Both species begin by creating a small, triangular mine in Acer leaves, often in the middle of the leaf, before later rolling the leaf tips. Caloptilia semifascia does so on field maple, while C. rufipennella is found on sycamore. The leaf-cones on field maple are typically highly conspicuous, as the fold often deforms the shape of the leaf.
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| Leaf cone made by Caloptilia semifascia on field maple. Image: North Wales Lepidoptera |
The folds made by C. rufipennella are somewhat more subtle, with it making three progressively larger folds at different points along the leaf edge.
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| A leaf-fold made by C. rufipennella on sycamore. |
Neither species have all that many records from VC47, and are probably rather over-looked. Most records to date are from the eastern half of the county, which is typically where more recording is done. Caloptilia semifascia may be limited by the amount of field maple available in some parts of the county, however.
Here's the leafmines.co.uk key for moths mining maples (the leaf rollers are at the bottom). Also, do keep an eye out for other types of mine on these two trees as they are easy to identify. For both field maple and sycamore, there is a different species of Stigmella (making gallery mines) and a different species of Phyllonorycter (creating small blotch mines).
Last month's results and points tally
The June challenge was to find Lyonetia clerkella. I'd picked this species as I expected it to be very easy to find; however, it turned out not to be so easy with only two recorders being successful: JP (Aberbechan) & DHB (Henley). Perhaps it's having a poor year, but that's just the way it goes. If you did find it but have yet to tell me, let me know and I can amend the tally.
Points to date:
G Chambers - 1
C Boyes - 1
D Boyes - 2
T Ward - 1
J Pearce - 2
