DASYTIDAE Laporte, 1840

Soft-Winged Flower Beetles

Includes several widespread and common species which can be found by sweeping flowers in spring and early summer, most have a short season.

POLYPHAGA Emery, 1886

CLEROIDEA Latreille, 1802

2

4

9

3-7mm

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Introduction

Often listed as a subfamily of a much more broadly-defined Melyridae Leach, 1815 along with Melyrinae Leach, 1815, Malachiinae Fleming, 1821, Rhadalinae LeConte, 1840 and Gietellinae Constantin & Menier, 1987, the group is now generally accepted as a distinct family of about 1000 species in 75 genera and 6 subfamilies. The greatest diversity is in northern temperate region and in general the group is relatively poorly represented in tropical areas.

  • CHAETOMALACHIINAE MAJER, 1987 includes 14 genera, more than 150 species and occurs across temperate western and central Palaearctic areas although in Europe it is present only in the south and southeast, extending south into tropical Africa and the Oriental region.

  • GIETELLINAE Constantin & Menier, 1987 includes 2 species of the single genus Gietella Constantin & Menier, 1987 from south-western Europe. They are atypical, rather ant-like in appearance with a narrow forebody and rounded and convex elongate elytra and narrow appendages.

  • RHADALINAE LeConte, 1840 A large group of 18 genera and about 350 species, it is represented in all regions except for Australasia and most regions are only poorly represented; 4 species of 3 genera are Nearctic, and the African fauna includes 2 species of 2 genera. The Neotropical fauna includes a single species of the New World genus Rhadalus Leconte, 1852.  By far the greatest diversity is in the Palaearctic region and the European fauna includes almost 80 species although only 12 are recorded from central Europe of which 2 species of the largest genus, and that which includes most species of the subfamily, the largely Palaearctic Aplocnemus Stephens, 1830, extend to the UK and are the only representatives of the group to occur here. Species are rather nondescript, resembling large Scirtids, elongate and discontinuous in outline with rounded pronotum and parallel-sided elytra, most are drab brown and distinctly pubescent. They are well-sclerotized, hard bodied and lack the inflatable vesicles seen in malachids, the terminal maxillary palpomere is usually securiform and the basal tarsomere is at least as long as the next. Species are generally associated with trees and shrubs including conifers.

  • DASYTINAE Laporte, 1840 this group includes more than half of all the species of the family and is most diverse in northern temperate regions and only poorly represented in tropical areas. The majority of the UK fauna, 3 genera and 7 species, belong here and are a good representation of the group as a whole. Dasytes Paykull, 1799 is a primarily Palaearctic group of about 300 species; almost 90 species occur in southern Europe of which 16 are listed from central Europe and 5 from the UK. Species are soft-bodied and drab, black or mostly so, with various metallic overtones, the body is clothed with short pubescence and often also long, erect setae, the dorsal surface is randomly and usually finely punctured, the antennae short and variously, sometimes only weakly, serrate and the legs long and slender with 5-segmented and weakly lobed tarsi. Many species are dimorphic with the males having larger and more convex eyes and longer and more slender antennae. Adults occur on flowers from early spring into the summer, and the predatory larvae develop in decaying wood. Dolichosoma Stephens, 1830 is a small and mostly western Palaearctic genus of 13 species, 2 occur in the Nearctic region and 4 are recorded from Europe of which the widespread D. lineare (Rossi, 1794) extends to the UK. Species are distinctive owing to their sub-cylindrical and very elongate form, long tarsi; at least as long as the tibiae, and equal claws. Psilothrix Küster, 1850 is a small Western Palaearctic genus of about 15 species, 11 occur in Europe of which P. viridicoeruleus (Geoffroy in Fourcroy, 1785) extends to the UK where it is a very local and mostly southern-coastal species. The species is large, 4-4.5mm, soft-bodied and distinctively bright metallic green with long legs and short, weakly serrate antennae, the dorsal surface is finely punctured and pubescent. Adults occur on flowers of various herbaceous plants while the larvae are initially ground-dwelling and predatory but later become phytophagous; they pupate in stems and adults eclose in the spring.

  • DANACEINAE Thomson, C.G., 1859 this very speciose group includes only 2 genera and is restricted to the Palaearctic region, they are most diverse in warmer areas, only poorly represented further north and absent from the UK. Danacea Laporte, 1836 includes almost 300 species of which about 120 occur in warmer parts of southern Europe but only 9 extend into central Europe and only 2 extend further north. Species are elongate and discontinuous, rather typical of the family, drab-coloured but covered in dense scale-like pubescence which gives many species a grey or greenish metallic appearance, in most the appendages are pale and contrast with the body.  Distinctive characters include a quadrate labrum which is usually produced forward, smooth and simple mandibles i.e. without bi- or multidentate tips, and the posterior claw of at least the metatarsi, and often all tarsi, shortened and peg-like. Like most members of the family they are diurnal and occur on various flowers. Hylodanacaea Pic, 1926 is a Neotropical group of about 20 species but many more remain to be described.

  • LISTRINAE Majer, 1990 A large group of 25 genera and about 180 species, the greatest diversity is in the Nearctic region with 21 genera and about 170 species. The Palaearctic fauna includes 4 species of 3 genera from Asia but none occur in Europe. Beyond this a single genus occurs in Africa. The majority of species, more than 120, are included in the Nearctic genus Trichochrous Motschulsky, 1859. They are distinguished among the family by the pronotum and elytra being fringed with fine setae and the form of the tarsi; the two basal segments are equal in length and the claws lack a basal tooth but are variously furnished with a long ungula appendage which may be attached throughout their length. They are otherwise typical of the family; drab black to various shades of brown or, rarely as in some species of Trichochrous Motschulsky, 1859, bicoloured with the foreparts contrasting with the elytra, elongate-oval and discontinuous in outline and generally resembling Dasytes.

Ecology

In the UK members of this family may be found by sweeping grassland with abundant flowers, especially where this is close to wooded areas, in the spring and early summer, beating low foliage of trees and shrubs may also be productive and our 2 species of Aplocnemus may also be found under bark; A. impressus (Marsham, 1802) under conifer bark, especially when the trees are flowering, and A. nigricornis (Fabricius, 1792) under bark of old deciduous trees where the larvae predate scolytid larvae. Larvae are predatory or largely so and live among decaying wood or under bark while the adults are predatory as well as pollen feeders.

Description

Diagnostic features of the family include the overall shape; elongate, rather parallel-sided and discontinuous in outline with a large head, which may be variously hidden within the pro-thorax, large convex eyes and medium-length, slender or distally thickened but usually to some degree serrate, antennae. In UK species the first and third antennomeres are about equal in length. In most the apical maxillary palpomere is conical. The upper surface is usually randomly and finely punctured and variably pubescent. They lack the eversible vesicles on the pronotum and elytra seen in malachids and have transverse meta-coxae which lie perpendicular to the body axis; in malachids they are oblique. The pronotum is quadrate to elongate, weakly and evenly convex or with wide and shallow basal fovea; bordered or un-bordered lateral margins and is generally narrower than the elytral shoulders. Prosternum short anterior to transverse and contiguous coxal cavities. All coxae transverse; pro- and meso-coxae conical and clearly protruding. All abdominal segments free. Elytra elongate with well-developed shoulders, parallel to weakly rounded laterally and continuously (Dasytes) or discontinuously rounded (Dolichosoma). Legs long and slender, all coxae clearly 5-segmented and not, or only very weakly lobed, a feature that will distinguish them from cantharids which have various segments widely bilobed. With the exception of Psilothrix our species are drab-coloured black to dark brown with or without a metallic lustre. Within the limited UK fauna our species soon become familiar.

A key to the UK species can be found HERE.

UK Species

Aplocnemus impressus

Dasytes virens

Aplocnemus nigricornis

Psilothrix viridicoeruleus

Dolichosoma lineare

Dasytes cyaneus

Dasytes niger

Dasytes plumbeus

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