Reddish Vale Country Park
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The Green Dock Leaf Beetle, Gastrophysa viridula, is a green beetle which often has a strong golden or bluish sheen.
The male has a typical leaf beetle shape, but mated females become grossly distended, with their wing cases perched saddle like on top of the shiny black abdomen.
There are over 250 species of leaf beetles in Britain. Adults and larvae nearly all eat leaves, many species are a serious agricultural pest.
The green dock beetle's breeding season is from March to October. There are 2 to 4 broods per year, with the last brood hibernating as an adult. The female lays over 1,000 eggs, laying them in clusters of 20 to 45 on the underside of the food plant's leaves. The eggs are oval in shape, and are cream to yellow, turning orange prior to hatching. After about 3 to 6 days, the larva hatches from the egg. It varies in color from greenish gray to dark brown. Its body is segmented, and will reach a length of 8 mm. Young larvae will drop to the ground if disturbed while feeding, while older larvae secrete a substance which repels competitors from eating the food plant leaves. After three instars, the larva pupates in a burrow about 2 cm underground. The adult emerges 6 to 9 days later.
Green Dock Leaf Beetles can be found May to August on docks and related plants, usually in a waterside habitat.
Green Dock Leaf