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When the hunter becomes the hunted

On 21st June 2010 I drove for 10 hours from home to get to Ullapool; the start of an 11-day entomological survey campaign in the west of Scotland. My survey site on 22nd was Rhidorroch Woods SSSI which turned out to be a couple of hours drive on dirt tracks up an increasingly beautiful glen. The weather was superb – a rare treat in NW Scotland – and I couldn’t wait to get into the field.

Rhidorroch Woods SSSI

This isolated veteran pine, above the modern-day treeline, was the best tree I found. Scarred by lightning strikes and ripped by the weight of winter snow, but still living, it was a magnet for saproxylic beetles.

On a fine, sunny day in Scotland, when big beetles like clicks, chafers and longhorns are buzzing past on the wing, there is no better place to be. As long as you’ve got a midge net (and are prepared to abandon all personal dignity and actually wear it)!

Undignified headgear

You also need to keep one hand free for swatting horseflies. And a little time is required each evening for tweezering off all the ticks!

It pretty much goes without saying, but the warning colours of this Bee Beetle Trichius fasciatus (a chafer) failed to frighten me. Very few of these Batesian mimics seem to be good enough at mimicry to fool the human eye.

Bee Beetle Trichius fasciatus

But, as I was investigating the hollow interior of a decaying birch, a bumblebee started harassing me at close quarters. I immediately backed off and legged it away for about 20 metres, reckoning I must have disturbed a nest. As soon as I stopped, I realised it was still buzzing round within a few inches of me. I carry an adrenaline injector with me at all times in case of bee stings: I’ve had a couple of bad allergic reactions in the past. But, even so, getting stung in such a remote spot could be difficult. I legged it back to the birch tree to grab my net, still with the bumblebee in pursuit, and netted it. Safe. Phew!!!

It was only then that I realised it wasn’t a bumblebee! The size, shape, flight and especially the buzzing tone were all spot on and had me completely fooled. But this was a fly, and like nothing I’d seen before. Much later, with help from Dave Gibbs and Andy Grayson I was able to identify it as Cephenemyia auribarbis.

Cephenemyia auribarbis

Cephenemyia auribarbis is a bot-fly (family Oestridae) and it was not looking to bite me or sting me but to lay eggs on me, so that its larvae could develop in either my nostrils, mouth or throat: a truly horrifying prospect! It should have been chasing after Red Deer, the usual host.


These observations were made during SSSI condition monitoring work for Scottish Natural Heritage.

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