Thistle weevil

Thistle-head Weevil (Rhinocyllus conicus)

While poking around in the garden recently, I came across a speckled beetle I didn't recognise – actually two beetles, busily making little beetles. I took pictures from every possible angle and retired to our in-home library to try to figure out what they were. A bit of research showed them to be Thistle-head Weevils (Rhinocyllus conicus), a distinctive short "nosed" species that specialises on various species of thistle. Their overall colour is brownish-black, with a regular pattern of pale speckles across their elytra (the hard cases that cover their wings). As you can tell from the ant in the background, they're pretty small, measuring at most 7mm (about 1/4 of an inch). Native to southern and central Europe, northern Africa and western Asia, they've spread significantly northwards in recent decades, including into the UK. Initially found only in southern coastal areas, they've further expanded their range, and are now locally common throughout much of England and Wales. They were introduced into North America, in a misguided attempt to control introduced thistles; while they did indeed feed on those introductions, they also attacked native thistle species and have become a serious invasive pest. They feed on leaves, primarily those near the flower heads, chewing a series of round holes. After mating, the female lays up to 200 eggs onto the bracts of flower buds. These hatch about 10 days later, with the emerging larvae developing for some six weeks before pupating. After a further week, the new adults emerge; most of these will overwinter. Given the number of thistles we have in the garden, I expect we'll be seeing a fair few of these weevils in the coming years.