Exocentrus stierlini Ganglbauer, 1883

Karpinski, Lech, Szczepanski, Wojciech T., lewa, Radoslaw, Walczak, Marcin, Hilszczanski, Jacek, Kruszelnicki, Lech, Los, Krzysztof, Jaworski, Tomasz, Marek Bidas, & Tarwacki, Grzegorz, 2018, New data on the distribution, biology and ecology of the longhorn beetles from the area of South and East Kazakhstan (Coleoptera, Cerambycidae), ZooKeys 805, pp. 59-126 : 96

Exocentrus stierlini Ganglbauer, 1883 Fig. 4G, H

Material examined.

East Kazakhstan Region: Putintsevo [ Путинцево] env. (49°52'N, 84°21'E), 472 m a.s.l., 19-23 VI 2017, 3♂♂, 2♀♀, leg. WTS; 1♂, leg. LK; 1♂, 1♀, (VI 2018 ex cult.) 2♂♂, from Salix sp., leg. MW; 2 exx., red wine trap, coll. LK & MB.

Remarks.

Exocentrus stierlini is an extremely rare but widespread species that is distributed from Central Europe to the Far East including northern Mongolia ( Danilevsky 2014b, 2018a). Its occurrence in Mongolia was proven only very recently ( Müller et al. 2013), similar to that of the Ulyanovsk region of Russia ( Isaev and Ishutov 2001). According to Danilevsky (2014b), it is known to be monophagous on Salix within its entire range and there are no differences between specimens from Europe, Siberia and the Far East. The larvae develop in thin (6-22 mm diameter) willow shoots of both trees that are still alive or that are decaying. Pupation begins in May and continues until July. The adults occur in nature from June to August. Newly emerged imagines require supplementary feeding, which is conducted on the bark of young willow shoots. They lead a cryptic mode of life and can be found almost exclusively on their host plants ( Cherepanov 1991a).

Although this species has already been mentioned as occurring in Kazakhstan ( Danilevsky 2018a), this record was based only on the assumption concerning a single specimen from Staroaleyskoye (Altai Region of Russia, approx. 25 km from the Kazakh border) that is preserved in the collection of P. Svacha ( Danilevsky 2014b, 2018, pers. comm.). However, until now, no specimens have been known directly from the borders of this country. Therefore, the presented locality in the area of Putintsevo is the first record for Kazakhstan.

Several specimens were beaten down from both live and dead willows of different ages, during hot and sultry weather in a deciduous forest that extends along the Khamir River in the foothills of the West Altai Mountains (Fig. 15D). The imagines of E. stierlini were collected in a few different habitats within one area in the Putinsevo environs. In addition to the rather shady and humid forest dominated by Populus and Salix where most of the specimens were found, beetles were also observed on an exposed site next to a river that had an admixture of Betula as well as in a more open habitat of a rather old Populus forest (Fig. 15F). At the last plot, two specimens were found in red wine traps. This is a rather peculiar observation concerning the representatives of the subfamily Lamiinae ; however, the traps were hung in an air corridor, hence, they might have served as a mechanical barrier. Nevertheless, both individuals were caught on different days. Two mating couples were also observed. Only ten specimens were collected despite conducting many hours of targeted investigation over a few days during a rather optimal period, which underlines the rarity of this species. Attempting to attract them to an artificial light source, even at the site where the imagines were collected, did not provide the expected results. Exocentrus stierlini occurred sympatrically with other Lamiinae species, such as Saperda similis , Lamia textor and Rhopaloscelis unifasciatus .