The Dock Leaf Bug, shortened to Dock Bug, is called a Shieldbug in the UK (although experts separate its order,
Coreidae, from true Shieldbugs Pentatomoidea) and a Squashbug in North America (a term which has travelled to the UK). Like most Shieldbugs, it lives on plant sap, in this case the alkaline sap of the Dock Leaf that we use to neutralise the acid of stinging nettles.
Male and female are of similar appearance, mottled brown with brown membranous wings under shortened wing cases, brown legs and orange-brown antennae with black tips.
The underside. Shieldbugs and Squashbugs are also called Stink Bugs in North America, as they can excrete a stinky, noxious liquid if threatened.
The black upper abdomen and yellow lower abdomen seen when the wings are raised.
The Dock Leaf Bug can be confused with the less common Box Bug but the latter is longer and more slender with a narrower, more patterned "skirt" and different antennae.
Dock Leaf Bug nymphs (young) are shown on a separate page -- see link below.