Paradromius linearis (Olivier, 1795)
This western Palaearctic species occurs from lowland to low mountain regions throughout Europe to the south of Fennoscandia, extending south to North Africa, including all the Mediterranean islands, Egypt, Caucasus and Russia east to the Ural Mountains; it is common and often abundant across most of its range although in some northern European regions it tends to be more coastal but some northern areas have seen an expansion in recent decades. Here it is abundant throughout lowland England and Wales, rather sparse and mostly eastern-coastal to the north of Scotland, and very local through Ireland. Adults are likely to be encountered in most situations, especially during the warmer months when they are very active on vegetation, but in general they prefer dry situations with plenty of vegetation e.g. grassland, parkland. Dunes, wasteland and road verges etc. and they will often occur in domestic gardens and other disturbed situations. Adults are present year-round and active over a very long season; depending on the season they may be found from February until November although they are also active in mild spells through the winter, during January or February they may be found on fence posts or around the base of trunks, and soon they are active on vegetation, climbing stems and roaming foliage. They are mostly nocturnal but in hot weather they may be swept from vegetation by day or night and may be particularly abundant along arable and woodland margins or occasionally in reed beds. Mating occurs mostly in the spring, during March and April, but also occurs commonly in the autumn, eggs are laid in small batches in the soil around the base of plant stems and larvae develop either in the soil or within hollow stems. Larvae have been recorded in every month; in the winter in plant stems or other sheltered situations, and otherwise in the soil generally, older larvae occur in the summer and these may produce adults that mate in the autumn and either lay eggs that produce overwintering larvae, or overwinter to oviposit in the spring. The majority of new-generation adults appear towards the end of summer, overwinter and mate in the spring but the species may be continuously breeding, at least over parts of its range. Both larvae and adults are predatory on small insects and springtails etc. Sampling adults is simple as they will appear regularly in the sweep net during the warmer months, at night they are likely to be seen on stems etc. at any time of the year; they usually mate on posts or trunks and pairs are easily observed in late winter and spring.
Paradromius linearis 1
Paradromius linearis 2
Paradromius linearis 3
These small beetles, 4.5-5.5mm, are characterized by the pale colour, glabrous and truncate elytra and elongate form. Entirely pale brown, including all appendages, usually with the head, pronotum, elytral apices and suture darker. Head elongate and proportionally large; virtually as wide as and longer than the pronotum, vertex smooth but for longitudinal striations beside each eye, eyes convex and quite prominent anterior to long and tapering temples. Antennae long and slender, second segment shorter than the first and third, all segments elongate, becoming less so and a little broader towards the apex. Pronotum quadrate, broadest behind rounded anterior angles and strongly sinuate and narrowed to sharp and protruding posterior angles, basal margin weakly curved. Elytra very elongate, about 2.5 times longer than wide, with sloping shoulders and a truncate and slightly sinuate apical margin, striae complete to apical fifth or so, weakly-impressed and distinctly punctured, in places consisting only of rows of punctures and not impressed, scutellary stria missing, interstices flat and unpunctured. Legs long and slender, pro-tibiae with an internal antenna-cleaning notch. Tarsi 5-segmented, all segments elongate. Claws serrate. The majority of specimens lack wings.