1. Elachista utonella?
2. Yponomeuta rorella
Is this species identifiable from an image, or is it impossible to ID unless bred from its food plant like the other three Yponomeutas? It is a species I have not come across before, but in recent days I have had two that visually seem good for the species, with a grey panel in the centre of the wing, and white on the dorsum and along the costa.
3. I have now had a third probable Caryocolum fraternella. One I have retained for dissection, and the second I released, but a detailed comparison of the images of the latest and the released specimen, show that they are different individuals.
Hello Phil,
ReplyDeleteI've had difficulty with separating those two Elachista species in the past so dissection is probably the way forward, although your example does look to be a very good match for utonella. I've seen both species in your general area of the county (utonella in Whitfield Wood and albidella near Tingewick) so either one could theoretically turn up in your garden.
I'd be happy to accept Yponomeuta rorrella from a decent photo. Your first image shows most of the important bits perfectly well, with the obviously greyish leading half of the forewing, smallish spots, that white smudge on the costa just before the apex and the darker grey fringe. The clincher, if it were necessary, would be to check the underside of the forewing where there should be a thin white strip along the costa. I reared some padella from larvae this year and some of the grey ones which emerged did have something resembling that white smudge, so care is needed when determining rorrella but most should be do-able. There have been huge numbers of them seen this year in eastern counties so most are probably migrants
Thanks for that very detailed response (as always!). I have the Elachista, so will get it dissected. And I'll "tick" the rorella!
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