Athous haemorrhoidalis (Fabricius, 1801)
POLYPHAGA Emery, 1886
ELATEROIDEA Leach, 1815
DENTICOLLINAE Stein & Weise, 1877
DENTICOLLINI Stein & Weise, 1877
Athous Eschscholtz, 1829
Athous Eschscholtz, 1829
This widespread and generally common elaterid occurs throughout the Palaearctic and Asian regions from lowland to mountain zones, it is widespread throughout the U.K. north to the Scottish Highlands and is one of our commonest species; here it is a predominantly lowland beetle becoming rarer up to 500m and absent above 600m. Adults may be seen in just about any situation including all types of woodland, moorland, grassland, dunes, parks and gardens etc. They are active early in the year, from March or April, when they can be seen basking on low foliage, especially nettles etc. in hedgerows, or beaten from Crataegus etc. as they come into leaf. They soon become abundant and may be swept from vegetation generally or observed on flowers of all kinds, especially Umbels and wild roses, the adults feed on pollen, nectar and emerging foliage. Eggs are laid in late spring in open, well-vegetated soils where the larvae will develop, feeding on plant roots and also other insects; they are known to predate larvae of the Winter moth, Operophtera brumata (Linnaeus, 1758), and consume dead insects and their larvae. Occasionally they occur in large numbers and may damage turf and shrubs etc. and on agricultural land can be serious pests of a range of crops e.g. potato, tomato and all kinds of cereal. They take two years to develop and pupate during the summer, adults eclose during July or August but remain underground in the pupal cells until the following spring. The adults ‘click’ readily when handled and are strong fliers.
A very distinctive species which is soon recognized in the field; 10-15mm and shiny, the head and pronotum are black and the elytra contrastingly dark brown. The entire upper surface is clothed with pale grey-brown pubescence. The head is transverse, densely punctured and with prominent eyes. Antennae 11-segmented; the first broad and curved, the second distinctly shorter than the third which is slightly shorter than the fourth, and segments 4-11 are weakly serrate. Pronotum convex and elongate, moderately densely punctured and
with a weak median impression that extends at least half way and often to the anterior margin. Lateral and posterior margins bordered, the hind angles extend back only slightly beyond the basal margin and lack a dorsal ridge. Scutellum large and convex at the base. Elytra parallel in the basal half and evenly narrowed to a rounded apex; each with 9 complete and punctured striae; the sixth continuing along the basal margin and forming a raised border. The interstices generally with four rows of fine punctures. Legs pale brown, often with the tibiae darker. Tarsi 5-5-5, the second and third lobed below and the fourth variously hidden within the third. Males are smaller with the pronotum less sinuate and the elytra narrower. Entirely black specimens, sometimes with a metallic green lustre, occur on the continent.