Tuesday, 16 August 2016

Common but Confusing

                            1                                                        2

                             3                                                 4

No.1, a colourful version of Acleris laterana.  Or is it the Strawberry Tortrix  A. comariana?  The red markings would seem to be consistent with the latter name.  Fortunately the recording sheet I use permits the grouping of the two species together, thus avoiding the need for a decision!

Few groups of moths causes me more consternation than the Crambids, and there's no avoiding the decision with them.  Sure, there are one or two species such as Eudonia pallida and E. delunella which are easy to name, but for the most part it's the three common ones I encounter here: Scoparia ambigualis, Dipleurina lacustrata, and Eudonia mercurella.  I think.  Take the three examples above, all caught last week.  2, I would name S. ambigualis, but isn't it a bit late for that species?  Could it be E. truncicolella?  3 and 4 are much darker, it's late summer, surely must be E. mercurella?  But the book (S&P) says 'E.mercurella never has any yellowish brown on the forewing'.

Confusion reigns!  I need to go on a Crambid course.  Any volunteers to hold one?

4 comments:

  1. Chris - Have a look too at Jon Baker`s excellent article on these `grey crambids` in Carms in the Newsletter No 9 (Aug 2007) in case it helps. I`ve found it useful in the past, but it`s easy to get confused with this group. I`ll have a look at your photos in due course (might be a while yet, as I`ve got a lot of `catching up` to do) but not today, as I`m still bone-tired after last night`s moth expedition!

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  2. The Acleris looks like one of the two regular forms of Acleris laterana, the other regular form being black & brown. Acleris comariana is much less regular than A laterana in the bits of S Wales that I have recorded in, although I have encountered it in some marshy areas.

    The Scopariines are very tricky. I agree with your thoughts on 2, 3 and 4, although the brownish scales on 3 are very odd (the curved subterminal white band surely rules out other species with toothed subterminal bands). No 2 is either ambigualis or truncicolella. Tricky...

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  3. No2 looks pretty grainy, I think safe to call that truncicolella.

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  4. Thank you one and all, at least I can safely be specific about these 4 moths! Ian, I wrote this piece straight after reading Jon's article for the umpteenth time, along with S&P, the Berkshire guide, UKMoths, and other sources I've picked up along the way, but none of them clears the confusion altogether. Perhaps it's an impossible task, with the common species being so variable and sharing some key features. Jon's article is helpful in providing a concise guide regarding what species to expect in Carms. at different times of the year.

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