Friday, 9 October 2015

Protective mimicry

It was definitely probably a hornet, possibly a giant hornet, possibly if the rumour-mill was worth listening to, even a giant Asian bee-killer hornet. And if it wasn’t the effect was the same, as I was both excited and worried. If you look up anything about hornets you will find that they are aggressive, dangerous, and eat all sorts of good things like bees, and bad things like wasps, and even doing that doesn’t improve their reputation.

I have to admit to having had some investment in this one actually being a hornet – I have been pointing out hornets to people for years, noting their generally placid behaviour, their brown and faded yellow stripes that make them look like tired old wasps, their aimless wandering about the place and their tendency to settle and appear to have to catch their breath. All of which are in fact characteristics of the hornet mimic hoverfly, which this was, as I discovered when it was pointed out to me that I ought to look it up. And thank goodness that it was not a specimen of the true hornet, which is aggressive, dangerous, as previously mentioned, as well as fast, noisy and which dresses in hazard warning tape. Hornet mimic hoverflies have evolved to look like hornets, to avoid being chased and eaten. They certainly have done well out of fooling me, even though I would not have chased or eaten them. But it’s certainly considerably more than one-nil to the hornet mimic hoverfly: indeed, a walkover, a whitewash, a rout. They’ve done well out of pretending to be hornets. And being a gentle soul I take my defeat manfully and praise my opponent. Protective mimicry is great, and clearly works. I admire it. I admit defeat.

But, if a handful of hornets arrived in my garden I would think very seriously about taking action, phone the person who deals with such things – the council I suppose, though a moment’s thought would tell me that the relevant department was probably privatised years ago, and its work is now done digitally with a three-month waiting list and payment required by some technology that hasn’t reached me yet. And I think I would be similarly disposed towards urgent action if half a dozen hornet mimic hoverflies started hovering over the patio. Their mimicry would not help them. The problem is that human evolution has moved so fast that it has left other bits of evolution far behind, specifically the retention of hornet-like coloration by the hornet mimic hoverfly. Hoverflies evolved taking benefit from a chance mutation that caused a similarity to hornets, but which unfortunately makes humans more likely to kill them, which we can now do with ease, theoretically; that is, we have the means, though not always success in deploying them.

An addition to the situation is the Asian hornet, now successfully ‘invading’ France, and threatening British shores with its reckless violence, voracious appetite and barbarian reputation, heavy baggage to add to that of any migrating species, which if it does any damage to any species already here is doomed to be termed ‘invasive’. 

Asian hornets may already be here. On 14 August 2015 the Central Somerset Gazette posted a story about Sally Bancroft, who owns Bancroft carpets we are told, and who spotted a wasp-like inspect on the balcony of her mother’s Glastonbury home. 

‘It flew into a cobweb, it was stuck,’ she said. ‘I couldn’t believe the size of it. It was as big as my husband’s thumb. It was about two inches long and its stinger was out, and it was about 5mm. When we Googled it, and from the description, it sounded like a Giant Asian Hornet. I don’t know if there have been any other sightings.”

The Central Somerset Gazette added ‘Mrs Bancroft stressed that she wasn’t a nature expert but it fitted the description perfectly. She said it had a yellow head and legs. Mrs Bancroft’s only regret is she didn’t manage to catch it as now she can’t get definitive proof if it was a Giant Asian Hornet, the world’s largest hornet, or not.’

Note that the Asian hornet has become the Giant Asian hornet. Mrs Bancroft’s curiosity is admirable, but a more likely scenario was that reported by the Daily Mail on 21 May 2014 - an Asian hornet 2 ½ inches long entered a kitchen in Staffordshire and was sprayed with fly-spray, expiring after ten minutes. No doubt the fears about potential invasions of Asian hornets, giant or otherwise – they eat 50 bees a day, according to ‘some experts’ cited by the Daily Mail 21 May 2014 – will have many good honest folk, and Daily Mail readers, reaching for the can of Raid when they see a hornet mimic hoverfly. What price protective evolution then?

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