Tritoma bipustulata Fabricius, 1775
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
EROTYLINAE Latreille, 1802
TRITOMINI Curtis, 1834
TRITOMA Fabricius, 1775
This is a very widespread and sometimes locally common species throughout Europe from Portugal east to Greece, and from the Mediterranean north to the UK and central Fennoscandia, the wider Palaearctic distribution extends through Asia Minor, Ukraine and Russia to central Siberia. While it is generally a lowland species it occurs, unusually for an erotylid, to mid-mountain altitudes in parts of this continental range. In the UK it occurs sporadically through England north to Cumbria although it appears to be absent from the West Country. There is a single record from south Wales and it is absent from Ireland (2015). Fowler considered the species as ‘generally rare though not uncommon in some localities including the London district’ and it now has the conservation status of Nationally Scarce. Typical habitats are established deciduous woodland, wooded parkland with mature trees in various stages of decay and ancient trees on pasture. Adults are active during the day and may be found on trunks and fallen timber in the vicinity if various fungi, searching among decaying wood in rot-holes or in accumulated debris near fruiting bodies is also a good way to find them. Larvae develop among debris under bark or within fruiting bodies, in the UK it is mostly associated with Trametes versicolor (L. ex Fr.), especially when this is fruiting on Beech or oak, but on the continent it has been recorded developing in a range of fungi including Polyporus squamosus (Huds.) Fr., P. brumalis (Pers. Ex Fr.) Fr, Cerrena unicolor (Bull. Ex Fr.) Murr., Lenzites betulina (L. ex Fr.) Fr., Trametes hirsute (Wulf. Ex Fr.) Pil.. T. pubescens ( Schum. Ex Fr.) Pil. and Funalia trogii (Berk.) Bondartseve & Singer. Adults are present throughout the year, they overwinter among decaying wood or under bark and are active from February until August or September, peaking in abundance during March and again in June.
Adults might casually be mistaken for a ladybird but are readily distinguished by the form of the tarsi and the striate elytra. 3-4mm. Elongate-oval, virtually continuous in outline and broadest about the middle. Glabrous, shiny black with a large red humeral macula which extends back towards the middle of the elytra and in to the second interstice some way behind the scutellum. Head transverse, evenly convex and very finely punctured, eyes circular and weakly protruding, antennae 11-segmented and inserted under the anterior margin in front of the eyes; third segment longer than the others, 9-11 forming an abrupt club, red with the club darker. Pronotum transverse, widest at the base and smoothly rounded to indistinct anterior angles, posterior angles acute and basal margin sinuate medially, surface finely and sparsely punctured and very finely microsculptured. Scutellum large, triangular and dark, as the surrounding cuticle. Elytra with eight distinct and punctured striae complete almost to the apex, interstices flat, each with several rather randomly arranged rows of fine punctures. Legs short and robust; black with pale tarsi Femora only narrowly visible from above, tibiae strongly broadened to truncate apices and without any obvious spurs. . Tarsi 5-segmented but appearing 4-segmented as the tiny fourth segment is enclosed within the expanded third segment, terminal segment long and curved, claws curved and smooth, without a basal tooth.