Longitarsus dorsalis (Fabricius, 1781)       Notable B
Widespread but very local throughout southeast England including the Isle of Wight, west to Dorset and Gloucestershire and north to the Humber, with an old record from mid Yorkshire (NBN). Associated with Senecio spp.; Groundsel (S.vulgaris), Ragwort (S.jacobaea) and Marsh Ragwort (S.aquaticus), and also occasionally on other Asteraceae including some cultivated species e.g. Oxeye daisy (Leucanthemum vulgare), Sunflower (Helianthus) and Goldenrod (Solidago virgaurea), generally on chalky or sandy soils including coastal areas. Adults overwinter and have been observed from march to june and september and december (Hyman and Parsons), from Watford we have records from february, april and august. Larvae develop within the roots of the host and fully developed specimens have been observed in late august and september, pupae have been found during late september and early october (Newton, 1933). Adults are macropterous or brachypterous and able to fly (Shute, 1980). Our few local records are spread around Watford; Radlett road, Cassiobury park and Tesco's car park, each from S.vulgaris which is widespread and common, and each time from maintained areas with heavy human traffic.

2-3mm. One of the few longitarsus species which can be identified with confidence; its distinctive yellow margined elytra and small size are recognisable with a lens even in the field. Head, appendages and underside black. Head somewhat shining, densely microsculptured and with a group of punctures beside eyes. Pronotum yellow with various darker marks, generally at least by front margin, finely bordered laterally and basally, with strong isodiametric microsculpture and fine puncturation. Elytra strongly shouldered, puncturation stronger than on pronotum, microsculpture less distinct so that they appear more shining than head and pronotum, outer third to half, including epipleurs, bright yellow. Epipleurs strongly narrowed apically from middle. Upper surface of hind tibiae flat, with broad flat setae on outer side and with a short pale terminal spur on inner side. First segment of hind tarsus as long as remainder combined (diagnostic for Longitarsus).

Description from 2 Watford specimens at X40

References

Newton, H.C.F., 1933 On the biology of some species of Longitarsus living on Ragwort. Bulletin of entomoligical research. 24:511-520.
Shute, S.L., 1980. Wing polymorphism in British species of Longitarsus Beetles. Systematic Entomology. 5:437-448.


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