Tag Archives: Asilus crabroniformis

The Jones index of implied menace

US entomologist Justin Schmidt has carved out a place in entomological history by putting together the Schmidt pain index to measure the intensity of insect stings. These range from a score of 1 the tickle of sweat bees (Halictus species etc) to 4 the kind of pain that makes you lie down and scream (bullet ant, Paraponera clavata). The pain index is referenced throughout the internet, but this is the Natural History Museum’s take on it.

Not wanting to be outdone I’ve decided to launch the

This is the opposite of a pain index, because none of the insects has a sting. They just look threatening.

It seems obvious now, that stinging or poisonous models might be copied by harmless mimics, to trick potential predators into thinking that they were painfully dangerous, but it wasn’t until naturalist and explorer Henry Walter Bates formalized it in 1861, that the idea gained widespread understanding. It is now known the biological world over as Batesian mimicry.

The Jones index of implied menace is an irreverent unpicking of Bates’s mimicry, aligned on a scale from Woah! to Oh how cute. At menace level 4 even the hardened entomologist might take a step back and stand cautiously for a moment or two as they size up the target insect. Menace level 1 just brings a smile to your face and the thought: “What pretty colours”. Even more so than Schmidt’s pain scale, my index is subjective in the extreme. But it works for me.

4. Hornet robberfly, Asilus crabroniformis.

Damn this thing looks pure evil.

 

Arguably Britain’s most striking fly, the hornet-mimicking Asilus crabroniformis. Taken from its well-deserved place on the frontispiece in Colyer & Hammond’s (1951) Flies of the British Isles.

3. Hornet moth, Sesia apiformis.

A moth? Really? Are you sure?

The hornet moth, Sesia apiformis, is one of the clearwings, named for their narrow, transparent, unscaled and unpatterned wings which make them not at all moth-like, but very wasp-like, very wasp-like indeed.

2. Phantom hoverfly, Doros profuges.

Sleek, but with that sinister-looking narrow waist and menacingly darkened wing edges….

The ‘phantom’ hoverfly, Doros profuges. I’ve filched this as a screenshot from the excellent diptera.info website; I hope they don’t mind.

1. Ant beetle, Anthicus floralis.

Looks a bit like an ant — if you squint.

Anthicus floralis does look remarkably ant-like when it runs about at top speed on the ground. But it’s hardly a thing of nightmares.

Like Schmidt, I’m prepared to allow some latitude, breaking out from the 4-point scale, when necessary. The brightly coloured craneflies, Ctenophora, look creepy as well as being threateningly coloured, enough to score 3.5 maybe.

For some people the creepy long legs do it, for others it’s the intimidating upturned spike of a tail. But, like all craneflies, a female Ctenophora pectinicornis is completely harmless.

Most hoverflies would rank 1, although I might make an exception for Volucella zonaria, and give it a 3, if only because of its menacing size.

Even dead in the hand it looks unnerving — Britain’s largest hoverfly, Volucella zonaria.

On the other hand conopids, which are visually superb wasp mimics actually look too cuddly, so only get 2, except for Sicus ferrugineus which, with its curled can-opener tail, looks a very sinister 2.7.

The brightly coloured wasp longhorn, Rutpela maculata, scores 2 when it walks, but a waspish 3 when it flies.

The wasp longhorn, Rutpela (Strangalia) maculata is a frequent flower visitor and does that hawking bobbing flight so characteristic of wasps.

So next time you stare in wide-eyed startlement at some large buzzing bug, beetle or fly, which you first thought was a wasp, but now realize is a mimic, remember to take a moment during your stand-down relaxation to ask yourself the question: “Yes, but what Jones score did it elicit?”