A tortoise beetle, Cassida vibex
We had a good day at the Radnor Fringe Festival in June, taking people to see the orchard site and discussing the management of it... and looking for critters, of course! We didn't spend a lot of time on that, but it was certainly worthwhile, as we've added another species to the county list! Tortoise beetles are really, really cute: essentially little green tanks with shields over their heads. They feed on a variety of different native plants, but are never so abundant that they have much impact on them.
There are a few species of Cassida, including the common green C. viridis, and some rarer ones that are restricted to the southern parts of the UK. One of those is the rather lovely Cassida vibex, which has some brown markings, and a bronzy iridescence. It is previously known from southern England, and a few patches further north (including Shropshire, and a few records in northeast Wales). Until now, there have been no records from Powys or other central parts of Wales, so this is another species that's inching its way into the colder and wetter climate zones like ours. They feed mainly on thistles, and some other plants, and you'll need to look closely to spot it... but it's worth the effort!