I have been running a moth trap this year in our garden in Dulwich Village. A moth trap is basically a box with a bright light on top and a funnel arrangement so that when moths fly in, they cannot easily fly out again. You put egg boxes inside for them to sit on, then in the morning, you open up the trap to see what’s inside, and let them go.
It’s a bit like Christmas morning, as if Santa mainly brought moths (and assorted caddisflies, leafhoppers, midges, daddy-long-legs, beetles and wasps). I am not the only one who takes an interest in what’s in the trap. I quickly learned to keep the cat inside because he enjoyed chasing and eating the moths. In the late summer I started having problems with wasps raiding the trap, and there is a friendly but irritating Robin who now hangs around and grabs moths when my back is turned.
The most striking thing, compared to, say, birdwatching, is the sheer variety. This year I’ve run the trap 71 times so far and caught just over 300 species. At the peak, in July and August, I was regularly catching over 70 species and well over 200 individual moths. This meant it took over two hours to empty the trap and photograph anything that looked interesting, and then another few hours identifying anything new and updating my records. The biggest one-night total was 375 moths, although 230 of them were of just 3 species.
They have terrific names: Toadflax Brocade, Seraphim, Pebble Prominent, Knot-grass, Maiden’s Blush, Phoenix, Vestal, Blood-vein, Smoky Wainscot, Rusty-dot Pearl, Clouded Drab, Shuttle-shaped Dart, August Thorn, Yellow-barred Brindle.
They come in all shapes and sizes; the smallest species I have managed to identify was probably Ectoedemia decentella, about 3.5mm long whose larvae form mines in sycamore seeds. The biggest was Poplar Hawkmoth with an 8cm wingspan. Some are camouflaged to look like deadwood, leaves or lichen and a surprising number are camouflaged to look like bird droppings. Although most of them are various patterns of brown and grey, some are more colourful like the Brimstone Moth (bright yellow), the White Ermine (which is white with black spots) or the Small Emerald.
The moths fill a remarkable range of niches as caterpillars; they eat the leaves of native trees and flowers, or garden plants like azaleas and Leylandii, or grass, lichen or leaf litter. Many of the smaller ones form mines inside leaves and there are species that live in bird’s nests or in the nests of bees and wasps. Some even live underwater, as caterpillars, feeding on pondweed. Identifying them is much easier than it used to be. There are now several excellent field guides, as well as lots of information and photographs online, and moths groups on Facebook where you can ask for ID help. In particular, micro moths, which are some families of mainly smaller species, are much more accessible for the beginner than they used to be. They can still be very challenging but with care and patience (and a macro lens for your camera) you can puzzle most of them out.
And at the end of the year, when I submit my records to the County Moth Recorder, I can feel I’m making a small contribution to science.