Dock Bug

Dock Bug (Coreus marginatus)

I spotted a new insect for the garden this afternoon, while hanging out with my binoculars hoping for some passing migrant to drift by. This is a Dock Bug (Coreus marginatus), one of the UK's many shield bugs. Though similar in appearance to a handful of other species, it can be distinguished by its "large size" (just over half an inch, or 15 mm, which is big for a shield bug) and by the two tiny horns between its antennae. Those horns are tough to see in the picture above, but if you click to enlarge it and squint, you just might manage. The broad, curved abdomen, which is wider than the pronotum (the first thoracic segment, just behind the head), is also distinctive. As you might infer from their name, Dock Bugs feed primarily on the fruits and seeds of dock plants and their relatives — and there are plenty of those growing wild in the surrounding countryside. According to Collins Complete British Insects, this species also feeds on rosebuds and soft fruit, which is likely to make it unpopular with our neighbors. The book also says that Dock Bugs congregate in numbers in the spring and fall, just before and after hibernating. I found only a single insect, so I guess it's been out of its hibernaculum for a while.