Three species of bark beetles (Coleoptera: Curculionidae, Scolytinae) on Pinus peuce in Pirin Mountains in Bulgaria

In 2020 and 2021, three species of bark beetles (Coleoptera: Curculionidae, Scolytinae) were established on Macedonian pine (Pinus peuce) in the region of Vihren hut in Pirin Mts. Branches, damaged by snow were collected and studied in laboratory conditions. As a result, 24 specimens of Ips amitinus were reared in 2020 and 81 specimens of I. amitinus, Crypturgus pusillus and Pityogenes chalcographus in 2021. The most abundant species was I. amitinus with 75.2%, followed by P. chalcographus (21.9%) and C. pusillus (2.9%).


Introduction
The Balkan endemic Macedonian pine (Pinus peuce Griseb.) is distributed in mountain areas of North Macedonia, Bulgaria, Greece, Kosovo, Albania and Serbia. It grows between 1000 and 2300 m a.s.l., where it is affected by a wide range of abiotic and biotic factors, including many insect pests. In Bulgaria, the studies on harmful entomofauna of P. peuce are still fragmentary, although some species, mainly bark beetles (Coleoptera: Curculionidae, Scolytinae), have been reared and reported in association with this host (Tschorbadjiew, 1927(Tschorbadjiew, , 1929.
This note reports three species of bark beetles found on Macedonian pine in Pirin Mts. in Bulgaria.

Material and Methods
The studies were conducted in the region of Vihren hut in Pirin Mts. Cuttings of broken by snow branches of P. peuce (approximately 25-30 cm in length with diameter 2-8 cm) were collected on 3 August 2020 and 26 July 2021 from 150 year-old natural stands at an altitude of 1980 m a.s.l. and with geographical coordinates 41.761809 N, 23.417165 E.
The cuttings were transported to the Forest Research Institute in Sofia. They were placed in photoeclectors at room temperature (18-22 °C). The samples were examined weekly to detect the insect emergence.
At the end of the studied period, the barks of the cuttings were removed and the samples were analysed in detail. The emerged bark beetles were identified following the keys of Karaman (1971) and Grüne (1979) and were deposited in the entomological collection of the Forest Research Institute.
Ips amitinus developed in branches with a diameter of 5-8 cm, while C. pusillus and P. chalcographusin branches with a diameter 2-4 cm.
In conclusion, it should be noted that the bark beetles and other xylophagous insects of P. peuce in Bulgaria have not been well studied yet. This note is the second record for the trophic association between the three bark beetles and P. peuce. More than 20 species of longhorn beetles (Angelov, 1967;Ganev, 1984Ganev, , 1986Rapuzzi, Georgiev, 2007, etc.) and more than 20 species of jewel beetles (Weidlich, 1988(Weidlich, , 1989Sakalian, 2003, etc.) developing on conifers have been found in Pirin Mts. The Macedonian pine is a potential host for them, therefore more species could be established in future detailed studies.