Gastrophysa viridula (De Geer, 1775)

Taxonomy: Polyphaga > Chrysomeloidea > Chrysomelidae > Gastrophysa > Gastrophysa viridula

Common name: 

Green Dock Beetle

Images

Gastrophysa viridula
Gastrophysa viridula
Gastrophysa viridula
Gastrophysa viridula
Gastrophysa viridula

Description

Size: 4-6mm
Basic colour: Metallic green
Pattern colour: None
Number of spots: None
Spot fusions: None
Other colour forms: Sometimes
Pronotoum: Metallic green
Leg colour: Metallic green

The breeding season is from March to October. There are at least 2 generations per year, possibly up to 6, 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's leaves. After three instars, the larva pupates in a burrow about 2cm underground. The adult emerges 6 to 9 days later. Adults create holes around 1cm in diameter in leaves. Flies strongly.

Biology

Status: Common and widespread in Britain; more western distribution than G. polygoni.
Habitat: Variable including wet areas, heathlands, woodland edge, grasslands, dune slacks, fields, gardens.
Host plant: Docks and other Rumex, especially Broad-leaved Dock, R. obtusifolius.
Overwintering: Unknown
Food: Rumex (docks, sorrels), sometimes other Polygonaceae and buttercups.
Other notes: During the mating season, females have enlarged abdomens. The antennae are serrated and are medium in length. Usually metallic golden-green or green, sometimes brassy/bronze, rarely blue. Last six antennal segments black.

Articles

Salisbury, A. & Platoni, A. (2013). The green dock beetle, Gastrophysa viridula (De Geer) (Chrysomelidae) - a pest on Begonia (Begoniaceae), a new host record. The Coleopterist 22(3): 124.

Distribution (may take a minute to appear)