Firstly is it safe to ID this as Coleophora albitarsella from this image, or does it need dissection? It would seem that the white tarsi are distinctive of this species, but I'm not sure whether there may not be others which look similar.
Finally, does this look a good candidate for Hoary Footman? I don't think it's possible to check the hind wing without euthanasia, which I'd prefer to avoid if unneccessary! I'm not sure Hoary Footman has made it this far north yet.
I did have a similar one recently, and on that individual whilst the hindwing certainly looked pale, there appeared to be a hint of pale straw in it, so I decided against.
Maybe dissection is the only way to be sure?
Maybe dissection is the only way to be sure?
Thanks
Phil
Hi Phil, a good clear image of Coleophora albitarsella, preferably from the side, seems to be acceptable on iRecord at least at the level of 'considered correct', although that judgement will remain with your CMR. The second image looks more like Blastobasis adustella to me, where there appears to be a pale 'chevron ' at about one-third, although it's not very clear. On the problem of checking wings, there is a way of anaesthetizing moths that allows recovery as noted in the WTL Guide (under the November moth agg. entry): exposing the moth to ethyl acetate vapour in a sealed jar for sufficient time to stop it moving. I have found that moths always recover from this after some minutes, giving enough time to check the wings. WARNING: ethyl acetate is available in some types of nail varnish remover, but it is both flammable and toxic to us so do not breathe it in!
ReplyDeleteHello Phil,
ReplyDeleteIf the white tarsus (final section of each leg before the claws) is clear in an image and the rest fits, as it does in this case, then albitarsella is one of the few Coleophorids which can be done safely from a photo, so I'd accept this one without the need to keep it. The next looks to me like a darkish Blastobasis adustella. Hoary Footman could turn up anywhere in our three counties nowadays so that would be a good specimen to keep for dissection if it is potentially new for your site. Hoary and Scarce can't be separated safely without reference either to the hind-wings (reasonably easy to check although may take some practice if the moth is to survive the experience!) or else to their genitalia.
Thanks John and Dave,
ReplyDeleteI will release the albitarsella.
Not sure how/why I missed Blastobasis adustella...I should have been able to do that.
Re anaesthetising, I do use ethyl acetate, and as you say John, the moths always seem to recover; but I have found it rather tricky with Scarce Footman types to open the tightly rolled wings to expose the hindwing without causing some damage. I will see what I can do, but as it will be new for the site I suspect dissection will be the final arbiter.
Re Hoary Footman: I have successfully used the following technique to determine the colour of the hindwings. It requires 2 people and a french window. Person 1 is equipped with a pencil (or similar). Place the moth c1m from the window. Person 2 has a camera set to continuous shooting and points it to a point midway between the moth and the window. Person 2 calls '3, 2, 1, go'. On go person 1 prods the moth with the pencil until it flies and then calls out 'now'. The moth invariably flies towards the window. Person 2 presses the shutter and keeps it there. With luck the flying moth with the hindwings visible will be in at least one frame. However, I have found that HFs have pale grey legs while SF has yellow legs. I will post a couple of photos on the website.
ReplyDeleteThanks Dave, an interesting solution, and very similar to a technique I use to identify 'white' butterflies in flight...i.e.shoot at high speed in burst mode and look for a frame that has the wings clear enough to enable identification.
ReplyDeleteBut before I had read your post, I had in fact decided that the moth would have to go for dissection, so I popped it in the freezer and now have seen the hindwings. In the photo you have posted, the hindwing does look very white, whereas mine is certainly pale, but not actually white, with just a hint of very pale straw. As to the legs, they appear to be grey on the upper surface and yellow below, but certainly not all yellow. It will be interesting to see what dissection reveals!