I found a few of these on the fritillary stems. Small and very brightly coloured, I didn’t know what they were, but with a bit of googling I think I now do. They are red lily leaf beetles. Not native to the UK they cause a lot of damage to lilies (obviously) and other plants.
I’ll have to have another look tomorrow. There is a significant risk, judging by the action going on here, that we could have a lot of beetle larvae soon. I would quite like the fritillaries to survive through to next year, so preemptive action may be necessary.
The garden - even its pests - has been such a joy these last six plus weeks. The lockdown/ shielding experience has just confirmed how important it is to our health and well-being. Not to have a patch of green-space outside for ourselves in these circumstances would make life so much more difficult.