Caenocara Thomson, C.G., 1859
POLYPHAGA Emery, 1886
BOSTRICHOIDEA Latreille, 1802
PTINIDAE Latreille, 1802
DORCATOMINAE Thomson, C.G., 1859
C. affinis (Sturm, 1837)
C. bovistae (Hoffmann, J., 1803)
Caenocara affinis (Sturm, 1837)
Reported sporadically across the Palaearctic region to the far east of Russia, this species has a mostly central and southern distribution in Europe; it extends from The Pyrenees through Northern Italy to the Balkan Peninsula and Ukraine and north to Germany, Poland and Latvia. The species occurs from lowlands to middle mountain altitudes throughout the range but is sporadic, very local and generally rare. Associated with puffball fungi (Bovista Pers. (1794) and probably other terrestrial species) and occasionally swept from adjacent low vegetation or extracted from moss etc., the species has a similar biology to C. bovistae. Adults occur during the summer and disperse by flight but, beyond finding them within host material, they seem always to occur as single specimens or in small numbers. Included on the UK list from a few specimens sampled from Common Puffball (Lycoperdon perlatum Pers. (1796) in West Suffolk in 1917.
Very similar in size and habitus to C. bovistae, with which it is often confused on the continent, but more evenly convex and shinier in appearance. The main differences are in the elytral pubescence and the form of the maxillary palps. In bovistae the elytral pubescence is entirely short and recumbent whereas in the present species it consists of short recumbent pubescence as well as longer sub-erect hairs. The terminal maxillary palpomere is much broader than in bovistae, greatly expanded from near the base and sinuate and rounded at the apex.
Caenocara bovistae 1
Caenocara bovistae 2
© Lech Borowiec
Caenocara bovistae (Hoffmann, J., 1803)
This species occurs across the entire Northern Palaearctic region from Europe to Siberia, Mongolia and the far east of Russia; in Europe it occurs from lowlands to middle mountain altitudes from the Pyrenees through Northern Italy to Romania and Ukraine and north to the UK, Denmark and the all Baltic countries into northern provinces of Fennoscandia. Throughout most of this range it is very local and scarce, more especially so in northern regions. In the UK it is very local and rare; it was formerly more widespread, occurring in north western England, but is now more or less restricted to a few sites in central and south eastern England and Wales, where it is mostly coastal. Adults have been recorded throughout the year but they are generally active from May until September or October, peaking in abundance during June and September. The species is associated with various terrestrial fungi, mostly puffball and earthballs, (species of Bovista Pers. (1794), Scleroderma Pers. and Calvatia Fr. (1849), but adults occasionally occur in other fungi and are sometimes found among decaying moss or litter near to their fungal hosts. The usual habitat is open grassland on light or free-draining soils, often in disturbed or grazed areas, and in Northern Europe they sometimes occur in clearings in extensive conifer plantations. Mating occurs in the summer, it is likely that this occurs within sporocarps and that at least some adults remain after females have laid eggs because they have been recorded in this habitat through the winter. Larvae develop among host tissue, overwintering and pupating in situ during the spring. Teneral adults have been recorded from May until July, they are mostly nocturnal, leaving the host fungi and wandering into adjacent areas or dispersing by flight, but they seem not to be attracted to light and they rarely occur in flight-interception traps. The best way to find the species is to collect suitable fungi in the spring and keep it under suitable conditions until the summer in the hope of finding emerged adults.
1.5-2.5 mm. Strongly rounded and very convex although a little flattened above, body finely punctured and pubescent, shiny black or with a slight blue tinge, appendages pale brown. Head small and hypognathous, broadest across strongly convex eyes that are deeply incised anteriorly, vertex weakly convex and frons flat between the eyes. Terminal maxillary palpomere smoothly narrowed from the base to a sharp and slightly curved apex. Antennae 9-segmented; basal segment curved and widely expanded internally, second segment broadest across the base and almost triangular, 3-5 transverse and 6-8 form an elongate and very distinctive club. The sexes may be determined by the form of the seventh antennomere; pectinate in males, strongly serrate in females. Pronotum widely transverse, broadest across acute posterior angles and narrowed to a smoothly rounded (from above) apical margin, basal margin strongly sinuate and produced medially. Scutellum small but obvious, broadest across the base, curved laterally and produced to a fine point. Elytra smoothly rounded and continuous in outline with the pronotum, surface deeply impressed inside a distinct subhumeral elevation, randomly punctured throughout although these often form partial striae towards the base, the punctures mostly fine but tending to be larger in the basal half where the cuticle is finely rugose, at least in places, pubescence short and entirely recumbent. Legs long and slender with all femora and tibiae of more or less equal width and length. Tarsi 5-segmented, the basal segment elongate and slender, 2-4 bilobed and the terminal segment small and globose. Claws small, very fine and without, or with a very slight, basal tooth.