This Plume moth, which came to my MV light last night is causing me some difficulty. I
would probably have passed it off as Brown Plume, but for the fact that, by
chance, I had just read about Stenoptilia zophodactylus in the Micro-moth Field Tips book, which
mentioned a white saddle, and to the naked eye, this moth certainly appeared to
have a contrastingly pale saddle.
Having now
examined my photos in detail, I still think it is S. zophodactylus,
rather than S. bipunctidactyla, which appears to be the likely
confusion species. I base this mainly on the disposition of the dark spots at
the base of the cleft, which matches the description in Sterling & Parsons of "two spots, the second of these fainter and obliquely displaced towards the
costa". Such a feature is not mentioned for bipunctidactyla, rather that
the spots at the base of the cleft in that species are fused. However there is
no spot at one third, nor are there any significant black spots in the terminal
cilia, though this doesn’t rule either species in or out since both should have
some spots.
The saddle in fact looks pale buff with white edges, rather than plain white, but
images of bipunctidactyla show the saddle as being roughly concolourous
with the other segments, with contrasting white edges, whereas
here the whole saddle appears contrastingly paler.
UK Moths says white legs are a defining feature and
also notes that its legs are thinner than its congeners—hard to say, but they
do look fairly thin—but only the middle pair of legs appear to be all white.
As far as I am aware, there are none of the food plants of either species in the vicinity!
Hello Phil,
ReplyDeleteThis little group are not easy to identify on sight. In Colin Hart's book "British Plume Moths", under zophodactyla he says of the saddle: "The colour of this saddle helps to distinguish this species from the closely related S. pterodactyla and the bipunctidactyla group. In S. pterodactyla the saddle is creamy-yellow, in the bipunctidactyla group it is white at the edges and light brown in the centre, but in S. zophodactyla the whole saddle is white." For me, your images rule out zophodactyla because the saddle seems to fit his description of the bipunctidactyla group. Another one for dissection, I feel!
Thanks Dave, I feared that dissection might be the answer, but sadly I didn't retain it. I could easily have done so too as it was very well behaved!
ReplyDeleteI must get that book for future reference.