up?

Wasps are having calamitous effects on our South Island ecosystems. Photo / Supplied

Entertainment: The sandwich-bothering, sweet drink-sucking wasp is now also a bottom feeder. The little blighters must be stopped.

I'd always imagined wasps as suavely brutish vegetarians. Having never considered the prospect that they might be carnivorous, it's fair to say I was disconcerted to find they are partial to the taste of flesh.

When I discovered that the antics of the predacious invaders Vespula Germanica, (the German wasp), and the superbly named Vespula vulgaris, (more humbly known as the common wasp), threaten native birds like the gregarious kaka I was mortified.

I pictured swarms of these black and yellow bullies stooging through the bush killing and devouring our parrots in a flurry of tiny nibbles. If that's the case, I thought, I am never going to the South Island again. It sounds dangerous, and ghoulish.

But no. This is not the case. Well, not exactly. While these wasps do devour other insects, and have been witnessed killing newly hatched birds, it's the sheer number of them that's the true horror.

In parts of this fair country there can be as many as 350 wasps per square metre, all of them busy going about the tasks that wasps have of a day, namely finding things to eat in order to create more wasps.

In some areas the collective weight of the wasps is greater than that of all of the birds although the mind boggles slightly at how you get all those wasps and birds to sit quietly on the scales to find this out.

Little wonder Professor Phil Lester from Victoria University's School of Biological Sciences has declared that the summer densities of these wasps need to be reduced by a staggering 80-90%. This would reduce their numbers to a mere 35 wasps per square meter. To be honest this still seems to be about 34 wasps too many.

Their plague-like numbers are bad enough, and a danger to anyone who encounters them, but their real threat lies in their passion for honeydew.

This delightfully named substance is the sweetly sticky excretion of tiny scale insects. These creatures dwell on beech trees, and are described in scientific writings as being little more than a mouth and a very long anal tube, from which honeydew is forcefully expelled to the gastronomical delight of birds, bugs, bats and fungi.

Unfortunately the wasps have discovered that they can glean more dew if they nibble the end off the scale insect's digestive tube, which is not all pleasant for the insect, which promptly dies. The wasps are, quite literally, bottom feeders.

The resulting honeydew shortage is a catastrophe for those forest dwellers that rely on it. Widespread malnutrition ensues. Clearly something has to be done.

Fortunately a workshop was recently held at Victoria University to look at the problems caused by this terrible twosome of wasps. Unfortunately, it was stated, that there doesn't appear to be a solution at this point.

But they did take the proactive step of forming a Wasp Tactical Group. The press release trumpeting the formation of the group failed to mention what tactics these tacticians would employ.

Perhaps they will take a leaf out of Scotland's anti-wasp campaigns, where until the 1950s one region there had a competition for children to see who could catch the most wasp queens, as if life for kids in 1950s Scotland wasn't difficult enough. There was a cup and a small bounty as prizes.

I can't imagine sending hordes of children clad in sturdy overalls, balaclavas, gloves and armed with fly-swatters into Te Waipounamu's beech forests will be an entirely acceptable approach to wasp eradication, but it might just be all we have. Let's hope the wasps don't develop a taste for our young.

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