Athous bicolor (Goeze, 1777)
POLYPHAGA Emery, 1886
ELATEROIDEA Leach, 1815
DENTICOLLINAE Stein & Weise, 1877
DENTICOLLINI Stein & Weise, 1877
Athous Eschscholtz, 1829
Orthathous Reitter, 1905
This mostly southern and central European species occurs sporadically from Spain to Russia and Ukraine, extending north to the UK and south to Italy, Yugoslavia and Romania; it tends to be sporadic and rare in many northern regions but the UK seems to be an exception as it is locally common across Wales and the south of England. Adults are active from May until July or August, generally on fairly dry grassland but especially on hillsides exposed to the sun or near wooded borders and in clearings, they frequent various flowers in hot weather, especially umbels, or may shelter among foliage, often on Salix and Quercus, and they tend to turn up regularly in sweeping samples from such situations. Males fly during the evening until dusk while females tend to remain hidden among grass stems and flowers or under logs etc. Mating occurs through June and females deposit eggs into the soil around tussocks or herbaceous plants. Larvae develop through the summer feeding on a wide range of roots, they overwinter deep in the soil and resume feeding in the spring, pupation occurs in March or April and new-generation adults appear from June. Adults will be found by general sweeping but shaking umbel flowers into a bag during hot spells is the best way to find both sexes, males may also occur at light or in flight-interception traps.
8-10mm, females may reach 12mm. A very distinctive species that should soon become familiar, even in the field; entire dorsal surface finely and densely pubescent; head, pronotum and scutellum dark reddish-brown, elytra and appendages pale brown. Most specimens have pale elytra but these are otherwise very variable; either with the suture and lateral margins dark or extensively dark with the humeri and apical area pale, and the striae are often darkened, Head transverse, with large convex eyes that occupy most of the lateral margin, and a prominent ridge around the anterior margin, the surface densely and rather strongly punctured. Antennae long and slender; reaching back well beyond the pronotal base, the fourth antennomere about 1.75X longer than the third. Pronotum elongate; widest across the base and narrowing to prominent and slightly divergent anterior angles, apical margin
Athous bicolor 1
Athous bicolor 2
Athous bicolor 3
curved forwards, basal margin sinuate, posterior angles weakly produced back, divergent and lacking a dorsal ridge. Pronotal surface densely and quite strongly punctured; typically dark brown but often with the margins or angles to a varying extent pale. Scutellum concave across the base, approximately triangular and leaving a space around the base of the elytra. Elytra very long; about 2.5X the pronotal length, distinctly wider across the base than the pronotal base and sub-parallel to the apical third which is smoothly narrowed to a continuously rounded apical margin. Striae impressed and strongly punctured to the apex, interstices flat across the base but becoming convex towards the apex, finely punctured and densely rugose. Legs long and slender, femora unarmed and broadly visible from above, mid- and hind tibiae straight, front tibiae sinuate. Tarsi 5-segmented; the fourth segment small and fully exposed, not obscured by the third.