Anthocomus fasciatus (Linnaeus, 1758)
This widespread western Palaearctic species occurs in lowland situations across Europe from the Mediterranean north to southern Fennoscandia and the UK and east through the Caucasus, Syria and Palestine, it is generally very local and in many areas of central and northern Europe e.g. Poland it is sporadic and rare. In the UK it is a very local species of southern and central England and Wales north to the Humber; it is generally absent from western areas and seems to have decreased in abundance over recent decades. They occur in a range of mostly dry situations such as parkland, grassland, gardens and woodland and hedgerow margins, appearing from early May and persisting into July or August. Adults are polyphagous; they generally occur in small numbers, often only as individual specimens, and may be found on a range of flowers, especially umbels and, in the spring, Hawthorne blossom, where they feed on pollen and predate small insects and mites etc., they are active in warm weather but often prefer flowers in shaded situations. Adults may be found by sweeping suitable habitats or by searching flowers but may occur in any fairly dry situation with a supply of prey; e.g. we have swept them from nettle beds and they have been recorded from windowsills and walls of houses and sheds. Mating occurs early in the season and females oviposit on wood or in the soil where the larvae will develop through the summer feeding on subcortical beetle eggs and larvae within galleries or among compost etc., on the continent they have been found developing among compost in flower pots and in early spring are sometimes found at windows indoors after emerging from stored firewood etc.
Adults are distinctive due to their small size and colouration and should not be confused with any other UK species. 2.9-3.1mm. Forebody dark metallic green or greenish blue, elytra black; each with a red or orange transverse macula across the middle and pale apical area, the beetle must be seen in bright sunlight to appreciate the vivid nature of these colours. Dorsal surface finely and densely punctured and pubescent throughout. Head transverse with large convex eyes and long basally-converging temples, the vertex is weakly convex and the frons flat, with several long and outstanding setae behind each eye and across the clypeus. Antennae inserted laterally some distance in front of the eyes, 11-segmented and weakly serrate in both sexes. Pronotum quadrate or weakly transverse, with rounded anterior and posterior angles and lateral margins almost parallel in the male; converging towards the base in the female. Elytra elongate, more so in the female, and broadened from the basal third, with narrow sloping shoulders and separately-rounded apical margins. The pattern of red maculae is distinctive; the central maculae are broad, rounded at the apex and do not reach the elytral suture, those at the apex parallel-sided and joining at the suture. Ventral surface shiny black prosternum and apices of the abdominal ventrites variously pale, the red eversible vesicles on the lateral margins of the thorax and basal abdominal segments are usually visible even when contracted. Legs long, slender and entirely dark in colour although they may sometimes appear pale due to the fine and dense pubescence. Pro- and mesocoxae convex and projecting, metacoxae transverse and flat, trocanters long, narrow and connected obliquely to the posterior margin of the femora which are only weakly, if at all, broadened about the middle. Tibiae slender and parallel-sided; pro- and mesotibiae straight, metatibiae curved in both sexes but a little more strongly so in the male, without apical spurs. Tarsi 5-segmented, without dilated segments although the basal segments of the middle and hind tarsi have narrow ventral lobes.