Hylurgops palliatus (Gyllenhal, 1813)

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POLYPHAGA Emery, 1886

CURCULIONOIDEA Latreille, 1802

CURCULIONIDAE Latreille, 1802

SCOLYTINAE Latreille, 1804

HYLASTINI LeConte, 1876

Hylurgops LeConte, 1876

This species is generally common and often abundant in coniferous and mixed woodland throughout the Palaearctic region, from Portugal to the far east of Russia, China, Sakhalin and Japan. To the south it reaches South Korea, Asia Minor and North Africa and, following introductions, it is now widespread though sporadic in North America, beyond this it is regularly recorded from imported timber in many countries around the world. In Europe it occurs from lowlands to the tree line in mountain regions and the distribution extends from the Mediterranean to the UK and the far north of Fennoscandia. The species is generally common in suitable sites across England and Wales, it is widespread and locally common in the northern Highlands though otherwise largely absent from Scotland, and it has been recorded from Ireland. Adults are present year-round; they are active from March until October and peak in abundance during May and June. In the UK the usual host is Norway Spruce (Picea abies (L.)), but more generally the beetles develop in a wide range of coniferous trees, including other species of spruce, pines (Pinus L.), larches (Larix Mill.), fir (Abies Mill.) and Common Juniper (Juniperus communis L.) Overwintered adults become active and disperse by flight in the spring when the temperature reaches 6°C, they peak in activity early in the season, during April or May, but dispersal flights continue until June. In general Hylurgops is a secondary species, attacking dead or dying trees, stumps and logs already infested with scolytids, it prefers logs or fallen timber from the previous year and often attacks lower parts of trees (up to 2 m) or roots or timber in contact with the ground. Immature beetles bore into bark during the spring and produce irregular feeding galleries, they mature within a few weeks and leave these galleries to find suitable material in which to breed. After mating females excavate galleries between 2 and 5 cm long in which they lay up to 65 eggs. Larvae mine randomly, they do not produce any distinctive gallery formations and heavy infestations may consume the entire phloem in individual trees. Pupation occurs at the end of the feeding galleries from July and new-generation adults appear from August. These adults generally overwinter under bark near the gallery systems but will occasionally leave and overwinter in roots or among litter beneath logs etc. Adult generations overlap during the summer and all life stages may be present during July and August. In Northern Europe the species is univoltine but further south there may be second generation and winter may be passed in the larval stage. Adults may be found by general searching in suitable habitats through the year, in spring and early summer they fly in the evening and at night and may be sampled using flight-interception traps, they are attracted to alcohol traps (ethanol, but hardly at all with other alcohols) and large numbers have been attracted to alcohol/a-pinine mixtures and various monoterpenes. For a further introduction to the species see HERE.

Hylurgops palliatus 1

Hylurgops palliatus 1

Hylurgops palliatus 2

Hylurgops palliatus 2

2.3-3.4 mm. Elongate, broadly cylindrical with a tapering forebody and robust legs, head black, body and legs brown, antennae brown with the club darker. Head visible from above, produced and flattened in front of broadly reniform eyes and densely punctured throughout, anterior clypeal margin with dense pale pubescence. Antennae inserted laterally in front of the eyes, scape long and broadened from the middle, funiculus 7-segmented and club 4-segmented, elongate, compact and conical, not flattened. Pronotum transverse, broadest in the basal half and constricted before a rounded apical margin, posterior angles rounded and obtuse, basal margin produced medially, surface densely punctured with punctures varying in size, and with a narrow median longitudinal unpunctured line. Elytra parallel-sided from rounded and finely crenulate basal margins to a continuously rounded and smoothly convex apex, basal margin not raised, interstices raised, slightly wider than strongly punctured striae and with short pale setae. Femora long and unmodified, tibiae with external spines, front tibiae produced and strongly toothed subapically. Tarsi 5-segmented, the third bilobed and clearly wider than the second, the forth diminutive and the terminal segment long and curved.