Otiorhynchus morio (Fabricius, 1781)
A western Palaearctic species restricted mostly to upland and mountain regions of Europe from the Pyrenees to the Carpathian mountains in Serbia and Romania and north as far as Denmark, it is very local and sporadic but often common where it occurs, the nominal sub-species occurs throughout this range, there are four others in Spain and France, and another in Portugal, it is included in the UK list on the strength of several specimens recorded from the west of Scotland prior to 1840 and a further single specimen from the far north of Scotland from 1901, but it is now presumed to be extinct here. Adults are active from May until August, they are flightless and nocturnal and prefer wet or permanently damp habitats such as the margins of mountain streams, forest margins and glades and grassland with mixed herbaceous plants. Adults are polyphagous and consume the foliage of a wide range of both woody and herbaceous plants; in many mountain regions they often occur on sorrels (Rumex spp.), butterburs (Petasites spp.), Mat grass (Nardus stricta L.), orange hawkbit (Pilosella aurantiaca (L.)), wolf’s bane (Arnica montana L.) and white hellebore (Veratrum album L.) and have been recorded from alder (Alnus glutinosa (L.))and bog-myrtle (Myrica gale L.) among many others. Larvae develop through the summer among roots and are thought to overwinter and pupate in the spring.
9.5-12.5mm. Entirely shiny black or sometimes with slightly paler legs and antennae, without scales and only very finely and sparsely pubescent, appearing glabrous at low magnifications. Head finely punctured between weakly convex eyes, rostrum quadrate and dilated towards the apex where the scrobes are visible from above, the surface flat and wide between raised lateral margins, antennae long and slender with segments 7 and 8 quadrate or slightly transverse and the club only a little wider than the last funicular segment and relatively short, not more than 3X longer than wide. Pronotum finely punctured throughout, becoming weakly granulated or rippled towards the lateral margins, quadrate or slightly transverse and strongly rounded laterally, more so in the male. Elytra broadest in the basal half and about 1.5X longer than wide, the striae consist of rows of weak punctures and the interstices are weakly rugose and usually have a faint net-like microsculpture. Legs long and robust with large clavate femora which lack ventral teeth, front tibiae simply rounded externally but expanded into an internal apical tooth, internal and external apical margins of the middle and hind tibiae produced into a sharp tooth.
Otiorhynchus morio 1
Otiorhynchus morio 2
Otiorhynchus morio 3
Otiorhynchus morio 4
Otiorhynchus morio 5
Similar to our other member of the subgenus, O. arcticus (Fabricius, O., 1780) which occurs in central and northern Scotland, but this species is smaller <8.0mm and has more prominent eyes. Dark legged forms of O. tenebricosus (Herbst, 1784) are similar in size and appearance but here the dorsal surface is usually more heavily sculptured, the pronotum less strongly rounded laterally and the antennae are more slender; segments 7 & 8 are distinctly elongate and the club is at least 4X as long as wide.