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• The red turpentine beetle (RTB) has infested large areas of pines in North China. • Environmental factors played diverse roles at different stages of RTB infestation. • At the incipient stage, RTB damag. • e was mainly related to stand-level factors. • At the epidemic stage, RTB damage was mainly related to landscape-level factors. The red turpentine beetle (RTB), an invasive pest species, has infested large areas of pine forests and caused extensive tree mortality in North China. The ensuing substantial economic and ecological losses make understanding the development and spread of RTB infestations critical. Although some studies have postulated how multiple factors affect bark beetle damage at different stages of population development, knowledge about this mechanism from empirical research is still limited. In recent years, RTB infestations in Heilihe Town of Inner Mongolia and Dahebei Town of Liaoning Province were at different phases (incipient and epidemic stages), which allowed us to explore the possible change mechanism of influencing factors. The present study aimed to identify the critical factors influencing RTB damage and determine whether the primary influencing factors changed during different RTB infestation stages. We established 42 and 40 sample plots in the Heilihe and Dahebei areas and measured the sample plots' canopy cover, slope, aspect, average diameter at breast height (DBH), elevation and RTB attack rate. Sentinel-2 images and trap data were used to obtain landscape-level variables, including host area, edge density and beetle pressure. We then developed generalized linear models to determine the impact of these explanatory variables on RTB damage. Our results found that the average RTB attack rate of the incipient and epidemic areas was, respectively, 5.35% and 31.45%. At the incipient stage, RTB infestations were mainly related to stand-level factors, including canopy cover and aspect. However, at the epidemic stage, RTB infestations were associated with stand (DBH) and landscape-level factors, in which host area and beetle pressure played an important role. Stand and landscape-level factors played diverse roles during different periods of RTB infestations. Such findings are valuable for understanding the colonization pattern of RTB and taking appropriate management interventions in different infestation stages. [ABSTRACT FROM AUTHOR]

Monochamus saltuarius (Coleoptera: Cerambycidae) was reported as the vector beetle of the pine wood nematode (PWN, Bursaphelenchus xylophilus) in Japan and Europe. It was first reported to transmitted the PWN to native Pinus species in 2018 in Liaoning Province, China. However, the lack of genomic resources has limited the in-depth understanding of its interspecific relationship with PWN. Here, we obtained a chromosome-level reference genome of M. saltuarius combining Illumina, Nanopore and Hi-C sequencing technologies. We assembled the scaffolds into ten chromosomes (including an X chromosome) and obtained a 682.23 Mb chromosome-level genome with a N50 of 73.69 Mb. In total, 427.67 Mb (62.69 %) repeat sequences were identified and 14, 492 protein-coding genes were predicted, of which 93.06 % were annotated. We described the mth / mthl , P450, OBP and OR gene families associated with the vector beetle's development and resistance, as well as the host selection and adaptation, which serve as a valuable resource for understanding the host adaptation in insects during evolution. This high quality reference genome of M. saltuarius also provide new avenues for researching the mechanism of this synergistic damage between vector beetles and PWN. • This research assembled the first chromosomal-level reference genome of Monochamus saltuarius. • The sex chromosome was identified. • Inferred the evolutionary relationship of currently sequenced Coleoptera species. • The contraction and expansion of gene families associated with the insect host adaptation were explored. • We identified the most methuselah/methuselah-like genes associated with insect development and lifespan in M. saltuarius. [ABSTRACT FROM AUTHOR]