Did you know that the sawfly gets its name from the way it lays its eggs? Innocuous little flies, like the beauty shown below (Arge pagana, one of the UK species that uses the rose as its larval plant), have an in-built saw-like body part that they use to cut a slot in their larval plant material and in that slot they lay their eggs.

On some plants, like the stems of the various Rosa species used by Arge pagana, the slot leaves quite a substantial scar and, this week, for the first time, I noticed one of these when checking Dog roses for leafmines. As you can see, there’s a healthy leaf bud right next to the scar so the plant doesn’t seem to have been damaged by the slot-making process, though the voracious larvae that hatched from the eggs earlier in the year may well have stripped the rose of many of its leaves.