Beer and treacle attracts moths!

10/02   Blackneck, Catcairn  Bushes.  NT96 59  13/6/2010
10/02 Blackneck, Catcairn Bushes. NT96 59 13/6/2010

Continuing last week’s article on ‘Moths and Mothers’ based on the talk to the SWT in Duns by Malcolm Lindsay.

Another method of attracting night flying moths is to paint fence posts with a mixture of old beer and treacle, moths are attracted to the rich smell and sit there supping up this sweet concoction, it is then easy to go round with a flash-light and see what has been attracted. By whom or when this method was dreampt up I do not know. Moths can also be identified at the caterpillar stage as most species are distinctive, some species which look alike at the adult stage are easy to tell apart as caterpillars.

Malcom then went on to describe some of the rare and special moths found at different locations across the Borders. One interesting new find is the Northern Dart, a species with an arctic/alpine distribution. It has been known in the Highlands for a long time and its discovery in the Tweedsmuir Hills was the result of a lot of research and hard work.

This species has a two year cycle - there are only adults every second year. You must search for it in the correct year, in the Tweedsmuir Hills it’s an “even year” as it was found in 2014. Where it is found in the Central Highlands it is on a different year cycle from the mountains north of The Great Glen.

To trap specimens, moth traps had to be carried up to near the top of the hills and run overnight on a mild calm evening, the trappers taking sleeping bags and a bottle of old malt whisky to make the night more bearable and they were rewarded with 65 specimens which proved that a good, large colony of this special moth lives in the Borders.

The reason this moth is on a two year breeding cycle may be to outwit a tiny predatory wasp which feeds on the caterpillars. The wasp is on a one year cycle so its numbers crash every second year when there are none or only a tiny number of caterpillars to predate, the following year when there are lots of Northern Dart caterpillars there are few predatory wasps.

On the coast another special moth is the Blackneck, whose caterpillars feed on Wood Vetch. There this isolated colony is at the northern edge of its distribution as there are very few records north of the Humber and it is not found anywhere else in Scotland. Our colony has existed since 1956 when it was found by Albert Long. Will it be one of the species to spread with global warming?

Our next SWT meeting in Duns Parish Church Hall is tonight, April 9, at 7.30pm. There will be a short AGM followed by talks by Myra Watson on South Uist, David Long on Albania and Roger Manning on ‘The Magic of Moorlands’. Everyone is welcome.