Dock Bug Coreus marginatus

Dock Bug Coreus marginatus

I have featured this extraordinary ‘bug’ before in a previous post, and you can learn more about it there if you wish to: Dock Leaf Bug. However, please note the two converging lobes on the nose in the second image down. This is diagnostic of this species.

Dock Bug Coreus marginatus

Dock Bug Coreus marginatus

When I came across several of them this morning on a local woodland margin, I also saw two instars which can be seen below. Note the differences between the adult on the left and the final instar on the right in the image directly underneath.

Dock Bug Coreus marginatus adult and final instar

Dock Bug Coreus marginatus final instar

Below is a mid instar, and comparisons can be made between the two stages with the final instar above.

Dock Bug Coreus marginatus mid instar

August 2017, Staffordshire, England.

Dock Leaf Bug

Coreus marginatus

Dock Bug (Coreus marginatus)

Sometimes called the ‘Brown Squash Bug’, ‘Squash Bug’ or Dock Bug’, this is a large brownish shield bug with rounded shoulders and orange to peach coloured striped hard wing base. It also has two tiny horns between its dark-tipped antennae. Length 12 to 15mm.

Dock Bug (Coreus marginatus)

When threatened this bug releases an obnoxious chemical in defence which can turn the skin brown if contact is made. It can be very hard to wash off and remain this way for many days. With this reference in mind, it is sometimes known as a ‘Stink Bug’. It hibernates in all life stages. It feeds mainly on the fruits and seeds of dock (rumex), and their relatives (Polygonaceae). It can also be a pest to rose buds and soft fruits, especially squash (Cucurbita).

Dock Bug (Coreus marginatus)

Mostly observed in spring and autumn where they congregate before they hibernate. It is found in many habitats, including woodland verges, hedgerows, the edge of cultivated fields, meadows, wasteland and gardens. A widespread and common species found all over Europe and parts of North America. Common and widespread in southern Britain.

Photographs of Dock Bug (Coreus marginatus) taken May 2014, local field margin, Staffordshire. © Pete Hillman 2014. Camera used Nikon D3200, with Sigma 105mm macro lens.