2016 November 24

 

   Jeremy Tatum writes:  The first European Winter Moth to appear on this site this year was on October 20, a rather early date, but they have since been abundant, as usual, in November.  Now Annie Pang sends us a puzzler from her back porch in the Gorge area yesterday, November 23.   Winter moths in Victoria are usually the European Winter Moth O. brumata, and we usually have to go out into the countryside (e.g. Goldstream Park) to see the native Bruce’s Winter Moth (“Bruce’s Spanworm”) O. bruceata.  Sometimes it is not difficult to tell the two species apart; at other times it is difficult.

 

   Given the locality where Annie photographed her moth, it is probable that it is brumata, and this opinion is shared by other “moth-ers” whom I have consulted.  Yet I believe (I’m a one-man minority so far!) that Annie’s moth shown below may be bruceata.

I base this on the conspicuous dark H or X in the middle of the forewing, which I believe to be diagnostic.  However, since we are not all in agreement on this, I shall label it bruceata/brumata.  Opinions (with reasons!) from viewers will be more than welcome, as will additional photographs of either species.

 

   One argument against my preference for bruceata is as follows.  In the undoubted examples of bruceata that I have seen, the cell between the two lower arms of the H is often darker than adjacent cells.  This is not so in Annie’s moth, which is therefore a point in favour of its being brumata.  Thus I may be said to be wavering.

 

Winter moth Operophtera bruceata/brumata (Lep.: Geometridae)  Annie Pang