FINDING OF THE BARK BEETLE POLYGRAPHUS PROXIMUS BLANDFORD, 1894 (COLEOPTERA, CURCULIONIDAE: SCOLYTINAE) IN UDMURTIA

The data on the first finds in the Udmurt Republic (and the East of European Russia as a whole) of a dangerous invasive species of bark beetle of the Far Eastern origin - Polygraphus proximus Blandford, 1894, are presented. The species was discovered in 2019 simultaneously in four districts (Zavyalovsky, Malopurginsky, Kiyasovsky and Sarapulsky) of the central and southern parts of the republic. The established areas damaged by the Polygraphus proximus of forest stands are located both near railway tracks and highways, and in the depths of natural forests in which Siberian fir grows ( Abies sibirica Ledeb.), which indicates a long-term hidden invasion of the pest and its adaptation in Udmurtia. Further outbreak of the pest can lead to catastrophic consequences for forests with the participation of fir in the region. In addition, in the stands damaged by the Polygraphus proximus , an increase in the number of local species of longhorn beetles, associated with fir, is possible. In connection with the extreme potential harmfulness of this invader, it is necessary to carry out sanitary and recreational activities in order to localize and eliminate the identified outbreak foci of the pest, as well as to clarify the forest areas occupied by the Polygraphus proximus in the territory of the Udmurt Republic and adjacent regions, with introduction of quarantine and monitoring measures.

Distribution pattern of entry holes of the tree-killing bark beetle Polygraphus proximus

Bark beetles attack their hosts at uniform intervals to avoid intraspecific competition in the phloem. Bark texture and phloem thickness also affect bark beetle attacks, and the bark characteristics are not spatially homogeneous; therefore, the distribution patterns of entry holes can demonstrate an aggregated distribution. Polygraphus proximus Blandford (Coleoptera: Scolytinae) is a non-aggressive phloephagous bark beetle that feeds on Far Eastern firs. They have caused mass mortality in Russia and Japan. However, the distribution pattern of entry holes of P. proximus and spatial relationships with bark characteristics have not been studied. Thus, we investigated the distribution pattern of entry holes of P. proximus. The distribution of entry holes was significantly uniform in most cases. As the attack density increased, an aggregated distribution pattern within a short distance (< 4.0 cm) was observed. The rough bark had a significantly higher number of entry holes than the remaining bark. The distribution pattern of entry holes demonstrated a significantly aggregated spatial association with rough bark. Finally, rough bark around knots had significantly thicker phloem than the remaining barks. These suggest that P. proximus may preferentially attack rough bark to reproduce in the thicker phloem under a rough bark surface.

Principles for assessing forest management risks associated with natural hazards

Subject. This article examines the risks associated with the loss of ecological and resource potential of forests, and those affecting timber harvesting activities. Objectives. The article aims to develop and test methodological approaches and principles for assessing risks to certain forest management types associated with natural hazards. Methods. For the study, we used the methods of general scientific research, statistical, comparative, logical, and geoinformation analyses. Results. The article presents a developed method of calculating the environmental and economic damage to the fir forests of Western Siberia as a result of the invasion of bark beetles, Polygraphus proximus Blandford. It describes the main natural factors that disrupt the operation of special equipment and the conditions for harvested wood transportation and assesses the most likely risks of logging activities in winter. The testing of a comprehensive assessment of forest risks at the regional level shows the region's area differences in terms of risk both for individual natural hazard factors and in their totality. Conclusions. Forest management risk analysis can be successfully implemented through using methods based on general scientific principles. Specially designed approaches should be used to address narrowly focused industry challenges.

POSSIBILITIES OF GIS FOR STUDYING THE PROCESSES OF DISTRIBUTION OF THE USSURIYSK POLYGRAPH IN THE FIR FORESTS OF SIBERIA

In recent decades, the Siberian fir forests have been seriously damaged by the invasive bark beetle of Far Eastern origin, the Ussuri polygraph Polygraphus proximus Blandf. The damage from the impact of the pest is expressed in monetary value and in the loss of many ecological functions of forest ecosystems. Technologies for organizing ground monitoring of the spread of the pest are successfully tested by Siberian scientists, and with the involvement of GIS technologies, they can provide a spatio-temporal analysis of the scale of the negative processes occurring. The purpose of this article is to show the capabilities of GIS technologies in combination with remote sensing in studying the processes of invasion of the Ussuri polygraph using the example of forest areas in the Tomsk region. It is shown that the geoinformation approach to the study of the fir forests state in the centers of mass reproduction of the pest makes it possible to create a series of thematic maps reflecting large-scale spatial and temporal changes in plantations and to give a short-term forecast of the development of the centers. The high efficiency of this approach is shown in the local analysis of the centers’ development and to assess the dynamics of mass reproduction of the pest at the forestry level. Based on the built-in analytical information and cartographic display, it becomes possible to predict the emergence of new centers, monitor and control their development.

Mating Systems of the Tree-Killing Bark Beetle Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae)

Polygraphus proximus Blandford (Coleoptera: Curculionidae: Scolytinae) has caused mass mortality of fir (Abies spp. (Pinaceae)) forests across large areas of Russia in the past decade. More recently, mass mortality of A. veitchii Lindl. due to P. proximus infestation has been reported in Japan. This bark beetle species traditionally has been considered to be polygynous because their galleries have multiple gallery arms, and because harem-polygyny is common in the tribe Polygraphini. Although the mating system(s) potentially could have a marked effect on their reproductive success and population dynamics, the reproductive behavior of the tree-killing bark beetle P. proximus has not been investigated in detail in a natural setting in Japan. We, therefore, investigated the number of males and females in a gallery and the number of gallery arms in Abies species in Japan. None of the galleries examined contained more than one male, and 57.2% of the galleries had multiple gallery arms, even though only 2.8% of the galleries contained two females. The findings showed that the typical mating system employed by P. proximus is monogyny and that this species constructs multiple gallery arms in each gallery. In addition, 70.4% of galleries in which the sex of adult beetles could be determined contained no males, and 26.6% contained no females, suggesting that P. proximus males and females re-emerge.

Sex-Specific Wolbachia Infection Patterns in Populations of Polygraphus proximus Blandford (Coleoptera; Curculionidae: Scolytinae)

Wolbachia symbionts are maternally inherited bacteria that are widely distributed among Arthropoda hosts. Wolbachia influence their host biology in diverse ways. They may induce reproductive abnormalities, protect hosts against pathogens and parasites, or benefit hosts through metabolic provisioning. The progeny of an infected female are ordinarily infected with Wolbachia; however, Wolbachia have no future in male host progeny because they cannot transmit the symbiont to the next generation. Here, we analyze native and invasive populations of the four-eyed fir bark beetle (Polygraphus proximus) for Wolbachia prevalence and symbiont genetic diversity. This species is a dangerous pest of Siberian fir (Abies sibirica) forests. The native range of P. proximus includes the territories of the Russian Far East, Japan, Korea, and Northeast China, whereas its invasive range includes West Siberia, with further expansion westward. Surprisingly, we revealed a difference in the patterns of Wolbachia prevalence for males and females. Infection rate and Wolbachia titers were higher in females than in males. ST-533, the only haplotype of Wolbachia supergroup B, was associated with a minimum of three out of the five described mitochondrial haplotypes.

STATE OF DARK CONIFEROUS FORESTS IN THE SPECIALLY PROTECTED NATURAL AREAS OF THE TOMSK OBLAST IN THE INVASION ZONES OF ALIEN SPECIES OF BARK BEETLES

The state of dark coniferous stands located in specially protected natural territories of the Tomsk Oblast in the invasion zone of four-eyed fir bark beetle Polygraphus proximus Blandford and small spruce bark beetle Ips amitinus Eichhoff is described.