Omaloplia ruricola (Fabricius, 1775)
Although very widespread and often common this species is rather patchily distributed through Europe from Spain to Central Italy and the Balkan peninsula and north to southern Scandinavia, further east it extends through Russia, except in the far north, Kazakhstan and Mongolia to China. In the UK it is a very local and generally rare insect of southern England and South Wales extending west to Dorset and north to South Yorkshire. The typical habitat is dry calcareous grassland and woodland margins, often on south-facing slopes exposed to the sun, where adults occur from late May until July or August. Adults generally become active during late morning when they may be observed in flight or crawling or mating on pathways and areas of exposed chalk or soil, they remain active until early afternoon and there may be another period of activity in the evening or at night. Mating occurs after a period of feeding during June and is soon followed by oviposition; eggs are laid among vegetation in the soil and larvae develop during the summer, feeding on roots of herbaceous plants, shrubs and grasses. Fully-grown larvae burrow deeper into the soil during late summer and here they will overwinter, moving up in the spring to pupate among grass roots etc. Adults feed on foliage and developing leaf and flower buds of all kinds, here they are never a pest but on the continent, and especially further east, large populations may develop and cause serious problems to crops as they damage flowers and developing buds of a wide range of soft fruits, grapevines, ornamentals such as roses, herbaceous plants, grains and various tree-fruits. Commercially grown ornamental shrubs such as various Viburnums may also be attacked; both by adults directly and by larvae feeding upon the roots, more generally the larvae may become pests among cereals, beets and clover crops. The species is sometimes quoted as having an association with ants but this seems not to have been investigated.
Omaloplia ruricola 1
Omaloplia ruricola 2
A small, 5-7 mm and distinctively coloured chafer; entirely dull black with the elytra extensively brown but entirely black specimens are not infrequent in the UK. The superficially similar Phyllopertha horticola (Linnaeus, 1758) may be distinguished by the generally larger size, 7-12mm, and the metallic green pronotum. Dorsal surface of head and pronotum and lateral margins of elytra with long outstanding dark pubescence, antennae pale with a small club in both sexes. Pronotum broadest across the base and evenly curved to a round anterior margin, basal margin finely bordered and quite strongly sinuate towards the rounded posterior angles, surface evenly convex, moderately strongly and densely punctured and with scattered pale setae. Scutellum large with curved lateral margins and rounded apex, the surface finely and sparsely punctured. Elytra typically extensively pale brown with darker margins and weakly impressed and finely punctured striae, interstices much wider than the striae, finely punctured and sparsely pubescent. Legs long and robust; middle and hind tibiae with two groups of short and stout spines externally, hind tibial spurs widely separated. Front tibiae fossorial externally, with long and curved apical teeth. All claws with a large internal lobe.