Description

Based on a combination of various morphological features the Sphindidae are considered to be a distinct family and traditionally have been thought to be related to various cucujoid families e.g. Silvanidae and Phloeostichidae but recent molecular studies have suggested a position independent of the cucujoid series and in a sister group to a clade including the Tenebrionoidea and Lymexyloidea. All species are convex and small, 1.5-3.5mm, they vary from elongate, almost parallel-sided and discontinuous in outline e.g. in Odontosphindus, to almost circular and continuously curved e.g. in Genisphindus, a range more-or-less encompassed by our two U.K. species. All are drab brown to dark red-brown although in some Sphindus, Carinisphindus and Notosphindus the elytra are bicoloured. All are pubescent dorsally, usually sparsely so with recumbent or semi-erect and fine setae although some Aspidiphorus are almost glabrous and Eurysphindus may have dense, erect and quite long pubescence. The head is transverse and often only narrowly visible from above, with prominent, convex eyes and 10- or 11-segmented antennae which are distinctive; pubescent and proportionally quite long with the 2 basal segments expanded internally from the basal third or half and a 2 or 3 segmented club which may be well-developed e.g. in Genisphindus. Antennae inserted laterally in front of the eyes and behind the base of the mandibles. Vertex convex, distinctly punctured and often with one or more longitudinal impressions, frontoclypeal suture distinct and curved, clypeus and labrum distinct and sometimes produced forwards, mandibles prominent and proportionally large, with apical teeth, a basal mola and a dorsal tubercle and setose cavity which is thought to act as a mycangium although adults of many species have various cavities or depressions which carry fungal spores. Maxilla with narrow lacinia and (usually) galea and 4-segmented palps which have the terminal segment narrow and cylindrical. Labial palpi 3-segmented. Pronotum quadrate to transverse; rounded and smooth or finely dentate laterally and smoothly convex, without sculpture although in many with shallow basal impressions. Prosternum broad, sometimes with various depressions for the antennae and truncate or sinuate posteriorly, coxal cavities narrowly to widely separated, transverse and open or closed behind, horizontally to obliquely orientated and sometimes produced to a point laterally. Mesosternum narrow, coxal cavities transverse and usually weakly separated. Metasternum long, convex but usually flattened across the centre and usually strongly and quite closely punctured, straight anteriorly and usually emarginate posteriorly where the first abdominal ventrite is produced forward between the transverse and generally widely separated coxal cavities. Abdomen with 5 free ventrites; all distinctly punctured and pubescent, in some with various larger punctures and/or depressions. Scutellum usually obvious and distinctly punctured. Elytra smoothly convex, without prominent shoulders and completely covering the abdomen, smoothly rounded to almost straight laterally and with narrow epipleura which do not reach the apex. Most species have strongly punctured striae that continue to the apex and an abbreviated scutellary striole, and finely punctured and pubescent interstices. Hind wings well-developed. Legs slender and generally proportionally long, all coxae transverse and variously separated, trocanters small and triangular, tibiae cylindrical and parallel-sided to flattened and curved or angled externally, without apical spurs although sometimes with a transverse row of stiff setae. Tarsi 5-5-5 in the female and 5-5-4 in the male, shorter than or as long as the tibiae, segments simple or only weakly expanded, the terminal segment often as long as the others combined. Claws smooth and without a basal tooth.

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Ecology

So far as is known all species are associated with slime mould sporocarps, both adults and larvae feed upon spores and fruiting-body tissues and all stages generally remain near to or within the host, although during dispersal adults may be found in a variety of situations, and during the winter may remain under bark or among wood debris or leaf litter. Samples of infested decaying wood or vegetation should be collected and extracted in a Berlese apparatus to obtain adults although they will occasionally occur by general sweeping in the spring and summer and many species have been taken in numbers in flight interception traps and at U.V. Several species have proved easy to rear in the laboratory on suitable myxomycete hosts. Development from egg to adult is generally rapid, 3-4 weeks, and large populations may soon build up. Females oviposit on the surface of fruiting bodies and larvae emerge after a week or so, these feed upon and within sporocarps and pass through 4 instars before securing themselves to the substrate using an anal secretion before pupation. It is not known how many generations are produced each year in temperate regions. Two species occur in the U.K.