Tilloidea unifasciata (Fabricius, 1787)

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POLYPHAGA Emery, 1886

CLEROIDEA Latreille, 1802

CLERIDAE Latreille, 1802

TILLINAE Fischer von Waldheim, 1813

Tilloidea Laporte, 1833

Formerly included in the genus Tillus Olivier, 1790, this species occurs throughout Europe; it is locally common in warmer regions of Central and Southern Europe but generally very local and rare in the north where it is included in many national lists from historic records, it is present on most of the Mediterranean islands and has been recorded from Turkey, Iran and India. The species no longer occurs in the UK; it is included in our list on the basis of a few specimens taken in South-East England during the 19C and was last recorded in 1877 from Surrey. In Europe the species occurs from lowlands to middle mountain altitudes, it is mainly associated with mature oaks in areas of open woodland exposed to the sun but it also occurs on other broadleaf trees and, in some southern regions it is often associated with grapevines. Adults occur from May until July or August; they are diurnal as well as nocturnal, during the day they spend most of their time on denuded areas of trunks exposed to the sun while during the warmest periods they will fly to visit a range of flowering trees and shrubs, particularly hawthorn (Crataegus monogyna Jacq.) At night they roam about the surface of trunks and fallen timber. Mating occurs at night and females search exposed wood for suitable oviposition sites. Eggs are laid in the burrows of other wood-boring beetles (particularly those of bostrichids, which might suggest an association with Psoa viennensis Herbst, 1797) on vines) and the predatory larvae move between burrows or search under bark for prey. Larvae overwinter and pupate in situ during the spring and adults emerge during warmer spells in late spring. Adults are also predatory; they hunt for other insects on wood or flowers but have also been observed feeding on pollen, they usually occur in small numbers but during the warmest spells they occasionally swarm about the top of dead stumps or trunks.

Tilloidea unifasciata 1

Tilloidea unifasciata 1

Tilloidea unifasciata 2

Tilloidea unifasciata 2

© U.Schmidt

4.0-8.0 mm. Easily recognized by the colour and general habitus and very unlikely to be confused with any other UK species. Head, pronotum and appendages shiny black, elytra black with the basal third or so red and a transverse pale creamy band behind the middle. Body with long outstanding pubescence; mostly dark on the head and pronotum but variable and often extensively pale on the elytra. Head hypognathous; broadest across weakly convex eyes and smoothly convex and finely punctured above. Antennae long, basal segments narrow, 4-10 strongly serrate and the terminal segment asymmetric and pointed. Pronotum broad and near-parallel sided anteriorly and strongly narrowed behind the middle to obtuse posterior angles, basal margin very finely bordered, surface widely uneven but without well-defined depressions or fovea, finely punctured throughout; these often forming incomplete arcuate patterns on the disc. Scutellum dark; broadest across the base and almost parallel-sided before a truncate apex. Elytra elongate, about 2:1; variable in shape but usually parallel-sided in the basal third and dilated behind the middle, with strong and deeply punctured striae from the basal margin to the base of the pale transverse band, then fading to the apex. Legs long and slender all femora of similar width and tibiae only slightly broadened from the base. Tarsi 5-segmented; basal segment elongate, 2-4 strongly bilobed and the terminal segment long and expanded from the base. Claws usually yellow, contrasting with the dark tarsi, each with a strong basal tooth and long internal lobe lying parallel with the apical half.