Coccidula rufa (Herbst, 1783)
This is a generally common and often abundant species occurring from lowlands to about 1000m throughout Europe from the Mediterranean to the UK and the far north of Scandinavia and extending east to Asia Minor, Siberia and Mongolia. It is generally common and usually abundant throughout England and Wales, including the islands, and widespread though more local and sporadic across Scotland and Ireland though absent from the islands. Habitats include a range of wetland environments; floodplains , wet meadows, river and pond margins, marshes, reed beds and bogs etc, but also drier areas among vegetation on dunes and river estuaries. Adults occur throughout the year, they overwinter in litter or plant stems in marginal areas and become active early in the spring among vegetation, typically on rushes, sedges and reeds but they will often be seen in flowers and we have beaten them from hawthorn blossom in marginal situations. During late spring and summer they disperse by flight and may be found far from wetland environments e.g. in parks and gardens or among crops. Mating occurs mostly in the spring, though pairs will often be seen later in the year, and eggs are laid in batches on leaves and stems of waterside plants, larvae develop through the spring and summer, they pass through 3 instars (although some sources quote 4) and pupate attached to stems. The life cycle is brief and new-generation adults appear from mid-summer. Both adults and larvae are aphid predators, they will generally consume any aphids they encounter but are widely quoted as predators of Hyalopterus pruni (Geoffroy), a species which attacks a wide range of Prunus species (mainly plum and apricot) but that breeds on its summer hosts which include a range of marginal plants but more especially Phragmites (reeds). Unlike the brightly-coloured adults the larvae are drab pale to dark grey, they are elongate and deeply depressed between the thoracic and abdominal segments, have 3 longitudinal rows of tubercles on the upper surface and a further row along the lateral margin, they lack urogomphi, have slender and relatively short legs and each body segment has long erect hairs. The pupae are also drab, dark grey becoming paler as they develop, shiny and finely pubescent throughout. Both larvae and pupae are easily spotted, larvae as they roam the foliage and stems, and pupae attached to stems etc.
2.5-3.0mm. Elongate and discontinuous in outline, entirely red or with the area around the scutellum or shoulders darker, underside red with an extensive black area covering much of the thorax and basal abdominal sternites. Dorsal surface finely pubescent throughout. Antennae much longer than the width of the head and typical of the family with a narrow 3-segmented and truncate club. Pronotum transverse, rounded laterally and broadest at or in front of the middle, evenly convex and lacking fovea or grooves and finely and quite densely punctured throughout. Elytra elongate and parallel-sided or only weakly broadened behind the middle, with distinct shoulders and continuously rounded apically, very finely punctured throughout and also with larger punctures that run, for the most part, in longitudinal lines. Legs long and slender with 4-segmented tarsi that appear 3-segmented as the tiny third segment is mostly hidden within the large and bilobed second segment, claws bifid. Among our UK fauna only Coccidula scutellata (Herbst, 1783) has a similar body shape and size but this has a series of discrete black markings across the centre of the elytra.