The four-eyed fir bark beetle Polygraphus proximus Blandf., native in Far Eastern Eurasia and nearby islands, is an invasive pest of fir trees in Siberian and European parts of Russia. Its invasion has been overlooked and was only finally appreciated in 2008.
Subsequently, the scale and area of damage to the forests has increased catastrophically. Thus, extensive monitoring and population control are required to localize and stop any further spread of the invasion.
We used mitochondrial DNA markers to analyze the genetic diversity and population structure of invasive and aboriginal populations of P. proximus, aiming to establish the main sources and corridors of its spread and to infer the history of colonization.
Eighteen haplotypes clustered in five groups were identified. The aboriginal populations had the highest degree of haplotype variability, including almost all haplotypes found in the areas of invasion. The Siberian introduced populations had a sufficient reduction of genetic variation, and a strong geographical partitioning. The European populations mostly had the same haplotypes as the invasive Siberian populations.
The results of the present study support the scenario of P. proximus spreading from the Far East of Russia westward via timber transport along the major Russian railway network.

Genetic diversity of aboriginal and invasive populations of four‐eyed fir bark beetle Polygraphus proximus Blandford (Coleoptera, Curculionidae, Scolytinae)

Invasive alien insects cause serious ecological and economical losses around the world. Here, we review the bionomics, modern ranges (and their dynamics), distribution pathways, monitoring, and control measures of 14 insect species known to be important invasive and emerging tree pests in forest and urban ecosystems of Russia: Leptoglossus occidentalis (Hemiptera: Heteroptera: Coreidae), Halyomorpha halys (Hemiptera: Heteroptera: Pentatomidae), Corythucha arcuata (Hemiptera: Heteroptera: Tingidae), Agrilus fleischeri, A. mali, A. planipennis, Lamprodila (Palmar) festiva (Coleoptera: Buprestidae), Ips amitinus, Polygraphus proximus (Coleoptera: Curculionidae: Scolytinae), Cydalima perspectalis (Lepidoptera: Crambidae), Acrocercops brongniardella, Cameraria ohridella, Phyllonorycter issikii, and P. populifoliella (Lepidoptera: Gracillariidae). We identified three major scenarios of tree pest invasions in the country and beyond: (1) a naturally conditioned range expansion, which results in the arrival of a pest to a new territory and its further naturalization in a recipient region; (2) a human-mediated, long-distance transfer of a pest to a new territory and its further naturalization; and (3) a widening of the pest’s trophic niche and shift to new host plant(s) (commonly human-introduced) within the native pest’s range frequently followed by invasion to new regions.

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Invasive Insect Pests of Forests and Urban Trees in Russia: Origin, Pathways, Damage, and Management

The analysis of my own and published data has made it possible to reveal the main trends of invasions in coleopterans of European Russia. On the whole, 168 alien species of beetles from 30 families have been recorded in the region; 102 of them are pests. The following biotopes are typical for alien beetles of European Russia: houses, agrocenoses, biocenoses of human settlements, and ruderal biotopes. However, more than 50% of species occur in their native biotopes: forests, animal shelters, etc. No species has drastically changed native communities, but species of tree pests, which penetrated recently from East Asia, can potentially inflict serious damage to the forests of European Russia: Agrilus planipennis (Buprestidae), Trichoferus campestris (Cerambycidae), Anisandrus maiche (Curculionidae, Scolytinae), Xyleborinus attenuatus (Curculionidae, Scolytinae), and Xylosandrus germanus (Curculionidae, Scolytinae). About half of these species were accidentally introduced with products of either animal or plant origin, about 25% of them were transported with plant substrates (straw, compost), about 10% came with wood, about came 14% with living plants, and less than 5% of species were introduced intentionally. The native ranges of alien beetles of European Russia are situated in the Mediterranean region, East and Southeast Asia, Central Asia, Africa, South and North America, Western Europe, and Australia. The highest number of species (about 20%) originate from East Asia. Most alien beetles were introduced to European Russia not directly, but rather from Western Europe (invasion in stages). In the last 20 years, the number of new alien species originating from East Asia has increased. The regions in which the majority of new beetle species alien to European Russia have been found over the last 20 years are Krasnodar krai and Adygea (14 species) and Moscow oblast (8 species). The process of invasion of beetles into European Russia is accelerating. More alien beetles have penetrated into European Russia during the last 20 years than in the same periods in the past: 42 new alien species, including 23 pest species. The percentage of new alien species associated with living plants has been constantly increasing since the middle of the 20th century and has reached more than 50% in the last 20 years. Alien beetles typically have wide ranges. About 80% of alien beetle species of European Russia have adapted not only in Europe but also in other parts of the world; more than 50% of them have become cosmopolitan. The distribution of an alien species is usually fast: such a species spreads thousands of kilometers in several decades.

Main trends of invasion processes in beetles (Coleoptera) of European Russia

Conifer decline (Abies sibirica Ledeb. stands) as a result of complex biotic effects on the territory of Krasnoyarsk krai by 2018 reached an area of 541 400 ha; the potential area of further death of A. sibirica is up to 10 million ha. The main reason is the phytopathogenic fungi Armillaria mellea s.l. and Heterobasidion annosum s.l. combined with bark beetle Polygraphus proximus. Trees affected by root pathogens are centers of forest dieback, from which pathological outbreaks spread, including the effects of P. proximus and its phytopathogenic mycoassociates. Neonectria fuckeliana (C. Booth) Castl & Rossman is among the concomitant pathogens in the scale of the lesion, which causes a resin flow that is similar to the effects of P. proximus attack. The phytopathogenicity of pure cultures of the dominant root pathogens of Armillaria borealis Marxm. & Korhonen and Heterobasidion annosum (Fr.) Bref., as well as the stem pathogen of N. fuckeliana, has been confirmed by a series of experiments in vitro. Promising natural agents for the regulation of P. proximus abundance are highly virulent aboriginal strains of Beauveria bassiana (Bals.–Criv.) Vuill., resulting in maximum insect death (up to 100%) for 7–11 days and retaining activity in the temperature range of 16–24 ± 1°C.

Mass Reproduction of Polygraphus proximus Blandford in Fir Forests of Siberia Infected with Root and Stem Pathogens: Monitoring, Patterns, and Biological Control

Biological diversity is the basis for, and an indicator of biosphere integrity. Together with climate change, its loss is one of the two most important planetary boundaries. A halt in biodiversity loss is one of the UN Sustainable Development Goals. Current changes in biodiversity in the vast landmass of Siberia are at an initial stage of inventory, even though the Siberian environment is experiencing rapid climate change, weather extremes and transformation of land use and management. Biodiversity changes affect traditional land use by Indigenous People and multiple ecosystem services with implications for local and national economies. Here we review and analyse a large number of scientific publications, which are little known outside Russia, and we provide insights into Siberian biodiversity issues for the wider international research community. Case studies are presented on biodiversity changes for insect pests, fish, amphibians and reptiles, birds, mammals and steppe vegetation, and we discuss their causes and consequences.

Impacts of environmental change on biodiversity and vegetation dynamics in Siberia.

The role of Polygraphus proximus Blandf., an invasive bark beetle of Far Eastern origin, in the transformation of taiga ecosystems of the plains of Western Siberia is evaluated. It is shown that this species is currently one of the main factors of degradation of the Siberian fir forests and various changes in their ecosystems. The consequences of invader outbreaks in fir forests of the region are massive mortality of forest stands, reduction in the number of and deterioration in the vitality of fir undergrowth, and significant changes in the species composition and structure of the vegetation cover and xylophilous insect fauna.

Transformation of taiga ecosystems in the Western Siberian invasion focus of four-eyed fir bark beetle Polygraphus proximus Blandford (Coleoptera: Curculionidae, Scolytinae)

E. N. Pats

Papers

Transformation of taiga ecosystems in the Western Siberian invasion focus of four-eyed fir bark beetle Polygraphus proximus Blandford (Coleoptera: Curculionidae, Scolytinae)

Small spruce bark beetle as a new challenge for forest protection in siberia