Sulcacis nitidus (Fabricius, 1792)
More generally referred to in the literature as S. affinis (Gyllenhal, 1827) or Ennearthron affinis (or ‘affine’ in Joy). This species is widespread across the Palaearctic region, extending into eastern Siberia, it is generally common and often abundant throughout Europe although sporadic in the north e.g. it is rare and known only from lowlands and lower mountain altitudes in Poland, but often abundant in Boreal forests in northern Scandinavia. In the UK it is common across south-east England below London but otherwise scattered and very local further north to Cheshire. Adults are present year-round, they are active from very early in the year and peak in abundance during spring and autumn, they are known to be long-lived, about seven months, and breed over a long season from early spring, typical habitats are open woodland and wooded parkland but they may also occur on individual trees in hedgerows etc. Adults might occur on a range of fungi but larvae usually develop in various species of Trametes Fr, (1838) and adults will probably always use this host if it is available, those from which adults have been reared include T. versicolor (L.)Lloyd (1920), T. trogii Berk. 1850, T. pubescens (Schumach) Pilát (1939), T. ochracea (Pers.) Gilb. & Ryvarden, T. hirsuta (Wulfen) Lloyd (1924) and T. gibbosa (Pers.) Fr. (1836). On the continent they have also been reared from a wider range of host species but it is not known whether Trametes was also available, these include Pycnoporus cinnabarinus (Jacq.) P. Karst (1881), Fomitopsis betulina (Bull.) Cui, Han & Dai (2016), Lenzites betulina (L.) Fr., (1838), Hapalopilus nidulans (Fr.) P.Karst (1881), Cerrena unicolor (Bull.) Murrill (1903) and Bjerkandera adusta (Willd) P. Karst. (1880). Adults are active at night and might be found on or about fruiting bodies, they may be obtained at any time by tapping likely samples over a tray or taking samples for extraction; it does not seem to matter how old or what state the fungus is in e.g. Trametes versicolor is an annual species but the beetle will continue to use it as host material long after it has died, and often until it has been completely consumed, older but substantially intact brackets will often be found to host all life stages of the beetle and adults often mate and oviposit repeatedly over a long season from early in the year. The very best way to obtain adults is to take likely bracket samples and rear out the adults as in this way not only can host associations be noted but a range of other species is also likely to appear.
Sulcacis nitidus 1
© Lech Borowiec
Sulcacis nitidus 2
1.2-1.4 mm. Long-oval and parallel-sided; entirely black or very dark brown with pale appendages and a dark antennal club, pronotum duller than the elytra due to stronger microsculpture. Pronotum and elytra with fine erect scales, those on the elytra longer, more conspicuous and often arranged in irregular longitudinal rows. One of only two UK ciids with 9-segmented antennae (see Ennearthron cornutum (Gyllenhal, 1827) below). Head transverse, hypognathous and only narrowly visible from above, weakly convex between protruding convex eyes and with conspicuous golden pubescence, clypeus with two sharp tubercles in the male. Antennae inserted laterally in front of the eyes; basal two segments broad and globular, third segment about as long as the next three, fourth quadrate, fifth and sixth short and transverse and seven to nine form a loose club. Pronotum transverse, broadest behind the middle and curved anteriorly (from above), posterior angles rounded and basal margin almost straight, surface evenly convex, finely punctured and distinctly microsculptured throughout. Elytra with finely rounded shoulders and a continuous apical margin, finely and randomly punctured throughout, microsculpture weaker and less distinct than that on the pronotum. Tibiae simple, the front tibiae not produced into an apical tooth but rounded and with short stiff setae at the outer apical margin. Tarsi 4-segmented (they usually appear 3-segmented), the long terminal segment as long as the others combined. Claws smooth and weakly toothed at the base.