SPHINDIDAE Jacquelin du Val, 1860

Dry-Fungus Beetles

Includes two small fungivorous species, generally very local and rare but sometimes found among wood or by sweeping vegetation.

POLYPHAGA Emery, 1886

CUCUJOIDEA Latreille, 1802

Sphindus Dejean, 1821

Aspidiphorus Dejean, 1821

1.2-2mm

Suborder:

Superfamily:

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Size:

Around the World

Sphindidae is a small family of about 70 species in 9 genera and 4 subfamilies. The group has a worldwide distribution but is only poorly represented in northern temperate regions; 4 species of 2 genera occur in central Europe while 9 species of 4 genera occur in the United States. Odontospindinae Sen Gupta & Crowson, 1979 includes 3 species of the single genus Odontosphindus LeConte, 1878, 2 occur in the Nearctic region while O. grandis (Hampe, 1861) is widespread in south east Europe. Protosphindinae Sen Gupta & Crowson, 1979 includes 2 species of the Chilean endemic genus Protosphindus Sen Gupta & Crowson, 1979. Sphindiphorinae McHugh, 1993 is monotypic, Sphindiphorus natalensis Sen Gupta & Crowson, 1979 being endemic to Natal. Sphindinae Jacquelin du Val, 1860 includes 6 genera, Nipponaspidiphorus Miwa, 1933 being invalid. Notosphindus McHugh & Wheeler, 1991 includes a single species from Tasmania. Eurysphindus LeConte, 1878 includes 7 species distributed throughout the New World while the 7 species of Carinisphindus McHugh, 1990 are more or less restricted to Central America; Florida, Panama and 5 are endemic to various Caribbean islands. Genisphindus McHugh, 1993 includes 5 species from Central and South America of which G. rotundus McHugh, 1993 is endemic to Trinidad. Sphindus Dejean, 1821 includes 15 species and is Holarctic and also with single species endemic to Sumatra, Cuba and Madagascar, the type species, S. dubius (Gyllenhal, 1808) occurs throughout Europe as well as Algeria and the Canary Islands and extends north into the U.K. Aspidiphorus Dejean, 1821 is the largest genus with about 20 species and is widely distributed through the Old World although most species are localized and several are endemic to various regions e.g. Seychelles, South Australia, Tasmania and Lord Howe Islands. Three species occur in Europe of which one, A. orbiculatus (Gyllenhal, 1808) extends north to the U.K.

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.

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.

UK Species
Sphindus dubius
Aspidiphorus orbiculatus

A widespread species occurring locally throughout Europe and parts of North Africa and extending east to Ukraine, in the U.K. it is a very local species of England and Wales as far north as South Yorkshire. Adults appear from July to September in wooded areas with plenty of decaying wood etc. for their host fungi. Adults are small, 1.8-2.0mm, elongate and sub-parallel, shiny dark brown with narrowly pale pronotal margins and lighter areas to the elytra, typically over the shoulders and before the apex. Head transverse with prominent and convex eyes, a distinct frontoclypeal suture and transverse labrum that is curved anteriorly. Antennae 10-segmented, 2 basal segments expanded internally, 3 elongate, 4-7 quadrate to transverse, 8 strongly transverse, 9 weakly transverse and wider than 8, and the terminal segment long, broad and pointed. Pronotum smoothly convex, strongly and quite densely punctured, broadest in front of distinct posterior angles and curved to a rounded anterior margin. The basal margin is only weakly sinuate and the lateral margins are finely crenulate. Scutellum large and rounded from the base. Elytra with strongly punctured striae from the base to the apex and finely and diffusely punctured interstices. Meta-tarsi 4-segmented in the male, 5-segmented in the female, all tarsal segments narrow, without lobes, the terminal segment as long as the others combined.

This widespread European species occurs throughout England and Wales, although seems to be largely absent from the West Country, and there are a few scattered records from the Scottish Highlands. Adults occur year-round, during the winter under bark or among fruiting bodies and in the spring and summer among vegetation as they disperse. In South Herts we have found adults under Daldinia on Fraxinus during December. Adults are convex and broadly-oval, usually entirely brown and finely pubescent. 1.2-1.8mm The antennae are distinctive; 10-segmented with the 2 basal segments asymmetrically enlarged from near the base, 3 and 4 elongate, 5-7 transverse and 8-10 form an elongate club, the terminal segment being pointed at the apex. Pronotum broadest at the base and narrowed to rounded anterior angles, surface smoothly convex and finely punctured although more strongly so than those on the elytral interstices, the basal margin strongly sinuate and produced backwards medially. Scutellum transverse and rounded from a flat base. Elytra with strongly punctured striae complete to the apex and a scutellary striole that may extend to the middle. Legs long and slender with tibiae characteristically broadened from the basal third and curved or angled externally.  Legs pale, antennae pale with the club dark, in some specimens the body may be variously pale, especially the pronotal and elytral margins and diffuse areas to the elytra.

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