Leaf-miners are a largely ignored group of insects from four groups: micromoths, flies, sawflies and beetles, and hopefully the scheme will raise awareness and produce many records for these groups and perhaps result in some new species for Ireland.
I also produced an introduction to leaf miners which will help people to identify their finds. The introduction and checklist can both be downloaded from here.
Leaf miners are the larvae of insects, and they can be detected by the track they make as they feed inside the leaf. Since they spend all of their larval life inside a leaf, they are very small: some of the adults are only 2-3 mm long.
Mines are identified primarily by knowing the host plant: many miners feed on a single plant or family of plants, so knowing the host plant immediately reduces the number of miners to be considered. Once we know the host plant, then further identification relies on shape of the mine, pattern of the frass (dung) in the mine and perhaps details of the larva or pupa.
Here's a shot I took of the fly miner Phytomyza ranunculi on Lesser Celandine:
|Phytomyza ranunculi on Lesser Celandine|
There are two main possibilities for this mine, the other being Phytomyza ranunculivora, which has the frass in more discrete lumps:
|Phytomyza ranunculivora on Creeping Buttercup|
Although Phytomyza ranunculivora hasn't been found in Celandine in UK or Ireland, it does use that plant in other parts of Europe, so it's always wise to check in case we can add a new foodplant for that species. The photograph above shows it on Creeping Buttercup, which is closely related to the Celandine, and was the first (and still only!) Irish record when I found it in 2010.