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The purpose of this study was to identify the species composition of coleopterous predators and their occurrence in different parts of the stem depending on the health condition of Scots pine (<italic>Pinus sylvestris</italic> L.) in the collapsing foci of bark beetles (Coleoptera: Curculionidae: Scolytinae). The research was carried out in 2019–2021 at 38 sample plots located in five State Forestry Enterprises of Sumy region (Ukraine). All sample plots are located in pure Scots pine stands in relatively poor forest site conditions. The relative density of stocking is 0.6–0.7, and the age of stands is between 60 and 110 years. The health condition for each tree was evaluated on visual characteristics by the classes: first – healthy; second – weakened; third – severely weakened; fourth – drying up; fifth – recently died and sixth – died over a year ago. Bark beetles’ nuptial chambers and predators were counted on 25 × 25 cm pallets, which were located at the lower, middle and upper parts of the stem with thin, thick and transitional bark, respectively. The significance of differences in the performance of predator species depending on the tree part, health condition and year was analysed using the nonparametric Kruskal–Wallis (K–W) test. The species composition of predators in different years, stem parts and tree health condition was compared using the Sorensen–Chekanovsky index.
In the collapsing foci of bark beetles, the health condition of Scots pine in 2019–2021 tended to worsen. The infestation density of <italic>Ips acuminatus</italic> (Gyllenhal, 1827) and <italic>Ips sexdentatus</italic> (Boerner, 1767) was 0.62 ± 0.032 and 0.64 ± 0.017 nuptial chambers per 1 dm2, respectively, and also decreased in 2019–2021. In the galleries of bark beetles, seven species of coleopterous predators were collected: <italic>Aulonium ruficorne</italic> (Olivier, 1790) (Zopheridae), <italic>Platysoma elongatum</italic> (Leach, 1817) (Histeridae), <italic>Rhizophagus depressus</italic> (Fabricius, 1792) (Monotomidae), <italic>Corticeus pini</italic> (Panzer, 1799) (Tenebrionidae), <italic>Thanasimus formicarius</italic> (Linnaeus, 1758), <italic>Thanasimus femoralis</italic> (Zetterstedt, 1828) (Cleridae) and <italic>Salpingus ruficollis</italic> (Linnaeus, 1761) (Salpingidae). Two more species – <italic>Glischrochilus quadripunctatus</italic> (Linnaeus, 1758) (Nitidulidae) and <italic>Pytho depressus</italic> (Linnaeus, 1767) (Pythidae) – were singly collected in the foci. <italic>T. formicarius</italic> and <italic>P. elongatum</italic> were the most abundant. The ratio of predator–prey significantly increased from the upper to the lower part of the stem with thick bark. It, however, decreased in this stem part from the fourth to the sixth class of the health condition of the host tree.
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The purpose of this study was to identify the species composition of coleopterous predators and their occurrence in different parts of the stem depending on the health condition of Scots pine (Pinus sylvestris L.) in the collapsing foci of bark beetles (Coleoptera: Curculionidae: Scolytinae). The research was carried out in 2019–2021 at 38 sample plots located in five State Forestry Enterprises of Sumy region (Ukraine). All sample plots are located in pure Scots pine stands in relatively poor forest site conditions. The relative density of stocking is 0.6–0.7, and the age of stands is between 60 and 110 years. The health condition for each tree was evaluated on visual characteristics by the classes: first – healthy; second – weakened; third – severely weakened; fourth – drying up; fifth – recently died and sixth – died over a year ago. Bark beetles’ nuptial chambers and predators were counted on 25 × 25 cm pallets, which were located at the lower, middle and upper parts of the stem with thin, thick and transitional bark, respectively. The significance of differences in the performance of predator species depending on the tree part, health condition and year was analysed using the nonparametric Kruskal–Wallis (K–W) test. The species composition of predators in different years, stem parts and tree health condition was compared using the Sorensen–Chekanovsky index.
In the collapsing foci of bark beetles, the health condition of Scots pine in 2019–2021 tended to worsen. The infestation density of Ips acuminatus (Gyllenhal, 1827) and Ips sexdentatus (Boerner, 1767) was 0.62 ± 0.032 and 0.64 ± 0.017 nuptial chambers per 1 dm2, respectively, and also decreased in 2019–2021. In the galleries of bark beetles, seven species of coleopterous predators were collected: Aulonium ruficorne (Olivier, 1790) (Zopheridae), Platysoma elongatum (Leach, 1817) (Histeridae), Rhizophagus depressus (Fabricius, 1792) (Monotomidae), Corticeus pini (Panzer, 1799) (Tenebrionidae), Thanasimus formicarius (Linnaeus, 1758), Thanasimus femoralis (Zetterstedt, 1828) (Cleridae) and Salpingus ruficollis (Linnaeus, 1761) (Salpingidae). Two more species – Glischrochilus quadripunctatus (Linnaeus, 1758) (Nitidulidae) and Pytho depressus (Linnaeus, 1767) (Pythidae) – were singly collected in the foci. T. formicarius and P. elongatum were the most abundant. The ratio of predator–prey significantly increased from the upper to the lower part of the stem with thick bark. It, however, decreased in this stem part from the fourth to the sixth class of the health condition of the host tree.

Coleopterous predators of pine bark beetles in the last years of the outbreak recorded in Ukraine

Czech University of Life Sciences in Prague

Folia Forestalia Polonica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The purpose of this study was to identify the species composition of coleopterous predators and their occurrence in different parts of the stem depending on...

Coleopterous predators of pine bark beetles in the last years of the outbreak recorded in Ukraine

Article Category: Original Article

Published Online: Sep 22, 2022

Page range: 161 - 172

Received: Mar 17, 2022

Accepted: Jul 08, 2022

DOI: https://doi.org/10.2478/ffp-2022-0016

Keywords
forest, Sumy region of Ukraine, frequency of occurrence, health condition class, nuptial chambers, predator/prey ratios

© 2022 Valentyna Meshkova et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Coleopterous predators of pine bark beetles in the last years of the outbreak recorded in Ukraine

Article Category: Original Article

Published Online: Sep 22, 2022

Page range: 161 - 172

Received: Mar 17, 2022

Accepted: Jul 08, 2022

DOI: https://doi.org/10.2478/ffp-2022-0016

Keywordsforest, Sumy region of Ukraine, frequency of occurrence, health condition class, nuptial chambers, predator/prey ratios

© 2022 Valentyna Meshkova et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
forest, Sumy region of Ukraine, frequency of occurrence, health condition class, nuptial chambers, predator/prey ratios