Crepidodera Chevrolat in Dejean, 1836
Represented by more than 30 species across the Holarctic region, this genus is otherwise absent from much of the Old World with only a single species known from the Oriental region, 16 species are known from North America and of the 15 or so Palaearctic species, 9 occur in Europe. Beyond this the Neotropical region is diverse with at present about 15 described species although this is likely to increase, and at least 15 species have been described from the Oceanic Islands. In total about 80 species are known although the Neotropical fauna needs to be revised as some may be wrongly assigned to the genus. With the exception of Crepidodera nitidula (Linnaeus, 1758), which is a mostly Central and Northern European species, our UK species are generally widespread across Europe and Asia, but the Palaearctic species are otherwise predominantly western or eastern in distribution. Of the European species, C. aureaola (Foudras, 1860) is restricted to France and the Iberian peninsula, C. nigricoxis Allard, 1878 has a patchy south eastern distribution and is also known from the Far East, and C. peloponnesiaca (Heikertinger, 1910) id endemic to Greece, the rest being widespread. Other restricted species include C. wittmeri (Douget, 1976) from Iran, C. gemmata (Abeille, 1895) from Algeria and Tunisia and C. ussuriensis Konstantinov, 1996 which is known only from the type locality in the far east of Russia.
Nomenclature in older works can be confusing; the species were formerly included in Chalcoides Foudras, 1860 while Crepidodera included species now assigned to Neocrepidodera Heikertinger, 1911, but our species are very distinctive and so identification should be straightforward. All are small, 2.3-4.1 mm in length, and brightly metallic, being either unicoloured or bicoloured with the forebody and elytra strongly contrasting. All have narrow, triangular and well-defined frontal furrows, a deep transverse basal furrow delimited by short longitudinal grooves on the pronotum, punctured elytral striae and enlarged hind femora. These characters are sufficient to identify the genus, and our species may be identified as follows:
Apical elytral angles with a small tooth, punctured elytral striae confused towards the base and often across the disc.
Apical elytral angles without a tooth, elytral striae regular.
Antennae abruptly bicoloured; segments 1-4 pale orange or yellow, 5-11 black or dark brown.
Antennae gradually darkened towards the apex or entirely pale.
Dorsal surface bicoloured; pronotum red, coppery or pale golden, elytra bright green or reddish-green.
Body unicoloured, from bright green to dark blue, often with contrasting metallic overtones.
Pronotum strongly transverse, at least 1.6X wider then long, with fine and shallow punctures, and almost straight lateral margins in the basal half.
Pronotum less strongly transverse, about 1.5X wider than long, deeply and strongly punctured across the disc, and slightly sinuate laterally towards the base.
Adults occur year round, they overwinter in tussocks or under bark and are active over a long season from early spring. Host plants include various Salicaceae mostly willows and poplars but adults of most species feed on leaves of a wide range of trees and shrubs and so may be encountered through general beating and sweeping. Some species may also occur in numbers on blossom in the spring. Mating occurs in spring and eggs are laid on host foliage during spring and early summer, larvae drop to the ground and burrow down to roots on which they will feed. Pupation occurs underground during the summer and new-generation adults appear from July or August. So far as is known all our species are univoltine.