While it’s hard to describe an outbreak of heather beetle on your own ground as a good thing, the beetles that have destroyed an area of heather on the Chayne this year have served an important purpose by allowing me to study them at close hand. Readers of this blog will have watched the attack progress since the end of July, and I was oddly gratified to find that the adult beetles themselves hatched almost precisely as predicted last Thursday. Although it was a small trickle at first, by Saturday the ground was wriggling with beetles. As I tried to get close to them for a good look, I found that they were very shy indeed. The slightest vibration or sudden movement would make them fall straight off the heather shoots into the moss, and it was only with a surprising amount of careful stalking that I was able to get in amongst them.
Serious infestations of heather beetle can mean that there are more than 1,000 larvae per square metre, so while my outbreak was quite dramatic, it was nowhere near these almost biblical proportions. I watched the adult beetles working away at the heather leaves until the rain drove me in, but although I vowed to return with the camera on Sunday, work got in the way. On Monday the weather was terrible, and then yesterday I was in England, so this morning was the first opportunity I’ve had to get back up the hill with a camera.
The arrival of a sudden bitterly cold wind has turned much of the mellowing shades of autumn into the stark bleakness of winter over just a few hours. The change must have had an effect on the insect life, because despite searching for over half an hour this morning, I could not find a single heather beetle. Caterpillars, spiders and a single grasshopper all revealed themselves during the finger-tip search, but I was totally unable to clap my eyes on even one of the brutes that had been so gaily eating my heather on Saturday. It led me to think just how easy it is to suffer from terrible heather beetle damage without ever even seeing a beetle.
When I was down in the Peak District on Tuesday, I saw some pretty serious beetle damage on a moor near Buxton. Ninety percent of the heather on the 70Ha moor has been damaged in one way or another, but neither the keeper, the landowner or the ecologist I was meeting with had seen a single beetle. You would think that if your heather was being eaten alive by a swarm of beetles, you’d be able to spot the buggers responsible, but as I found this summer, the larvae are very well camouflaged and the beetles themselves are only really around in any great concentration for a few days of the year. The rest of the time, these insects are buried away deep in the sphagnum, invisible to the human eye.
The case in the Peak District is very worrying, particularly because outbreaks often have a habit of lasting around three years. The fact that this massive attack took place without any warning or precedent would suggest that it is not yet over, and it could be that recovery work will be hampered by further damage. The beetles will start to be inhibited by a lack of heather if they persist in a single area, but that is no consolation to the syndicate that has worked so hard to turn rank moorland into a productive moor. The best strategy we can have in these situations is to put the pieces back together quickly and stay positive. As is the maddening nature of these things, it is impossible to plan for the beetle’s next move –