Musk beetle

Pete and I actually managed a morning walk round Holme Fen before the day's torrential rain arrived! When we set out, all the vegetation was very damp from yesterday's storms, but the sun soon came out, making it quite warm and humid. The flowers at Holme Fen are at their best in August - a riotous mix of purple loosestrife, yellow loosestrife, hemp-nettle, greater bird's-foot-trefoil, wild angelica, hemp agrimony and hawkweed.

For once there were plenty of insects too - not only butterflies and dragonflies but metallic red and green leaf-beetles on the hemp nettle, a lesser stag beetle, iridescent blue sawflies and a good range of hoverflies. I could have blipped a number of them, but they were all outdone by this magnificent musk beetle Aromia moschata, busy feeding on the wild angelica, surrounded by the ubiquitous orange soldier beetles.

This species is totally unmistakeable. It's a huge (3cm or more) metallic greenish beetle with a purplish-copper iridescence with extremely long antennae. It's considered to be nationally scarce, but is not infrequent in the river valleys and fens of Cambridgeshire, though it's rarely seen. The larvae spend several years inside willows, especially pollarded ones, living on a diet of wood, before the adults emerge in July and August.

It gets its name from the sweet musky odour it emits, and is also one of the few beetles to make an audible noise. We once reared some from a piece of felled willow and they made surprisingly interesting pets, feeding avidly on sugar water.We eventually released them onto the willow in our garden but I'm not sure whether they ever established - we've certainly never seen them since.