Browsing by Author "Meshkova, Valentyna"
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Item Coleopterous predators of pine bark beetles in the last years of the outbreak recorded in Ukraine(Sciendo (De Gruyter), 2022-09-22) Meshkova, Valentyna; Vorobei, Alla; Omelich, AnastasiyaThe 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), Platy soma 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.Item Diprion pini L. (Hymenoptera, Symphyta, Diprionidae) population dynamics in the Low Dnieper region(Sciendo (De Gruyter), 2019-05-04) Meshkova, Valentyna; Nazarenko, Serhii; Kolienkina, MarynaPine sawflies (Hymenoptera, Symphyta, Diprionidae) are the most spread foliage browsing insects of pine forests in Europe, especially monovoltinous European pine sawfly Neodiprion sertifer (Geoffroy, 1785) and common pine sawfly Diprion pini (Linnaeus, 1758), which develops in one or two generations per year depending on weather. The outbreaks of both pine sawflies are the most frequent and intensive in the Steppe zone of Ukraine, especially in the Low Dnieper region, where pine forest (Pinus sylvestris Linnaeus and Pinus pallasiana D. Don) was planted on moving sands in the sixties of the 20th century. This research is aimed at the evaluation of the parameters for D. pini outbreak dynamics in the Low Dnieper region. Outbreak severity, specific foci area and mean score of stand threat by D. pini were evaluated from the regional statistical reports. In the regional scale for 1979–2017, notable outbreaks of D. pini were registered in 1982, 1993, 2002, 2006 and 2017. An interval between maximums was from 4 to 11 years, in average 9 years. The growth of foci area in 1979–1998 as compared to 1999–2017 as well as correlation between pine stand area and annual area of this pest’s foci in different forests was not statistically significant. Graphical analysis of dynamics of D. pini focal area for 2010–2017 was done based on individual threat levels. Our study confirms the fact of three outbreaks for this period in three forest and hunting enterprises (FHE), two outbreaks in one FHE and one outbreak in one FHE. An interval between the outbreaks makes three or six years. The causes of such shortening of interval are discussed.Item Harmfulness of xylophagous insects for silver birch (Betula pendula Roth.) in the left-bank forest-steppe of Ukraine(Sciendo (De Gruyter), 2019-10-07) Skrylnik, Yuriy; Koshelyaeva, Yana; Meshkova, ValentynaThe aim of the research was to determine the rate of the damage of xylophagous insects for silver birch (Betula pendula Roth.) stands in the Left Bank Forest-steppe of Ukraine. Evaluation of physiological harmfulness considered a health condition of inhabited trees, features of maturating feeding and pathogens vectoring for the cases of so-called ‘provoked aggressiveness’ and its absence. Evaluation of technical harmfulness considered a location and depth of larval galleries and pupal chambers, colonized sapwood surface, and stem part. Evaluation of general harm fulness considered physiological harmfulness, technical harmfulness and generation number. Among 22 xylophagous insect species, 4 species were widespread (Agrilus viridis (Linnaeus, 1758), Xylotrechus rusticus (Linnaeus, 1758), Xyleborinus saxeseni (Ratzeburg, 1837), and Xyleborinus attenuatus (Blandford, 1894)); 3 species were common, 6 species were rare and 9 species were single. The highest physiological harmfulness is expected for Tremex fuscicornis (Fabricius, 1787) and Tremex magus (Fabricius, 1787), Сhrysobothris affinis (Fabricius, 1774), Agrilus viridis (Linnaeus, 1758), Xylotrechus rusticus, and bark beetles. The highest technical harmfulness is expected for wood wasps – Tremex spp., jewel beetles Dicerca furcata (Thunberg, 1787) and Dicerca alni (Fischer von Waldheim, 1824), longhorn beetle Xylotrechus rusticus, and xylomycetophages – Xyleborinus sp. All widespread species are evaluated by a wide range of physiological harmfulness. Three of them (all except Agrilus viridis) are evaluated by highly technical harmfulness and from moderate to highly general harmfulness. Among the species having a common occurrence, Tremex fuscicornis can be highly harmful only in the case of tree weakening by negative factors, another two species can be non-harmful, and Xiphydria longicollis (Geoffroy, 1785) can be low harmful in the case of tree weakening by negative factors. Among the rare species, Scolytus ratzeburgi Janson, 1856 can be low or moderately harmful and Tremex magus can be low or highly harmful depending on the presence or absence of other negative factors. Among single species, Zeuzera pyrina (Linnaeus, 1761) can be moderately harmful because it colonizes almost healthy trees. The rest three species can be moderately harmful in the case of tree weakening by negative factors.Item Xylophagous beetles (Coleoptera) in the zones of Gomilshanski lisy National Nature Park with different management regime(Sciendo (De Gruyter), 2022-05-27) Meshkova, Valentyna; Skrylnik, Yuriy; Bieliavtsev, Maxim; Zinchenko, Olga; Borysenko, Oleksandr; Markina, TetianaThe purpose of the research was to assess the species composition and biodiversity indices for xylophagous beetles collected by window traps in the parts of Gomilshanski lisy National Nature Park with different management regimes and anthropogenic load. Four window traps were placed in each of the five groups of sample plots: clear felling, selective felling, stationary recreation, regulated recreation and protected zone. The data were analysed using the statistical software package PAST, particularly, the Menhinick index (DMn) and dominance index (D) were evaluated and classical clustering (unweighted pair-group average [UPGMA]) was performed. A total of 42 species of xylophages (9903 individuals) were collected from Curculionidae (Scolytinae and Cossoninae), Cerambycidae, Histeridae, Bostrichidae, Buprestidae and Lymexilidae. The highest species richness was in the plots of clear and selective felling (25 and 22 species, respectively) and the lowest was in the protected zone (16 species), regulated recreation (19 species) and stationary recreation (22 species). The Menhinick index (DMn) was the lowest in the protected zone (0.27), increased in the zone of regulated recreation (0.43) and stationary recreation (0.45) and was maximal in the plots of selective and clear felling (0.69 and 0.77, respectively). The number of individuals was maximal in the protected zone and minimal at the plots of selective and clear felling. All sites were dominated by Xyleborinus saxesenii (Ratzeburg, 1837) (66–85% individuals) and Anisandrus dispar (Fabricius, 1792) (8.5–20.7% individuals). Minimal dominance (0.49) was found in the plot of clear felling. Cluster analysis showed similarity of the xylophage complex in the plots of clear and selective felling, as well as in the zone of stationary and regulated recreation, which differed from the protected zone.