Coreus marginatus (Linnaeus, 1758)
Commonly known as “Dock Bug”
Family: Coreidae (Leather-bugs)
Length: 13 to 15mm
Coreus marginatus is widespread and common herbivorous species, found in Southern Ireland and England, as far north as the midlands. Across central Europe and Asia, down as far south as North Africa. Colours vary from a light brown to a reddish-brown body, which is found mainly on the younger Coreidae marginatus. In appearance, the nymphs differ from adults, they are heavily spined and also differ in colouration. Also, their antennae looks out of proportion compared to their body size.
Habitat: prefers lush vegetated covered sites, open dry and damp areas in gardens, parks, woodland edges and hedgerows. All “Dock” leaved related plants, are a favourite vegetation. Adults will be seen in September feeding on blackberries.
One generation a year, will often be seen in “family groups” amongst lush vegetation associated with Dock leaves.
As a defensive mechanism against predators, male and females can give off a very strong pungent odour, produced by the scent glands, located in the middle of the thorax (chest).
The Dock Bug like other Coreidae, live for about a year. The brown eggs are laid between late May through to middle of July. About three to four weeks after hatching, the nymphs go through five consecutive nymphal instars. The young nymphs will feed on leaves and stems, the more mature nymphs as like the adults, will also feed on seeds. Most of the nymphs will be adults from August onwards.