Augyles Schiødte, 1866

Suborder:

Superfamily:

Family:

Species:

POLYPHAGA Emery, 1886

BYRRHOIDEA Latreille, 1804

HETEROCERIDAE MacLeay, 1825

A. hispidulus (Kiesenwetter, 1843)

A. maritimus (Guérin-Méneville, 1844)

This is a small Holarctic genus of about 35 species; the greatest diversity is in the Palaearctic region while 5 species are known from North America. Twelve species of two subgenera occur in Europe and all but one, A. (Phyrites Schiodte, 1866) aureolus (Schiodte, 1866), are included in the subgenus Littorimus Des Gozis, 1885. Two species occur in the UK, both of which are widely distributed though generally very local and scarce in Europe. The genus was formerly included as a subgenus of Heterocerus Fabricius, 1792 and adults of the two groups are very similar; in Heterocerus the stridulatory ridge on the first visible abdominal sternite extends obliquely from the lateral margin at the base to the apical margin where it finishes while in Augyles this ridge extends obliquely from the lateral margin at the base to the apical margin and then recurves back towards the centre by the hind coxae. There are no reliable morphological characters to distinguish the sexes but males are usually smaller, more slender and have more robust mandibles and clypeus, these features are not always obvious but can usually seen between series. In all other respects the genera are closely similar and easily confused. Our species are readily identified as follows:

-Pronotum broadest near the base and narrowed to finely-rounded anterior angles. Antennal club 6-segmented. Longest hairs on the elytra forming distinct rows, at least in places. Anterior tibiae with 6-7 external spines. 2.7-3.6 mm.

----A. hispidulus

-Pronotum weakly curved and almost parallel-sided to rounded angles. Antennal club 7-segmented. Longest hairs on the elytra randomly arranged. Anterior tibiae with 8-9 external spines. 2.5-3.3 mm.

----A. maritimus

Augyles hispidulus

Augyles hispidulus

© Lech Borowiec

Augyles maritimus

Augyles maritimus

© U.Schmidt

The biology is typical of the family with colonies of adults living and breeding in marginal wetland habitats, overwintering and dispersing by flight in spring and summer. They spend much of their time burrowing among the substrate but they often walk in the open on warm spring and summer days. Within a colony a single male and female may occupy a burrow and, after reproducing in the spring, these burrows may also be occupied by larvae which will develop and pupate among the wet substrate. Both stages feed on microorganisms, ingesting the substrate to do so.

Augyles hispidulus (Kiesenwetter, 1843)

This western Palaearctic species is widespread across central and southern Europe; it tends to be very local and scarce in the north where it extends to the UK and some southern provinces of Fennoscandia, but it becomes more common towards the south where it occurs sporadically from Spain to Greece. Beyond this it occurs in western Russia and has been recorded from Turkey, Iraq, Uzbekistan and Turkmenistan. The species was first recorded in the UK in 1969 from East Sussex, since that time it has been slowly spreading and there are modern coastal records from Sussex and Kent and inland records from East Anglia. On the continent the species inhabits freshwater coastal sites and margins of inland rivers while in the UK it is mainly associated with disturbed sites such as sand and gravel pits with extensive areas of damp substrate devoid of vegetation. Adults are active from March until October, peaking in abundance in late spring and again in late summer. They spend much of their time among organic rich detritus just below the surface but on warm days they become active and may appear on the surface in large numbers, they sometimes fly in numbers in warm weather and might occur far from suitable habitat. Little is known of the life history but it is likely that adults overwinter and that larvae develop among sandy substrate during the summer.

2.7-3.6 mm. Forebody black, elytra variable but usually yellow with the base, suture and two irregular and sometimes interrupted black markings, legs black to dark brown or with darker femora or paler tarsi, antennae brown, usually with darker clubs. Entirely pale or entirely dark specimens are not uncommon. Head almost flat between large convex eyes, and with dense pale pubescence, especially anteriorly. Pronotum broadest across perpendicular or very slightly obtuse posterior angles and narrowed to a curved apical margin, the anterior angles not obvious from above, surface finely punctured and pubescent throughout and often with obscure impressions towards the base, basal margin finely bordered. Elytra parallel-sided or (usually) slightly dilated from rounded shoulders to a complete apical margin, surface finely and randomly punctured and usually with partial or almost entire longitudinal striae or impressions, with dense short pubescence and sparser longer hairs that form regular rows. Front and middle tibiae with long stout spines externally, hind tibiae with a few spines only towards the apex. All tarsi with four unmodified segments, claws simple.

Augyles maritimus (Guérin-Méneville, 1844)

This is a mostly western European and Mediterranean species; it occurs from Portugal to Turkey and from Morocco to Tunisia and is present on the larger islands. To the north it extends to the UK and along the coast as far as Poland. The species is associated with saline or brackish environments and so is generally restricted to coastal areas but it also occurs inland near salt workings etc., it is much more common in the south and very local and rare in the north but it occurs abundantly at a few northern coastal sites and at a few inland sites on the Iberian Peninsula. In the UK this is a mostly coastal species although there are a few inland records from the English midlands, it is very local and generally scarce around the coasts of England and Wales and there are a few records from Scotland and Northern Ireland. Typical habitats are brackish tidal rivers, estuaries, ponds and saltmarshes where, despite being very local, adults usually occur in abundance. The species can tolerate a wide range of salinity; it sometimes occurs at coastal freshwater sites but it cannot survive hyper saline conditions. Adults usually occur on permanently wet silty or sandy substrates, usually close to water and usually with sparse and patchy vegetation; they have been recorded year-round and are active over a long season from early spring, peaking in abundance during May or June. Sampling adults is usually easiest by searching among suitable substrates where their burrows produce small raised tracks on the surface, they can be sieved but flooding small areas will quickly produce them, on warm days they are active and may often be found in numbers under matted algae.

2.5-3.3 mm. Body narrow and rather parallel-sided, head black or dark brown, pronotum dark with paler margins and sometimes a pale longitudinal line down the centre, elytra a little paler and usually with obscure reddish markings that vary in size, legs reddish brown, antennae pale with darker clubs. Entirely dark or entirely pale specimens are not uncommon. Dorsal surface with pale pubescence which is especially dense on the head and anterior pronotal margin, on the elytra forming distinct layers, the longer outstanding hairs not arranged in longitudinal rows. Pronotum transverse and usually a distinctly wider than the elytra, parallel-sided and with widely-rounded angles, surface finely and densely punctured throughout. Elytra smoothly convex, almost parallel-sided fro rounded shoulders to a continuous apical margin, densely punctured with very fine punctures between dense larger punctures, without striae but often with short longitudinal depressions at the base. Front and middle tibiae with long stout spines externally, hind tibiae with a few spines only towards the apex. Tarsi with four unmodified segments, claws simple.