|Luperus longicornis (Fabricius, 1781)|
Although we have not recorded this beetle from our Watford area it should not be unreasonable to expect it; the
species has a wide national distribution to the far north of Scotland and there are records from the Isle of
Wight and Anglesey (Cox). Having said that there are
some fairly wide areas without records eg through Dorset and Wiltshire, the midlands, Northumberland and southern
Scotland, unfortunately for us Hertfordshire is also generally lacking in records. Our featured specimens are from
Brockenhurst, Hants where we found them to be abundant alongside pathways through mixed coniferous/broadleaf
woodland on birch (Betula pendula) and hawthron (Crataegus monogyria) and, to a lesser extent, on
various umbels (July 2006 and June 2009). Adults are readily beaten or swept from foliage or surrounding long grass
and easily spotted on flowers. They are known to feed on birch and willow (Salix spp.) foliage and also
(perhaps) pollen, and have been recorded from a wide range of broadleaved trees. Typical habitat is damp or wetland
situations eg open woodland, moors, heaths, marshes and fens. Adults occur from March to September or October
although they may not become common until mid-May. Eggs are laid in the soil and larvae feed on grass roots during
late summer and autumn. Winter is passed in the larval stage and development is completed in the spring. Pupation
(probably) occurs in the ground during the spring (Cox).
A very distinctive species, not likely to be confused with any other.
4-5mm. Body entirely shiny black, elongate and broadest behind middle of elytra. Head very finely punctured with frontal tubercles well impressed to inner margins of eyes. Eyes entire, convex and prominent. Antennae black with segments 1-4 yellow, segment 2 very small. Proportionally very long; in male as long as the body, shorter in the female. Insertions separated by about the length of the first segment. Pronotum transverse and broadest a little in front of middle, lateral and basal margins strongly bordered, anterior margin a little less strongly. Front and hind angles with a short blunt projection. Surface convex and very finely punctured. Scutellum smooth and shiny, as pronotum. Elytra shiny but appearing less so than the head and pronotum due to random and quite strong puncturation, this becoming weaker towards the apex. Shoulders prominent, width across base wider than pronotum, lateral margins bordered, these are not visible from above due to convexity. Elytra in male narrower and more parallel sided than in female. Legs testaceous but for base of femora and last segment, and sometimes penultimate segment, of tarsi dark. Hind femora not obviously broader than mid femora. Tibiae without teeth or spines. Basal segment of hind tarsi as long as the next two together. Claws short and curved, each with a long tooth on inner side.
Description from 4 Hants specimens at X20
Three species of Luperus are keyed in both Joy and Fowler. One of these has now been transferred to another genus and is now known as Calomicrus circumfusus (Marsham, 1802), this is Luperus circumfusus Marsham in Joy and L.nigrofasciatus Goeze in Fowler (who gives the subgenus Calomicrus).
All three species are readily identified among the British Chrysomelidae by the following combination of characters: Antennae inserted on forehead, their insertions about the length of the basal apart, eyes entire, pronotum bordered, elytra elongate and randomly punctured and hind femora not dilated. L.longicornis will give a good idea of the general form.
Our three species key readily on external morphology. (The following is a combination of characters from Fowler and Joy).
1. Second antennal segment as long as, or nearly as long as, third segment. Eyes less prominent. Elytra with sparse, erect pubescence on apical half. Yellow with head, base of pronotum and area around suture black. 3-4mm. On dwarf gorse.
Calomicrus circumfusus (Marsham)
22. Pronotum black. 4.0-5.0mm.
Luperus longicornis (Fabricius)-- Pronotum pale; yellow to reddish yellow. 3.5-5mm.
Luperus flavipes (Linnaeus)