Recently I have caught some moths which may be Eucosma cana - which would be a new species for the garden list if confirmed. I know that this species is similar to E. hohenwartiana (which in turn is similar to some other species). Several aspects led to my tentative identification of them as E. cana albeit that individual moths show some attributes better than others: the somewhat paler colour, the silvery edge to the ocellus, and what the Norfolk Moths site shows as a dark discal streak. I show three different individuals below: is my identification "safe", or should one or two go for dissection? I should say that all three have a forewing length of just about 8½ - 9mm, which is well within the size overlap range.
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| Moth 1. Newton Longville, 30th June 2021 |
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| Moth 2. Newton Longville, 30th June 2021 |
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| Moth 3. Newton Longville, 4th July2021 |
I normally just record any grey moths that appear to be in the Cnephasia genus as "Cnephasia sp." However, is this one significantly distinctive as to be safely identified as a dark example of Cnephasia stephensiana? As you can see from the bright background, it's not an underexposure! FWL 9½mm.
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| Cnephasia sp. Newton Longville, 4th July 2021 |
Tim Arnold
Newton Longville, Bucks
Hi Tim,
ReplyDeleteI suspect your three moths are all Eucosma cana but it would be worth getting them chacked if you still have them. In the field guide illustrations it looks as though it is going to be easy to separate cana from the hohenwartiana group and that is the case with the "typical" form of cana which is illustrated, but they're actually a lot more variable than you might think!
The other one is, as you say, a Cnephasia and quite probably stephensiana but that wouldn't be a safe ID without dissection. It is worth getting a few of different sizes and markings properly checked so that you can know what your site might produce. I get incertana, stephensiana, asseclana & communana annually, of which communana is always the first at the end of April/beginning of May, while I've had genitalana occasionally too. I suspect it'll be very much the same in your garden.
Thank you, Dave, for some good advice. I'll get a range of examples checked. I think I have two of the potential E. cana examples from 4th July and several from last night (Friday - I'm still working through photos - 83 species and counting).
ReplyDeleteGoing forward, I'll do the same for Cnephasia.