Wednesday, 2 November 2016

Possible Stigmella hybnerella leaf mine - help needed

I collected this Hawthorn leaf from the coastal path a couple of days ago.  I think it looks like a vacated Stigmella hybnerella leaf mine, but I am wondering about the slender part of the gallery - it is meant to have "black linear frass with narrow clear margins" but this gallery doesn't look as clear as other examples I have seen online.  Using the key I haven't found an alternative that it could be.  The dark patch behind the gallery is present on other parts of the whole leaf so does not seem to be part of this leaf mine.  Any thoughts?
Possible Stigmella hybnerella mine
Early gallery in detail


6 comments:

  1. Sorry Sarah, this looks like an old mine and I can't say what it is to be honest. Maybe someone else will have a comment later.
    We have very few records for leaf mines and only one for this species. Just looking at this year's records we have not recorded anything without a larva to aid the identification.

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  2. I agree that this particular mine looks too old to be sure. But it may be hybnerella. I don't know about Ceredigion, but I don't think hybnerella is all that scarce. If it's possible it may be worth returning to the bushes and seeing if there are any more and judging the ID by what else you can find. You should find plenty on Hawthorn of other mines at this time of the year, anyway. I agree the black smudges are not part of the mine - they are probably fungal infections or similar, as the leaves lose their ability to resist infections. It makes the mines harder to see, unfortunately.
    If you don't know it already, try Bladmineerders Nederlandse (Spelling?) website - it is in English if you scroll down and is very comprehensive.
    Andy King.

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  3. Thank you both for taking a look at it for me - all your info. is really useful. I may have left it a bit late this year for finding leaf mines with larvae in, but I'll have another look at this particular Hawthorn soon.
    Ina, on the same day I found a leaf mine of Stigmella plagicolella on Blackthorn which didn't have a larva in it, but it was very distinct. Let me know if you would like to check it.

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  4. There are many leafminers which can be safely recorded even when vacated, including S. plagicolella on blackthorn which is distinctive and usually abundant. Unfortunately the hawthorn Stigmella mines are tricky, particularly when vacated (the yellow or green colour of the larva in occupied mines is a big help).

    There is still plenty of time for recording miners this year, especially in 'green islands' on fallen oak and beech leaves.

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    Replies
    1. Thanks George, that's really helpful. I'll keep trying....

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    2. Thanks to all. I have a habit of not making myself clear when typing...I was referring to Hawthorn mines in my previous comment.
      Sarah, as George has said your plagicolella is fine.
      We have the grandkids here at the moment and we found lots of green islands on our walks, but 'Poo-sticks' proved much more interesting after the first minute or so! ;-)

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