Green Dock Beetle
They’re a metallic green in colour, about 4mm long with the females slightly longer at about 7mm. The female also has a swollen black abdomen prior to egg laying during the mating season which lasts from March to October.
She lays clusters of tiny yellow eggs on the underside of dock leaves, laying up to 1,200 eggs in two to four broods a year
The adult’s life span is only a couple of months but they can hibernate over winter.
As their name suggests Green Dock Beetles feed almost exclusively on dock and sorrel but if these are not available to them or are in short supply (neither being the case at the Marina!) they will eat from the cabbage family as well as the borage, violet and buckwheat families. These choices are not high on their menu though as their larvae will not develop fully if they feed on these plants.
The green dock beetle’s natural predators are insectivores (such as birds and frogs) and parasites.