Hylastes substriatus, Strohmeyer, 1914

Mandelshtam, M. Yu. & Petrov, A. V., 2019, A key to species of the tribe Hylastini LeConte, 1876 (Coleoptera: Curculionidae: Scolytinae) from Russia and adjacent countries, Russian Entomological Journal 28 (4), pp. 389-399 : 394

10. H. substriatus Strohmeyer, 1914

Figs 2, 5 , 12, 15, 17 , 21–22 , 28 .

DISTRIBUTION. Middle Asia (Kirgizia, Kazakhstan: Trans-Ili Alatau), Asia (Western China). Records from Turkey [ Knížek, 2011] are doubtful; probably absent in Turkmenistan and Uzbekistan [ Stark, 1952].

HOSTS. Picea schrenkiana , also recorded from Pinus sylvestris [ Temreshev, Kolov, 2013; Temreshev et al., 2016].

BIOLOGY. This species infests only unhealthy, damaged trees. The species preferentially attacks standing trees usually already weakened by other bark and phloem tunneling insects. On fallen trees, the galleries are built on the lower part of the trunk which is in contact with the ground. One necessary condition for successful breeding is high humidity; hence, the species is most common nearby mountain rivers and streams [ Temreshev et al., 2016]. It can be found very rarely on naked roots or roots surrounded by the dry litter [ Stark, 1952]. Galleries are built usually in the root neck of spruces in area covered by litter or mosses. According to Marikovskiy [1956], H. substriatus lives in large roots of spruces, under a layer of soil up to 30–40 cm deep. The species is monogamous as other Hylastes species. There is one generation per year. Larvae overwinters [ Parfent’ev, 1951], however it was reported [ Temreshev et al., 2016] that beetles and pupae may also overwinter. Beetles are active during all summer period starting from May, mass flight period is restricted by mid-May and beginning of June. The species frequently uses galleries of Ips hauseri Reitter, 1895 for penetration under the bark and for maturation feeding [ Temreshev et al., 2016]. Beetles build a longitudinal parental gallery under the bark, where larval galleries are tightly spaced, crossing and fusing into one cavity filled by frass. Imagines emerge at the beginning of August. Maturation feeding then occurs in the galleries and also in the bark of root necks and roots of young spruces and pines [ Temreshev et al., 2016]. H. substriatus is a very common species in Picea schrenkiana windbreak sites in Ile-Alatau National Natural Park [ Temreshev, Kolov, 2013]. Besides, the species was found on pine and spruce logs in lumber yards in Almaty Province of Kazakhstan.

Figures

Figs 1–6. Bark beetles of the genus Hylastes: 1 — Hylastes cunicularius; 2, 5 — H. substriatus; 3 — H. brunneus; 4, 6 — H. ater; 1–4 — habitus, dorsal view; 5–6 — elytral declivity; 1–4 — males; 1, 3 — Photographs from www.zin.ru\Animalia\Coleoptera. Author Kirill V. Makarov. Used with permission as indicated on website. Рис. 1–6. Короеды рода Hylastes: 1 — Hylastes cunicularius; 2, 5 — H. substriatus; 3 — H. brunneus; 4, 6 — H. ater; 1–4 — габитус, вид сверху; 5–6 — скат надкрылий; 1–4 — самцы; 1, 3 — фотографии с www.zin.ru\Animalia\Coleoptera. Автор К.В. Макаров. ИспольЗуютсЯ с раЗрешениЯ автора.

Figs 12–20. Habitus and details of bark beetles of the genus Hylastes and Hylurgops:12, 15, 17 — Hylastes substriatus; 13 — Hylastes ater; 14 — Hylurgops palliatus; 16 — Hylastes attenuatus; 18 — Hylastes cunucularius;19–20 — Hylurgops glabratus; 12 — protibia and tarsus; 13–14 — tarsi; 15–16 — head; 17–19 — pronotum; 20 — habitus, dorsal view. Рис. 12–20. Габитус и детали строениЯ короедов родов Hylastes и Hylurgops: 12, 15, 17 — Hylastes substriatus; 13 — Hylastes ater; 14 — Hylurgops palliatus; 16 — Hylastes attenuatus; 18 — Hylastes cunucularius; 19–20 — Hylurgops glabratus; 12 — переднЯЯ голень и лапка; 13–14 — лапки; 15–16 — голова; 17–19 — переднеспинка; 20 — габитус, сверху.

Figs 21–26. Male genitalia of bark beetles from genera Hylastes and Hylurgops: 21–22 — Hylastes substriatus; 23 — Hylastes linearis; 24 — Hylastes ater; 25 — Hylastes brunneus; 26 — Hylurgops palliatus; 21, 23–26 — dorsal view; 22 — lateral view. Рис. 21–26. Гениталии самцов короедов родов Hylastes и Hylurgops: 21–22 — Hylastes substriatus; 23 — Hylastes linearis; 24 — Hylastes ater; 25 — Hylastes brunneus; 26 — Hylurgops palliatus; 21, 23–26 — сверху; 22 — сбоку.

Figs 27–30. Male ventrites 5 of bark beetles of the genus Hylastes: 27 — H. ater; 28 — H. substriatus; 29 — H. brunneus; 30 — H. cunicularius. Рис. 27–30. ПЯтые членики брюшка самцов короедов рода Hylastes: 27 — H. ater; 28 — H. substriatus; 29 — H. brunneus; 30 — H. cunicularius.