Friday, 8 June 2012

Rain, Rain, Rain

The title says it all.  It's still raining!  Cool, wet and windy today but we braved the foul weather to do a little shopping in town.  This gives me the opportunity to post a picture of a moth which was found in our garden and which has been providing me with a good deal of trouble as I've tried to identify it.
I eventually managed to put a name to it as a Melanic form of a Scalloped Hazel Moth (Odontopera bidentata f. nigra).  Usually, Scalloped Hazel moths are a rather pale, greyish-brown with a dark spot on each wing and a whitish line across them.  The melanic form however, being so much darker over-all, makes life a bit more tricky.
There is a theory that these darker forms of various moths have declined in recent years following the clean-up of our atmosphere.  When chimneys all belched soot and factories filled the air with dirt, almost everything was covered in black filth.  Buildings were blackened, tree trunks were blackened and as a result, the melanic forms of these insects, were beautifully camouflaged against them. Having cleaned up our act, buildings have been cleaned and tree trunks have lost that sooty black coating, making the darker moths stick out like a sore thumb.  This of course has made them more vulnerable to predation.
Result.....fewer melanic - or dark form - moths.  To add further weight to the argument, melanic form moth numbers have decreased more dramatically in the industrial north than in the south of the UK.  Makes sense!
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