Posted by: lensweb | November 7, 2015

Mothwork Night at Trent Lock

Mothwork Night at Trent Lock

Unlike domestic household bulbs, which give off tungsten light highly visible to the human eye, moth trap lamps emit a much wider range of light frequencies including those below the blue end of the spectrum in the ultraviolet (UV) range. It is the ultraviolet and lower frequencies of the white light band, which are most attractive to moths.

Although we are now past the last date for sensible moth trapping last night we went to the Canal and River Trust’s Trent Lock Drop In Centre to have a go. The sun set at 4.25pm taking us by surprise. It was very dark for setting up, but we had a source of electricity and light from the Drop In Centre. We ran Skinner design moth traps which consist of a wooden box with a central wooden crossbar housing a bulb holder and rain guard. Two large, angled pieces of clear Perspex have dual purposes, deflecting moths downwards, and allowing easy visual inspection to find moths which settle into the empty egg boxes which are placed in the box. We used two different light sources, a 125W mercury vapour (MV) lamp which is very bright and will usually attract more moths and the much duller Actinic which is preferable if you want your nocturnal activities to remain low-key. The two different light sources can attract different moth species.

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It had rained all day but the weather forecast was hopeful and  and we had high hopes of seeing a good variety of moths. We placed the Actinic trap next to the Erewash Canal towpath outside the Drop In Centre and the MV trap in a fenced off overgrown meadow. We relaxed in the chairs of the heated Drop In Centre and made ourselves a cup of coffee

It was a very dark but warm evening (13.5C) and we soon had our first few moths, a lovely feathered thorn and some light brown apple moths. Walkers and cyclists stopped to have a look and chat. We caught a few caddis flies in the trap, a weevil and a grass bug. We could hardly see the canal in the inky black outside and all was very still with no breath of wind. Peace perfect peace.

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Then in an explosion of white and red stars we were treated to a brilliant firework display, sizzling, banging and spiralling across the Sawley sky. We stood outside to enjoy the show. Later it started to rain and that signalled the premature end of the moth session so we packed up our gear.

This was a trial run, out of season, from now on the nights will be very long and very cold, not many moths fly in the winter months. We might pick up a November moth or a December moth but we have decided to wait until the warm days of spring herald the 2016 mothing season to find out more about the moths of the Trent Lock area. Watch this space!

Marion Bryce 7 November 2015

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