In an article that first appeared in Butterfly, a magazine exclusively for members of Butterfly Conservation, in Autumn 2020, Peter Marren traces the evolution of mothing, from its early experimental days to today's advanced techniques.
Around 330 years ago, certain well-off people in the south of England discovered butterflies and moths. By 'discovered', I mean that they were the first to take a serious interest in 'papilios', and began to give them individual names. Butterflies were easy enough to encounter. You simply chased them with a home-made net. Moths, being mostly nocturnal, needed more fieldcraft. Pioneer moth hunters had no light traps and even their lamps were weak. Yet most of our larger moths were known by the year 1800. How did they manage it?
Searching for caterpillars
One method was to search for caterpillars. Eleanor Glanville, of Glanville Fritillary fame, used a stick to 'beat' the bushes, so that the caterpillars dropped on to a sheet that she had spread out. She would then rear them in her conservatory. It follows that many moths were better known as larvae than as adult moths, hence such names as kittens, tussocks, thorns and geometers, all named after the caterpillars.
Another way of finding certain moths was 'assembling'. From the start. it was known that a virgin female moth would attract males from far around. In the National Gallery there is a picture by Melchior d'Hondecoater, active around 1660-90, showing male Emperor moths flying in to mate with a single female Emperor. Around the same time, the naturalist John Ray noted how a newly emerged Peppered Moth quickly attracted would-be suitors in his garden in Essex.
Attracting moths to bait
Searching for caterpillars and rearing them up was time-consuming. But in 1842, a method of attracting moths to bait was heralded as a revolution. Edward Doubleday, the son of a grocer, had noticed how moths were attracted to empty sugar barrels in the yard. He experimented with sugary baits painted on to walls and trees, and found that the best results came when fermenting fruit and a shot of old rum was added to the treacle. And so, for the rest of the century, collectors would set forth with a tin of sticky 'sugar' and a paintbrush, returning later to check the moths by the light of a lantern.
The technology of light improved during the 19th century. Oil-powered hurricane lamps cast a much more powerful and controllable beam than candles did. Later on, still more powerful incandescent lamps were in use. Entomological suppliers turned out custom-designed lamps and magic lanterns. One simple but effective way of using them was to shine them on to a whitewashed wall or a sheet suspended from the clothes line.
The moth trap
The next stage in the evolution of mothing was the moth trap. Various forms of light trap were available from the 1930s but the best was the Robinson trap. The awesome light power of this trap was provided by a mercury-vapour bulb, which cast beams of ultra-violet light visible to moths but not to humans. The moths flutter around the bulb until they hit a metal pane, after which they plop down a funnel into the container, where the thoughtful owner will have provided cardboard egg boxes for the moths to shelter from the glare.
Robinson traps were powered by electricity. And so, unlike Tilly lamps, they were anchored to your house. In time, weaker but cheaper traps that could be run from a battery became available, including the well-known Heath trap and the later Skinner trap.
Sugaring trees
In the meantime, 'sugaring' trees with your mixture of molasses, rotten bananas and rum was superseded by the use of wine-ropes. This method, hastened by the availability of cheap red wine, involved dipping absorbent cord or even rags into the mixture and then hanging them from a tree. Like sugaring, the technique attracts moths that tend to ignore light, such as the various Crimson and Copper Underwings. It's also arguably a more exciting and natural way of spotting moths than peering into the depths of a trap.
Sallowing
There are still other ways of finding moths that I have been introduced to from time to time. One is 'sallowing', which you do early in the year when nectar-rich sallow is in flower but not much else. Moths imbibing the presumably semi-fermented sugar from sallow catkins seem to become temporarily incapable of flying far. You simply spread a sheet under the boughs, beat them with a stick and watch the moths fall like ripe fruit. Or, more sportingly, you can clamber up the tree and shake off moths by bouncing up and down.
Dusking
Another way is 'dusking'. You choose a warm, still evening, and wander, net in hand, through long grass and vegetation, kicking the grass and poking likely bushes with a stick. Dusking is effective for small, crepuscular moths such as micros and geometers. It's kind of walking-with-moths and is unusual in natural history in that, instead of keeping quiet, you make a commotion.
The modern way of mothing
Nowadays, of course, the routine way of recording moths is to sit around the lamp at night, eyes averted from its glare, or by inspecting the trap in the morning. The residing expert intones the wonderful names. Someone else writes them down. Records are made. And that done, the moths are returned to the bushes to continue their secret lives.
We have chased after moths in Britain for as long as science has existed. And there is something about this pursuit that is hard to put into words - a sense of excitement, of communication with the wild, and the beauty of the moths themselves. It is fun and interesting, and it makes us happy. Long live the dark arts of beating, assembling, sallowing and sugaring.
Peter Marren is an acclaimed naturalist and the author of many books on the natural world.
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