I’ve become increasingly fond of moths over the last few years, but seldom am I lucky enough to get a good look at one. The obvious reason being their nocturnal nature: the vast majority of species fly at night, diverse hordes of them taking to the air unseen whilst us day-dwellers are tucked up asleep. This is where moth trapping comes in. The general principle is quite simple: put out some sort of a light,* and wait for moths to be drawn to it like, er, moths to the flame, ready to be observed and identified.**
Whilst it may have become something of a cliché, many species of moth do indeed find light irresistible. This is probably because they are thought to navigate using the moon, and the trap’s light in effect creates a decoy moon which tricks the moths into flying towards it instead of the real thing. When the moon is particularly full or otherwise bright, you would therefore expect catches in light traps to be lower, and this is demonstrably the case: both cloud cover and moon phase influence the number of moths caught on any given night. Presumably when the real moon is easy to see, moths become harder to fool.
The design of the trap itself varies, but it is generally some sort of partially open box, stationed underneath a bulb or strip light, and lined inside with egg boxes which make a nice cosy place for the moths to crawl into after they’ve calmed down. What results is possibly the laziest form of wildlife recording: put the trap in your desired location, turn on the light, and go to bed, dreaming of what might come to be lurking in the trap’s depths by dawn. That’s how sensible people do it, anyway, though I have heard tell of hard-core moth-ers who stay up all night, eagerly poring over the trap and studying each individual as it blunders in. This strikes me as being a little like the children who can’t wait until Christmas morning to open their presents, and end up tearing the wrapping off before they’ve gone to bed on the 24th. In a way it does actually sound fun – being sensible is overrated, after all – but last weekend we elected for sleep.
For we had taken advantage of my newly employed status (at Reading University – like the ultimate human boomerang, I just keep coming back) to borrow a proper moth trap, two of them in fact, which we keenly hoped would be more successful than the sheet + desk lamp affair we’d rigged up for the Garden Bioblitz. And what we had forgotten to bargain for amidst all the excitement and anticipation of a moth night is that it is the morning after when the hard work really begins. I’ve been present at a number of trap openings in the past, but this was the first time I had set one myself rather than lurking about the periphery of another session. I am, therefore, an entirely amateur moth-er, and whilst I have a reasonable grasp of the major moth families and know a few of the commonest species, I wasn’t prepared for just how long it would take us to process our catch. The lazy naturalist might not be so well suited to moth-trapping after all.
Luckily moth identification is relatively familiar ground for birders, and the four of us who worked on identifying the specimens are all members of that tribe to varying degrees of experience and obsessiveness. Just as is the case for birds, most species of moth can be separated by colour, pattern, and shape, and there are many excellent field guides which illustrate these. Martin Townsend and Paul Waring’s guide to Britain’s 880+ larger moths, skilfully illustrated by Richard Lewington, is currently the most popular and is definitely my favourite of those I’ve flicked through.*** A partner volume, this time a guide to the micro-moths – of which there are even more! – was published last year, and has earned rave reviews.
And if you’re still not sure after consulting a book, the Internet is awash with friendly enthusiasts ready to welcome us newcomers to the Lepidoptera-loving fold by sharing their extensive knowledge of all things moth. Even after a day or so of poring over our specimens (admittedly with lengthy breaks for food, a nice walk on some chalk grassland, and another night’s sleep) with a copy of the aforementioned field guide to hand, we were still less than 100% sure what some of them were, and in some cases absolutely clueless. But with the help of expert opinion I think we have managed to put a name to everything that came a-visiting during last Saturday night. Those 25 species, listed below, represent but a small sample of the intricate beauty and astonishing diversity of moths, and I know I will be coming back time and time again for more. I suspect and hope the friends whose garden the traps were set in are now a little bit hooked as well.
Moths in no particular order, photos in order of appearance:
Light Emerald (1), Common Marbled Carpet, Marbled minor (agg.), Heart & Dart, Willow Beauty (2), Mottled Pug, Green Pug, Common Pug, Garden Carpet, Heart & Club, Lychnis (3, right), The Spectacle, The Uncertain, Shuttle-shaped Dart (3, left), Pale Mottled Willow, Mottled Rustic (4), Riband Wave, White-shouldered House Moth, Rustic Shoulder Knot, The Flame (5), Flame Shoulder, Dichrorampha alpinana, Crambus pascuella, Celypha lacunana, Eudonia mercurella.
Thanks to Becky Thomas at Reading University for lending the traps, and to friendly moth-ers Richard Comont and Andy Pay for their ID assistance.
*There is also the option of cooking up some ‘moth sugar’ and painting it on a fencepost. Most recipes I have seen contain beer, brown sugar and treacle, so I can see why moths would find it attractive – in fact, it sounds too good to waste on them!
** Although, come to think of it, an actual flame would not be a particularly effective way of catching identifiable specimens. Moth toast, anyone?
***It’s been high on my wish list for a while, though for some reason my family persist in skipping over it in favour of less esoteric gifts. For which I’m grateful, I am, but I really do want a copy!