MOTH TRAPPING
Moths are so often -- too often -- considered to be the downside of butterflies. Butterflies are colourful, popular and attractive whilst moths are so often regarded as creatures of the night, those drab clothes-eating annoyances that flutter in your face when you are in bed on a summer night with the windows open.
Yes, they do fly at night, and are usually subtly coloured, but many species fly by day, are colourful and pretty. A very few small moths do eat clothes, but more eat old dusty decaying corpses so are some of nature’s recyclers. And yes, attracted by the bedroom light, they will come in, but sadly, far fewer these days as moths, like so much of our wildlife, are now in sad decline.
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| Not all moths are drab! This is a Garden Tiger. |
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| Well-named Rosy Footman |
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| This lovely Blood-vein can be seen by day as well as being attracted to light. |
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| Subtle colouring but still attractive: a Brindled Beauty. |
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| A Mocha : what a pattern! |
Trapping: When?
Moths can be trapped at any time of the year, but the low numbers in winter gradually build up in the spring, to reach peak numbers of both species and number of individuals, in July and August, then tailing off with the autumn fliers.
Trapping: How?
The most productive way of trapping is to make use of the little-understood fact that many (but not all) kinds of moths are attracted to light, so a trap consists of a light above a funnel which directs the moths down into a roomy container with egg boxes for them to creep away and hide and rest until they are released the next morning after they have been identified.
There are many kinds of trap. Various designs of traps and lights are available ready-made or the necessary components are readily available from specialist suppliers or can be made by anyone handy with carpentry and electrics although of course any doubt about things electrical should be put in the hands of an electrician.
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| Heath trap. Advantages are that it is collapsible, highly portable and runs off a battery powering a low wattage Actinic light (this is the blue light you see in shops' 'Insect Zappers') Like the Mercury Vapour lamp in the Robinson, it emits Ultra Violet light rays which are seen by moths. |
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| Skinner Trap. This again is collapsible and portable, with a battery powering in this case, a 14Watt Synergetic tube. This has a different spectrum of Ultra Violet light and attracts well. The design of the Skinner does not retain moths quite as efficiently as a Robinson trap. Nevertheless when we use it in France where moths are still far more abundant than in Britain, we can catch well over 500 moths overnight. Quite enough to sort through next morning! |
‘Moth-ers ‘ have their own favourite designs and lighting systems and there are all sorts of ingenious systems set up and with Facebook pages to cater for every aspect of catching moths.
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| This home-made contraption, using a flat-collapsible laundry bag , with a little tweaking, ran well! |
Trapping: Where?
Traps can be set up permanently in one’s own garden, (with due regard for avoiding bothering neighbours with a powerful light) but many ‘moth-ers’ travel to various habitats such as woodland, moorland, old meadows, areas of scrub. Experience guides the siting, but shelter, and avoidance of competing light need to be considered.
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| This Skinner trap is sited in the shelter of a hedge but also attracts moths from the hay meadow. |
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| Robinson Trap with a Synergetic tube running in woodland. |
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| Skinner Trap on the coast, north-west Wales. A specialist site but maybe attracting a migratory species. |
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| A specialist site, a disused section of a cemetery, managed for wildlife. Children walking through on their way to school were fascinated to see the moths caught here. |
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| The trap here was to attract specialist moths whose caterpillars feed on pond-side emergent plants. The downside of these damp areas are the vast numbers of biting midges which are also attracted to the light! |
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| Robinson trap with generator, run on Bodmin Moor, looking for moorland species. On this occasion a very strong wind got up and we had a minimal catch.When the trap is on the ground we put it on a sheet as it is easier to see the moths which are attracted to the light but quite content to roost on the ground nearby. |
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| Normally a good site, on this particular night a very wet mist came down and although the moths were attracted to the light as they flew nearer, they swerved away and avoided it. I wonder if the droplets of water in the air were defracting the light and disorientating them. |
Trapping: Going back to When?
The time of year has already been referred to. Within that, the best, most productive conditions are overcast, mild, little moon, no wind. A little drizzle or light rain doesn’t seem to bother them; they will shelter from sharp showers and then re-emerge. I have found a really wet mist seems to disorientate them. They will fly but often seem to either miss, or avoid, the light. Full moon is said to compete and deter them but nature will break the rules as on occasions I have trapped on a full moon, with good catches. If bats appear, no doubt attracted by the moths, or if you have set the trap up near a roost, they quickly home in on a handy source of prey and the moths quickly detect the bats’ echo-sounding and disappear.
It's best to choose a site with little or no competing light.
It is considered that it is bad practice to trap consistently, night after night, at the same site as the trap is bound to cause disruption to the moths’ feeding and breeding. A frequency of every third night or even less often, is advised.
Trapping: Why?
At a purely personal level, trapping appeals to the interest and curiosity of the 'moth-er', and all agree there is a sense of excitement every time the trap is opened as you never know what will be there. ‘Christmas every time!’ is the by-word!
Trapping is the main method of accumulating a substantial number of records showing diversity of species, their abundance and distribution and trends will show up over the years.
Beyond that, and more importantly is the value of every record which gives
the species, the number of individuals of that species,
where it was trapped,
when, and
by whom.
These records should be sent to the County Recorder, who will verify, validate the record and send it to the National Data-base. The records are evaluated, analyzed and provide information on distribution and population trends to inform conservation on a local and national level.
Within the past few years, the many hundreds of thousands of
records of the larger moths throughout the whole country have been put into an
Atlas: "An Atlas of Britain & Ireland's Larger Moths", published last year and an invaluable guide to the status past and present of species and their distribution.
Identification
When in doubt the standard book is " A Field Guide to the Moths of Great Britain & Ireland" by Waring & Townsend.
If the small 'Micro Moths are a challenge the book to go to is "A Field Guide to the Micro Moths of Great Britain & Ireland" by Sterling & Parsons.
Both of these handbooks are beautifully illustrated by Richard Lewington.
A photographic guide is "British Moths & Butterflies" by Chris Manley. This edition has been followed by a second which omits the butterflies but has more moths described with more but smaller photographs.
A good photograph with if possible something to show the size, can help when referring to someone more experienced for help with identification. The County Recorder will usually help. You can’t beat going out on a trapping evening with a group to get help and useful tips.
When opening the trap in the morning it helps to keep it out of the sun and to open up early while the moths are still sleepy from their ‘night in’. When they warm up they are off, and there is nothing more discouraging than to see your precious catch erupt out of the trap as you open up next day!
I will discuss other methods of catching moths and their other life-stages in a future blog.
Blogs I follow:
www..northcornwallnaturalist.blogspot.com
www.musingsfromhigherdowngateandelsewhere.blogspot.com
www.downgatebatman.blogspot.com
Another interesting post, Mary.
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