Scolytus costellatus Chapuis, 1869

V. Petrov, Alexander & Y. Mandelshtam, Michail, 2010, New data on Neotropical Scolytus Geoffroy, 1762 with description of five new species from Peru (Coleoptera, Curculionidae, Scolytinae), ZooKeys 56, pp. 65-104 : 77-78

Scolytus costellatus Chapuis, 1869 Fig. 13

Material examined: Peru: Loreto province, 58 km SW from Iquitos to Nauta, Rio Perene, 120 m a.s.l., 11.02.2005 A.Petrov (3♀♀), same locality, but 9-12.02 2007 (3♂♂, 2♀♀), same location but 5-8.02.2008 A.Petrov (1♂♂, 4♀♀). Junin province, Perene river, 11 km from Puerto Ocopa vill, Los Olivos, 1180 m a.s.l., 11°3.00'S; 74°15.52'W 26-31.03.2009 A.Petrov (1♂, 2♀♀). Cusco province, 4 km SW from Machu Picchu, 1300 m, 21.IV.2009, A.Petrov, (1♀)

Diagnosis.

Species differ from all other representatives of genus by the narrowed, pointed antennal club and by the reduced scutellum. Also diagnostic for the species are equally deepened elytral striae and interstriae, male second sternite with nearly sharp transverse carina, occupying most portion of second sternite base.

Description.

Male: body length 3.2-4.1 mm, 1.8-1.86 times as long as wide; body black, shining. Head black, faintly shining, with dark brown mandibles. Front flat, evenly longitudinally aciculate from vertex and to lower portion of epistoma. Central portion of front is covered by sparse golden hairs, at lateral sides and on upper margin of front these hairs thicker and longer, with their apices directed towards the centre of front, forming a golden brush. Antennae with reddish-brown scapus and two first funicular segments; club and segments 3-7 of funiculus dark grayish-brown. Club with a narrowed and pointed apex covered with short gray hairs (Fig. 13). Pronotum 0.9-1.0 times as long as wide, central part of basis with the projection overhanging above scutellum, its surface smooth and shining, with small punctures at base and in central part, at anterolateral angles, punctures are larger and of moderate size. Apical margin of pronotum with sparse thin and short hairs. Pronotum is divided from prosternite by the well-developed acute lateral margin. Lateral sides of pronotum (propleura) are abundantly and evenly punctured with punctures of size equal to size of punctures at lateral margins of pronotum.

Scutellum is reduced, nearly obsolete.

Elytra 0.9-1.0 times as long as wide, 0.9-1.1 times as long as pronotum, striae and interstriae are equally sulcate from base to declivity of elytra; punctures in striae and interstriae are small, about equal in size, spaced by diameter of a puncture; entire elytral surface covered by short, erect, dark setae. Declivity weak, with strongly confused puncturation. Abdomen black, its surface nearly dull, sternites abundantly and densely punctured by punctures of different size, punctures on second sternite are four-time larger than punctures on sternites 3-5. Transversal length of second sternite is two-times greater its longitude, second sternite set subvertical to first sternite, its anterior margin subacutely costate on median area; fifth sternite with weakly elevated posterior margin; sternites covered by erect pale moderately long hairs. Legs black, tarsi reddish-brown, meso- and metafemora with long pale hairs.

Female: similar to male except front weakly convex, frontal width and form are very variable, in some females in upper portion of front there is a thin median line, vestiture in lateral margins shorter but abundant; second sternite with costa absent, its base rounded, anterior margin with small bifurcated callus, erect abdominal setae shorter than in male.

Notes: After examination of the type specimens of Scolytus pseudocostellatus and Scolytus strigipennis we concluded that both species are junior synonyms of Scolytus costellatus . The features considered as species-specific fall into intraspecific variability of Scolytus costellatus.

Host.

Liana.

Biology.

Infest the lianas that were mechanically damaged. The egg galleries very long, longitudinal, biramous. Egg chambers are located strictly on one side of the egg gallery. Number of egg chambers varies from 55 to 95. The larval galleries are perpendicular to the main egg gallery, do not cross one another, form a circle around the liana stem and run back towards the egg gallery from another side where deepen into xylem, where the pupal chambers are formed.