Danny Arnold on Leaf-mining Micro moths

Inspired by Danny's talk last week, Mark headed out into the wilds of Gruinart Wood, peering at bramble leaves until he found evidence of the legendary leaf-mining micromoth 'Stigmella aurella' - specifically the tell-tale track made by the larvae in the leaf.

This is the adult moth - you can see the evidence for the larvae that Mark found at

Moth Hunting

Mark's record of this moth is a first for Islay.

This weekend, Pat Roy (who had also been at Danny's talk)  found evidence of a further leaf miner -  this time on Hazel at Dun Nosebridge.

We reported this to Danny who replied as follows:

"Hazel is one of those ubiquitous host plants that a great many moths feed on BUT Stigmella aurella is not on the list......(as far as I know)
However, it is likely to be one of two other possible Stigmella species.....

either 75 Stigmella floslactella
or 111 Stigmella microtheriella .

........ if you want to get ‘into it’ a bit more......the S. floslactella has a mine very similar to the S. aurella....the mine getting wider and wider as the larvae tracks through the leaf.

The microtheriella has the same sort of track mine too, but the mine, once widened out....tends to stay the same width for most of its length......very subtle differences.

Both mines are very similar and around at the same time of the year ie now...

.....so it isn’t conclusive really for either and shouldn’t be considered as a species ‘record’ just from the mine......

You could of course, check the mine against the light and see if the larvae is still in the mine. If it is, then you could put the twig with the leaf on in a glass jar and store in a cool place over winter and see what emerges next spring....that would be conclusive."

Also keep an eye out for the other Bramble miner......Emmetia marginea. This produces this funnel shaped mine on Bramble....

This is the adult moth 'Emmetia marginea' - could we produce another first for Islay?

Leaf miner is a term used to describe the larvae of many different species of insect which live in and eat the leaf tissue of plants. The vast majority of leaf-mining insects are moths (Lepidoptera), sawflies (Symphyta) and flies (Diptera), though some beetles and wasps also exhibit this behavior.

Like Woodboring beetles, leaf miners are protected from many predators and plant defenses by feeding within the tissues of the leaves themselves, selectively eating only the layers that have the least amount of cellulose. When attacking Quercus robur (English oak), they also selectively feed on tissues containing lower levels of tannin, a deterrent chemical produced in great abundance by the tree.

The precise pattern formed by the feeding tunnel is very often diagnostic for which kind of insect is responsible, sometimes even to genus level. The mine often contains frass, or droppings, and the pattern of frass deposition, mine shape and host plant identity are useful to determine the species of leaf miner. A few mining insects utilise other parts of a plant, such as the surface of a fruit.

Some patterns of leaf variegation are part of a defense strategy employed by plants to deceive adult leaf miners into thinking that the leaf has already been predated. (Wikipedia)