The Holly leaf-miner

The leaf blotch made by the Holly leaf-miner

If you check out our one native species of Holly in Britain – Ilex aquifolium - then you are very likely to find our only native leaf-miner that lives on Holly. Not all things in natural history are that uncomplicated!!

The Holly leaf-miner - Phytomyza ilicis – is a tiny fly that spends most of the year living as a larvae or pupae “inside” the holly leaf, rather like a letter inside an envelope. There are many hundreds of species of leaf miner; not just flies however, as many are made by tiny moth species too.

The Holly leaf-miner lays its eggs in May and June, in the underside of a young Holly leaf. The eventual blotch on the leaf that the larvae make is green to start with, but over time it can often turn wine red. Also, usually there will be a dark spot in the middle of the leaf blotch, which is made up of frass (or poo) excreted by the larvae.

Some can turn a colourful red! 

Once you start to check out Holly to see if it has this little fly species, you will quickly realise just how common and widespread this species is – it seems to be on most Holly bushes and trees. You may never have noticed it before – but you will from now on!