Malachius bipustulatus (Linnaeus, 1758)
Green Malachite Beetle
A generally common and often abundant species throughout Europe to the north of Scandinavia and the U.K., extending east to Asia Minor and Siberia and in many countries the most common member of the family. Here it is common across England and Wales, becoming less so in the north and rare in Scotland. Through most of the range they are insects of lowland meadows and agricultural borders etc., adults appear from late April or May and are soon abundant on flowers in a wide range of situations, usually where there are hedgerows or trees and shrubs, and they generally persist into July or August. Adults feed on small insects as well as nectar and pollen and spend much of their time on flowers, mostly those of grasses or members of the Asteraceae, Apiaceae and Rosaceae, they are generally active and take flight readily when disturbed. Both sexes posses large brilliant-red eversible sacs along the ventral surface of the thorax and abdomen, so called cocardes, that emit defence odours when they are alarmed and which are readily seen when the beetles are netted or handled. Males posses brightly coloured lobes on the inner margin of antennomeres 2-4 which are used to transfer sex pheromones from a glandular area on the head between the antennal insertions and which females find powerfully attractive. During courtship the male antennae are held forward to attract a female which will approach and consume the pheromone secretions prior to mating, this behaviour is usually protracted and may continue for up to an hour but will not always lead to mating and it is thought that pre-mated females continue to visit males and consume the secretions but do not mate. This behaviour is easily observed in males high up on grass stems and seed-heads signalling for females with the antennae held out straight. The cocardes are often inflated during courtship and mating. Later in the season females lay eggs in bark crevices or among tussocks where the larvae will develop through the summer. Larvae are predatory, consuming other insects and their eggs and larvae and also slugs etc., and very distinctive; elongate and cylindrical with the thorax flattened, creamy to orange or bright red in colour with the head and the terminal abdominal segment dark, there are two parallel dark lines on the prothorax and a pair of more laterally placed dark marks on each thoracic segment, the head is quadrate and parallel-sided and the terminal abdominal segment has a pair of curved urogomphi. The legs are relatively long and the larvae can be very agile as they hunt under bark or among tussocks. The life-cycle is univoltine.
5.5-6.0mm Distinctive among the U.K. fauna and only likely to be confused with Cordylepherus viridis (Fabricius, 1787). Brilliant metallic green, often with bronze overtones, with the anterior pronotal angles and elytral apices red. Entire dorsal surface with moderately long erect dark setae. Head quadrate though usually inserted into the prothorax and so appearing transverse, widest across the convex and prominent eyes and with long curved temples that narrow to the base. Vertex weakly convex or flat, anteriorly with a deep transverse impression between the eyes, male extensively yellow anterior to the eyes, female with the labrum yellow, anterior margin of the clypeus curved backwards in both sexes. Antennae filiform; female with segments 2-4 weakly serrate, male with segments 2-4 modified internally. Pronotum transverse and flattened, depressed medially and towards the hind angles, rounded laterally and internally, basal margin straight and strongly bordered. Elytra elongate and broad; dilated behind the middle to continuously rounded apical margins, finely punctured and densely microsculptured and without striae. Legs dark metallic. Tarsi 5-segmented, segments without lobes. All claws with a distinct lobe at the base.
Less bright green, often to some extent blue, elytral apex less distinctly red, anterior pronotal angles not red.
Pronotum less transverse, almost quadrate.
Male antennae unmodified, female antennomere 2 less strongly serrate.