Leistus rufomarginatus

Rotrandiger beard runner

The Rotrandige Beard Runner ( Leistus rufomarginatus ) is a beetle of the family of beetles and the subfamily Nebriinae. Synonyms are Leistus otomanus Schweiger 1970 and Leistus italicus A. Fiori 1913. Leistus The genus is represented in Europe with over forty species. The Rotrandige beard runner belongs with sixteen other European species in the subgenus Pogonophorus.

The generic name from Ancient Greek Leistus ληίστης, Leiste ' robbers ' expresses that the species is predatory. The name of the subgenus Pogonophorus of ancient Greek πώγων, POGOŃ ' beard ' and φορώς, Phoros ' supporting ' means beard '. The term is due to the visible side of the bristles of the mouthparts. The species name rufomarginatus from the Latin rufus ' red 'and' marginatus ' margins ' refers to the red edge of the pronotum.

Characteristics of the beetle

The beetle reaches a length of 7.5 to 9.5 millimeters. With out colored copies head, chest plate and wing coverts are dark brown, legs, feelers and mouth parts are lighter and reddish brown.

When viewing the head immediately fall on the very broad, lamellar, and only relatively weakly sclerotized maxilla laterally extending above the head. They are pulled down the side, grooved on the outside of the basal area and contribute in this furrow a pore with bristle point. They are sharply pointed, the right maxilla bears inside a tooth that is missing the left. The lower jaws are widened and wear on the outer edge three conspicuous teeth and other tooth-like extensions, and arranged in a row long bristles. The four-membered Kiefer button and the tripartite labial palpi are slender and long, truncated their end members. The lower lip is tridentate and thorns at the base all around. The upper lip is stiff front ciliated. Overall, the bristles of the mouthparts form in all species of the genus Leistus a downwardly opening pot which the escape of surprised prey (mainly springtails ) prevented ( Fig. 1). The eleven-membered antennae are filiform, the last eight limbs finely hairy. The third sensor element is only about twice as long as the second. The roundish eyes are curved hemispherical.

The heart-shaped pronotum is almost twice as wide as long. Its edge is offset by a wide groove ( pronotum throat ), which is significantly wider on the side as the second antennal segment long. The pronotum throat is in contrast to the middle of pronotum distinctly punctate and reddish brown. Towards the base, the pronotum narrowed to approximately the width of the head.

The elytra have a lighter, but less striking edge. They are long and slender. At the base they wear outside a Basalzähnchen. Behind the basis they widen quickly and are wider than the pronotum behind the half, but shoulders are at most indicated. At the end of the wing-coverts are pointed together. They carry nine distinctive dot stripe and another much shorter strip next to the tag ( Scutellarstreif ).

The front Hüfthöhlen are open at the back. The legs are long and slender and betray the fast runners. The tarsi are five-membered all clear.

Larva

The larvae are characterized by the long-drawn first breast segment, the pedicled head and two long cerci. However, this applies for all the larvae of the genus. In Leistus rufomarginatus the Cerci wearing only a very short bristles ( Fig. 5).

Biology

The kind with respect to the choice of habitat is not picky, it is sufficient that the humidity is high. The beetle is preferably used in the leaf litter of moist deciduous forests before, rarely also in meadows and other open habitats. At higher altitudes, it is also found in coniferous forest. The animals are usually portrayed as good flyers with fully developed wings ( makropter ), in other places with vestigial wings ( brachypterous ) and flightless. The occurrence makropterer and brachypterer populations within the same species, however, is to be found more often in ground beetles.

The adults are active in Central Europe in the fall. The species overwinters as a larva almost exclusively and rarely as Imago.

Dissemination

The species is widespread in Europe and grasped their range in expansion. The beetle is absent in the southwest (Spain, Portugal) and in the far north. Even within Central Europe decreases the frequency from east to west and north. The type of postglacial spread from refugia in the Balkans. In the UK it was reported in the mid- 20th century for the first time and quickly spread. Today it is represented in the southeast of the island most common, but in the whole of England. Meanwhile, the species is also reported from Scotland. The northern distribution limit in Europe passes through Norway, Sweden and Lithuania.