Scolytus scolytus

Scolytus scolytus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Family:	Curculionidae
Subfamily:	Scolytinae
Genus:	Scolytus
Species:	S. scolytus
Binomial name
Scolytus scolytus (Fabricius, 1775) [1]
Synonyms
Bostrichus scolytus Fabricius, 1775 Dermestes geoffroi Goeze, 1777 Dermestes scolythus Sulzer, 1776 Dermestes scolytus geoffroi Goeze, 1777 Eccoptogaster scolytus (Fabricius, 1775) Ekkoptogaster scolytus (Fabricius, 1775) Hylesinus scolytus (Fabricius, 1775) Ips scolytus (Fabricius, 1775) Scolytus californicus LeConte, 1868 Scolytus destructor Olivier, 1795 Scolytus destructor var. ciliaris Rey, 1892 Scolytus fuchsi Reitter, 1913 Scolytus niger Geoffroy, 1785 Scolytus punctatus Müller, 1776 Scolytus scolytus var. variabilis Sokanovsky, 1958 Scolytus triarmatus Eggers, 1912 [2][3]

Scolytus scolytus, the larger European elm bark beetle or large elm bark beetle, is a 3.5–6 mm long bark beetle species.^[4][5] It is of significant importance in Eurasia as a vector of Dutch elm disease.

Description

Pronotum black and shiny, with red-brown anterior and posterior margins. Elytra, antennae, legs and abdomen are red-brown. Forehead with fine wrinkles and tubercles and a thick brush of hairs. Female's forehead convex, male's is flattened. Elytra bear well developed but shallow longitudinal punctate grooves. Elytra are tapering posteriorly. Abdomen sharply concave, oblique to the tip. In the middle of the posterior edge of the third and fourth abdominal segments there is usually an acute tubercle. The males have a continuous (although incrementally shorter toward middle) brush of golden hair at the apex of the abdomen.^[4][5]

Life cycle

The first generation flies mainly in June, in certain years stretching from the end of May to the middle of July. The second generation flies in August. Females prefers to lay their eggs under the bark of the lower part of the trunk, in areas where the cortex is thicker, most often on weakened standing trees or fallen trees. Egg galleries are longitudinal, 2–7 cm long, over 2 mm wide but no more than 3 mm. Larval galleries start perpendicularly from the egg gallery, the upper ones are bent upward, the lower ones downward, and the ones at the middle run rather parallelly from ones another. Larval galleries located on lower parts of the trunk are imprinted on the inner surface of the cortex, sometimes on the sapwood too to some extent. Pupal chambers are usually located in the bark. After emerging, adult beetles feed on the crotch of young twigs, of leave petioles, and others. Partly-developed to fully developed larvae overwinter. In the northern part of its range there is usually one generation per year, in the steppes 1 to 2 generations, and in the Caucasus usually 2 with possible indications of a third one.^[4][5]

Distribution

This species has been reported from throughout Europe and western Asia. In Russia, approximately as far east as Irkutsk Oblast and as far north as the southern boundary of the taiga zone. In Asia, it has also been reported from Turkey, Armenia, Azerbaijan, Georgia, Kazakhstan, China, northern Iran, and northern India (Jammu and Kashmir). In Africa, it has been reported from Morocco and Algeria.^[2][3][5][6]

Host plants

Reported host plants are primarily elms (Ulmus americana, Ulmus glabra, Ulmus hollandica, Ulmus laevis, Ulmus minor, Ulmus procera, Ulmus pumila), but also, common ash, common walnut tree, Caucasian zelkova , as well as a number of trees in the genera Prunus (stone fruits), Quercus (oaks), Salix (willows), and Populus (for black poplar and aspen).^[2][3][5]

References