Ptinus sexpunctatus Panzer, 1792
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POLYPHAGA Emery, 1886
BOSTRICHOIDEA Latreille, 1802
PTININAE Latreille, 1802
PTININI Latreille, 1802
PTINUS Linnaeus, 1767
This is a native Palaearctic species occurring sporadically throughout Europe north to Scandinavia and east to Siberia; in the U.K. it is locally common through Wales and southern England. First recorded in North America in 2003, it is now widespread, although rare, in the United States and Canada and is thought to have been accidentally introduced along with solitary bees imported as pollinators. In Europe it is associated with various hymenoptera; both social bees as well as solitary species e.g. members of the genera Osmia, Anthophora and Megachile, and it has been found in association with Hoplitus adunca (Panzer) and Chelostoma nigricorne (Nylander). Adults feed on detritus and dead insects and probably bee larvae and pupae while the larvae consume pollen and nest detritus and have also been observed in nests of the saproxylic ant Lasius fuliginosus (Latreille) as well as in avian nests. The natural habitat is wooded pasture and broadleaf woodland where they occur under the bark and among decaying wood of a range of species. On the continent they have been found in old Cerambyx galleries in oak. Adults may occasionally be seen basking in hot sun on denuded trunks but they are generally nocturnal and come readily to light; they are partly synanthropic, probably alongside their hymenopteran hosts, and so occasionally occur in houses etc. Locally we have recorded them on beech stumps during the day and on a range of trees at night, generally as single specimens although from early June to mid-July 2014 they were present in large numbers (>100) on the metal railings of a footbridge over the river Gade in Cassiobury Park, we assumed these to be from a series of large willow trees containing plenty of decaying wood which overhanging the river. In northern Europe they are associated with a range of deciduous trees as well as pine. The adults fly readily and occur in flight interception traps as well as in moth traps.
2.0-4.5mm. This distinctly marked beetle should not be confused with any other species on the British list. The entire body varies from light to dark brown, sometimes with the elytra a little darker. The head is not normally visible from above, it is covered with elongate pale scales and the eyes are convex and prominent. The antennae are filiform, slender and densely pubescent; the segments are longer and more robust in the male. Pronotum convex, constricted before the base and raised either side of the disc, pubescence erect and pale to dark brown. The scutellum is covered with dense pale pubescence. Elytra parallel or a little widened towards the apex, with deeply impressed and punctured striae, each puncture with a tiny recumbent seta; the interstices are convex with longer, erect setae. Each elytron with a subapical patch and two transverse bands of elongate pale scales, one towards the base and one behind the middle; these are usually well defined but sometimes fragmented, especially the basal marking which may be split to form several discreet markings or may extend onto the shoulder or along the lateral margin. The underside of the thorax and abdomen is covered with fine pale pubescence. The legs are robust and entirely covered with dense pale pubescence. Tarsi 5,5,5, without and bilobed segments.