Two very common micros on Nettle as larvae now are; 385 Anthophila fabriciana and 1405 Mother of Pearl Pleuroptya ruralis. Which just goes to show how silly the so called division between "macros" and "micros" is , A.fabriciana is very small and P. pleuroptya is as big or bigger than many macro moths, yet both are classed as micros !
I found plenty of spun together nettle tops this morning with both larvae in residence. It can be quite hard to separate the two as fabriciana (bottom photo) do not look as clearly marked as the ones shown from Ian Kimbers website. Both larvae are small and light green in colour in the early instars and only separate out to distinctive larvae as they get to the last instars. The easiest way to separate them by eye alone is that Mother of Pearl (shown in the top photo) are larger and a more translucent green, hard to describe but easy once you have seen both. At the moment the larvae are usually in the growing tips of very small nettles but as the plants grow the larvae tend to be found anywhere on the plant in a leaf spun closed. Lots of other species use nettle in this way later in the year but now I think you will only find the to species mentioned. Should you wish to rear both species they are dead easy, simply add fresh nettles leaves to the container as the old leaves shrivel and the larvae will move to the new leaves to spin up and feed. As a general rule for all larvea at this time of year look for trees or plants that get plenty of sunshine as these tend to be the first ones with larvae whilst its still cold.