Moths 3. Now really getting down to it.

MOTHS 3 : Now really getting down to it.

About ten years ago, after  a spell of illness , I was unable to get out and about much for a twelvemonth so I picked up the less mobility-demanding Moths hobby once more. I bought a Robinson trap which consists of a drum with a funnel at the entrance and a powerful 125Watt Mercury Vapour bulb fixed above. Moths are attracted to the Ultra Violet light emitted at night, and are directed by vanes around the bulb, down the funnel and into the trap, where they settle quietly in the nooks and crannies of the egg trays at the bottom of the holding drum. The funnel makes it easier for them to get in than to escape.

The bulb runs off either mains electricity or a generator, and because it gets hot, it needs a rain guard over the top to prevent it blowing up if it gets wet.

Robinson trap

With recovering mobility we now stray away from the garden and set up the trap in various suitable locations, mainly in East Cornwall, with permission from landowners or by invitation from people who are interested to find out what we catch. 

The conditions need to be favourable : overcast, mild, even muggy, with little moon,  and no wind. A little rain or drizzle doesn’t bother the moths but I find a heavy wet mist seems to disorientate them. They will approach the light and then veer away erratically.

 Low temperatures reduce the numbers, but any suitable night all through the year is trappable as different species emerge at different times of the year. Through the winter however, numbers are low, gradually increasing to a peak from mid June to later in August, before falling away again.

 

When trapping away from home we travel in the campervan and stay in it overnight near the trap. We leave the light on all night and at first light I go and switch off and cover the trap with a blanket so the moths stay quiet and dark. This may be around 4am in midsummer, so then I go back to bed for a while. Before breakfast we open up, identify the catch, count the number of each species, photo when necessary and release the moths before going home for breakfast. Hopefully it’s still cool enough before breakfast to keep the moths quiet.  Otherwise as they warm up they get very active and can explode out of the trap and away, as soon as you lift the blanket. And of course, the best ones are always the ones that get away!

A good night even these days, may produce perhaps 400 individuals of up to 100 species here in East Cornwall in a good site.  Although the numbers of individuals will vary from year to year, overall the numbers are largely down compared with the old mothing days with the local Field Club in the ‘80s. This is a contrast to trapping in areas of France where, when camping in the summer, even with a less powerful light in a different trap, we almost invariably get catches of this size.

Skinner Trap with Synergetic tube and the cart for carrying generator and the rest of the gear.

While the traps' design may vary they all have the same principal , although different lights may have a different Ultra Violet spectrum and attract different species. And some traps retain their catch better than others.

Even more portable: the Heath Trap

 The records are sent to our County Recorder, who will always try to identify a moth you are doubtful about and provided he agrees with your identification the records are sent both to the County Data-base and up the line to the National Data-base.

This season of course, so far the away nights to trap aren’t happening, so we are just putting the trap out at the bottom of the garden.

 

Visitors Welcome and Less Welcome 

 

The bright light invariable attracts other creatures, including curious occasional passers-by, lads coming home the worse for wear at turning-out time, police...these days I like the moral support of company.

Convivial company

 

 

 

 

One evening trapping at the edge of a wood, I was watching the trap for the odd crepuscular moth and because there wasn’t much action Tony was reading in the van. The hairs on the back of my neck started to rise as there were odd cracking noises coming from the wood, as if something was moving stealthily nearby. I discounted the cattle in the adjacent meadow. They’d have made more noise than that if they had got into the wood, but I thought deer would have made less noise. The sounds repeated every now and then and I went back to Tony saying “I think there’s someone in there”.

 He came out with me and soon the cracking noise happened again. Then Tony looked up and said “That tree’s moving!” And sure enough nearby, silhouetted against the twilight sky, we could see  the top of a tall tree quivering, and as we watched, the top 15 feet or more snapped off, keeled over and crashed into the neighbouring trees! If it had gone the other way it would have gone right down on the generator standing in the track near us ! There was no wind, and looking at it the next morning it was an apparently healthy oak. The cracking  sounds I had heard were the first signs of its stress, but why??

Certain species of Gum trees are known as ‘widow makers’ in Australia because of their propensity to shed limbs unexpectedly, killing people sleeping under them when ‘out bush’.

Hornet. This one is at its nest entrance in a bank.

The light in the trap will also attract other creatures. Sometimes night-flying hornets will come and bumble round the light, not aggressively but disorientated. Some will go and roost among the egg trays, so you have to be wary when handling them in the morning, but sometimes they come in large enough numbers to drive us into the van. 

One night we un-knowingly set up the trap near a wasps’ nest . The whole lot quickly emerged and filled the trap with confused wasps.We had to switch off and retire till the morning when we opened up and let the wasps go back home. The moth catch was  an abysmal 3, as the sheer number of wasps  must have deterred the moths. We found the same happened one night when there was a mass emergence of Daddy Long-legs. The next morning the trap was completely full of the crane flies and scarcely a moth! 

Midges are the worst mass visitors. In some damp places on a quiet muggy night huge clouds may form round the light. Those which don’t  drive you potty  with bites will nevertheless get in your eyes, your nose, your mouth.....

Great Green Bush Cricket also attracted on the dunes.

When trapping on the dunes in West Cornwall a couple of summers ago we had the unexpected visit of Glow Worms. The generator has a small green light shining when it’s running and we found 11 male Glow worms attending what they thought was the green glow of a female!

Down near the River Camel  one  summer evening , the trap was enveloped by a vast number of small black-winged Caddis flies, but by midnight they had disappeared as suddenly as they appeared, leaving numbers in the trap but only a minority of the vast numbers  originally flying around it or settling on the surrounding white sheet.

One rather upsetting ‘by’catch’  when trapping by the coast in Brittany, was to find in the morning huge numbers of Sand Hoppers, mostly unfortunately dead in the bottom of the trap. To get to the trap they had come up the beach, got over a 2ft high wall, across a stony track and then over 10 yards of grass and into the trap!

Cockchafers appear in May, often in large numbers.

 One of the Dung Beetles, the Common Sexton or 'Burying Beetle' frequently attracted to the light.

The 'Tanner' a long-horn beetle.

 Various sorts of beetles may  be in the trap in the morning, from small shiny black dung beetles to the big black or black and orange burying beetles, ‘long horn’ beetles and most dramatically in France last summer, two male stag beetles. Despite their dramatic appearance there was no evidence that they had neither attacked each other, nor the moth catch.

Male Stag Beetle. We saw them often at twilight in France last summer.

On an otherwise ‘good night’ as we stand around the trap to see what’s coming to the light, an otherwise lively attraction can stop dead for no apparent reason. No sudden fall in temperature, no sudden getting-up of wind, but looking up, there will be a bat or two, and an occasional moth wing may flutter down. Hunting bats have got onto the attraction and have come to feed on the moths. I suspect the moths sense the bats’ echo-location noises and clear off.

 But occasionally visitors inside the trap may cause havoc. Spiders will dismember the roosting moths, leaving wings as evidence. Rather to my surprise, hornets don’t seem to attack the moths, nor did the Toad that was squatting in the corner of the trap one morning when we were trapping in Brittany.