Anoplus plantaris (Naezen, 1794)
POLYPHAGA Emery, 1886
CURCULIONOIDEA Latreille, 1802
CURCULIONINAE Latreille, 1802
ANOPLINI Bedel, 1883
ANOPLUS Germar, 1820
This is the most common member of the genus, it widespread and locally common from lowland to mountain altitudes across central and northern Europe, extending to the far north of Fennoscandia and east through Russia and Siberia, in the UK it is common across England and Wales though scarce in the West Country, more local in the north and there are a few records from the Scottish Highlands and Northern Ireland. Adults are present from April until late in the year and occur on birches; Silver birch, B. pendula, and downy birch, B. pubescens, as well as various hybrids, and on the continent they also occur on alder, Alnus glutinosa. Typical habitats are wherever the hosts occur, woodland and wooded parkland, heaths and moorland etc, and adults will usually be found in numbers. Mating occurs early in the year and oviposition begins in early May, eggs a single egg is laid on the underside of a developing leaf, usually near to the central vein in the distal half where the larva will begin to mine, affected leaves are usually much broader than others and it is thought that secretions from the female during oviposition retard the longitudinal expansion of the leaf. The larva enters the leaf at the oviposition scar which may become swollen and resemble a gall, it mines towards the leaf margin and then the mine usually loops around the edges, often isolating areas of leaf which then die-off, mines are translucent, they penetrate to both surfaces and have a thin dark central line of frass throughout their lengths. Larvae are fully-grown by June when they cut out an area of leaf around the end of the mine, this will fall to the ground and the larva will pupate within. New generation adults occur from June or July, these will go on to overwinter and there is only a single generation each year. Adults may be beaten or swept from host foliage during the season and may be found among litter around the base of host trees during the winter.
1.7-2.2mm. Entirely black with the legs dark brown and the antennal scapes yellow. Readily identified by the 3-segmented tarsi. Head transverse with weakly convex eyes and short diverging temples, vertex strongly punctured, clypeus and rostrum more sparsely so, rostrum short and broad with lateral scapes visible from above towards the apex. Antennae geniculate, scape rather abruptly thickened towards the apex, funiculus 7-segmented, club broadly-oval. Pronotum transverse, broadest in the basal third and narrowed to a straight apical margin, basal margin sinuate medially, surface strongly punctured and shiny, lacking microsculpture. Elytra shiny black, broadest in the apical half and weakly constricted before a continuously rounded apex, striae deeply impressed and indistinctly punctured, interstices convex, finely rugose and each with a more-or-less regular row of pale semi-erect setae. Femora unarmed, middle and hind tibiae unarmed, front tibiae with a small incurved spur at the apex.