Dryops ernesti Gozis, 1886

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POLYPHAGA Emery, 1886

BYRRHOIDEA Latreille, 1804

DRYOPIDAE Billberg, 1820 (1817)

Dryops Olivier, 1791

This western Palaearctic species is widespread across central and northern Europe from the Pyrenees to central Italy, Bulgaria and Greece, extending north to the UK and Denmark and reaching some northern provinces of Fennoscandia. The species is generally common throughout this range and occurs from lowlands to about 2000 m in mountainous regions. In the UK it is locally common throughout England, Wales and Scotland north to Inverness, there are scattered records further north and in central Ireland, and it is known from IOW, Anglesey and some of the Western Isles but from Man The typical habitat is still or slow-moving water margins with patchy vegetation where adults usually occur under debris or among wet moss although at higher altitudes they often occur in permanently damp meadows and river valleys. Adults are present year-round, they overwinter out of water and are active from March until September, peaking in abundance during May and June. They rarely occur away from water and spend most of their time concealed among the substrate etc. although they do crawl on the surface during the warmest days, they are known to be herbivores though in some works they are also quoted as being carnivores. Adults do not swim and when immersed they trap a conspicuous plastron; they crawl slowly over the substrate but sooner or later float to the surface via the buoyancy of the trapped air. Eggs are deposited into marginal plant stems using the rigid ovipositor. Larvae have been found through the summer in much the same habitats as the adults, they can survive immersion but they have functional spiracles and lack gills, they are not predacious but consume decaying plant material in wet soil and leaf-litter, sometimes in waterlogged soils. On the continent they have also been found feeding at the roots of corn etc. in arable situations. Pupation always occurs among substrate away from water. Adults can be sampled by sieving marginal soil etc., they often occur in winter extraction samples and, at least during the warmer months, usually occur in numbers. The species is fully-winged but seems to fly only rarely.

Dryops ernesti

Dryops ernesti

© Lech Borowiec

3.8-4.5 mm. Elongate-oval and discontinuous in outline, shiny dark brown to dark grey, sometimes almost black, antennae dark with a pale brown club, legs dark with paler tarsi. Dorsal surface with long semi-erect hairs among a dense shorter pubescence. Head slightly narrower than the anterior pronotal margin, convex towards the base but flattened between round, convex and finely-pubescent eyes, surface moderately strongly but not densely punctured. Antennae 9-segmented, second segment dilated and broadly rounded internally and 3-9 closely adpressed and progressively narrowed to a rounded apical segment. Pronotum transverse, broadest towards the base and narrowed to projecting anterior angles, posterior angles produced and basal margin flat behind the scutellum then strongly sinuate towards the angles. Surface evenly convex across the disc or, rarely, with a slight median longitudinal ridge, and with a sinuate longitudinal impression towards each lateral margin. Pronotal punctation consists of extremely fine punctures between larger punctures which are closer than those on the elytra and on average separated by less than a puncture width. Elytra parallel-sided or slightly dilated from angles shoulders to a continuous apical margin, surface evenly convex and randomly punctured although these may form partial striae near the base, these are about the same size as those on the pronotum but obviously more widely separated. Legs long and narrow, femora and tibiae pubescent, tarsi glabrous. Tibiae parallel-sided or only very slightly broadened from the base, without external spines or obvious terminal spurs. Tarsi 5-segmented, the basal segments short and unmodified and the terminal segment long and curved. Claws large and robust, smooth internally and without a basal tooth.