Search

Diplogyniopsis fluctuosumsp. nov. associated with passalid beetles is described based on females from China on undermined passalid beetles, as well as on females and males from Thailand on Aceraius helferi (Coleoptera: Passalidae). The species represents the second known species of Diplogyniopsis Trägårdh, prompting us to redefine the genus diagnosis. [ABSTRACT FROM AUTHOR]

Simple Summary: Three bark beetle species, Tomicus yunnanensis, T. brevipilosus, and T. minor, are the most economically significant pests of the Yunnan pine in Southwestern China. Chemical and physical communication play key roles in various life activities. In this study, we described the fine structure of the adult mouthparts of these three Tomicus species using scanning and transmission electron microscopy. We identified three types of mandibular shapes, which match with their biomechanical properties, their ability to process food, and their preferred foraging locations on tree trunks. Eleven types of sensilla were discernible, including sensilla basiconica, sensilla twig basiconica, sensilla coeloconica, sensilla chaetica, sensilla trichoidea, and sensilla digitiformia. The function roles of each sensilla type were given based on its distribution and structures, especially on the internal structures such as dendrites and tubular body. Most chemoreceptors occur on the palpal tips. No significant differences among the sexes or species were identified; however, intraspecific variability in the number of sensilla twig basiconica 3 and sensilla digitiformia sensilla was evident. These findings will aid future studies of the feeding niches and reproductive behaviors of Tomicus beetles. Tomicus yunnanensis, T. brevipilosus, and T. minor are the most economically significant pests of Pinus yunnanensis in Southwestern China. Chemical and physical factors play critical roles in diverse biological activities. Here, we describe the fine structure of the adult mouthparts of these three Tomicus species using scanning and transmission electron microscopy. We identified three types of mandibular shapes, which determine their biomechanical properties, their ability to process food, and their preferred foraging locations on tree trunks. Eleven types of sensilla were discernible, including sensilla basiconica (Sb.1–2), sensilla twig basiconica (Stb.1–3), sensilla coeloconica (Sco), sensilla chaetica (Sch.1–2), sensilla trichoidea (Str.1–2), and sensilla digitiformia (Sdi). Each basiconic sensillum occurs on the palpal tips and is innervated by 2–6 dendrites. Sb.1 are gustatory receptors, Sb.2 are olfactory receptors, and the three other sensilla have dual taste and mechanical functions. Sco, Sch, and Str are mechanoreceptors. Sdi are mechanical vibration receptions, given that they are innervated by one dendrite with numerous dendritic branches into the nonporous cuticle. No significant differences among the sexes or species were identified; however, intraspecific variability in the number of Stb.3 and Sdi sensilla was evident. These results will aid future studies of Tomicus beetle behaviors. [ABSTRACT FROM AUTHOR]

Three new species of the genus Chrysolina Motschulsky, 1860, namely Ch. caspari sp. n., Ch. melchiori sp. n., and Ch. balthazari sp. n. are described from Sichuan and Yunnan Provinces of China. These species have rare or unique features. In Ch. caspari sp. n. the shape of the last maxillary palpomere (it is shorter and narrower than the penultimate one) is a rare case in the genus Chrysolina. Among Chinese species, this shape of maxillary palpi is known only in one species, Ch. pieli Chen, 1936. In Ch. melchiori sp. n. the relief of elytral surface (strongly reticulated irregular funnels bearing a puncture at the bottom, separated by smooth intervals) is unique for the genus Chrysolina. In Ch. balthazari sp. n. the relief of elytra (alternation of wide convex intervals between pairs of rows and very narrow flat or slightly convex intervals between rows of one pair) is well distinguishable from most Chrysolina members. Due to this feature, the new species can only be close to Ch. jinxiaoae Ge in: Daccordi, Ge, Cui, Yang, 2011 from North Sichuan. Photographs of habitus, external characters, and male aedeagi are presented. [ABSTRACT FROM AUTHOR]

Simple Summary: Tomicus minor (Hartig) and Tomicus yunnanensis Kirkendall and Faccoli are two sympatric species that infest Pinus yunnanensis (Franchet) in southwest China. Sound knowledge of the two pine shoot beetles' distribution within P. yunnanensis is needed to formulate accurate sampling methods. Three pine forests with different experimental sites in Yuxi, Yunnan province, China were investigated from 2016 to 2018. Field counts were modeled in various spatial models, and it was determined that two species adults showed aggregated spatial distributions. A fixed-precision sampling plan showed that, for a D of 0.25 and 0.10, sample sizes of 41 plants and 259 plants for T. minor and 33 plants and 208 plants for T. yunnanensis were adequate, respectively. This sampling program could be useful for the integrated pest management of two sympatric Tomicus species. Tomicus minor (Hartig) and Tomicus yunnanensis Kirkendall and Faccoli are two sympatric species that infest Pinus yunnanensis (Franchet) in southwest China, contributing to growth losses. Accurate sampling plans are needed to make informed control decisions for these species. We investigated three pine forests within experimental sites in Yuxi, Yunnan province, China from 2016 to 2018. The spatial distribution patterns of two pine shoot beetles during the shoot-feeding phase were determined using Taylor's power law. The optimum sample sizes and stop lines for precision levels of 0.25 and 0.10 were calculated. The model was validated using an additional 15 and 17 independent field datasets ranging in density from 0.06 to 1.90 beetles per tree. T. minor and T. yunnanensis adults showed aggregated spatial distributions. For T. minor, sample sizes of 41 and 259 trees were adequate for a D of 0.25 and 0.10, respectively, while for T. yunnanensis, a mean density of one individual per tree required sample sizes of 33 plants (D = 0.25) and 208 plants (D = 0.10). The software simulations of this sampling plan showed precision levels close to the desired levels. At a fixed-precision level of 0.25, sampling is easily achievable. This sampling program is useful for the integrated pest management (IPM) of two sympatric Tomicus species. [ABSTRACT FROM AUTHOR]

A new subgenus of the genus Chrysolina Motschulsky, 1860, endemic to Yunnan Province of China, Ch. (Volosatik subgen. nov.) is described. All species inhabit highland forests. Seven species, including four species new to science, are recognized: Chrysolina fascinatrix Lopatin, 1998, Ch. liqingzhaoae Daccordi et Ge, 2011, Ch. wangi Lopatin, 2005, Ch. igori sp. nov., Ch. marinae sp. nov., Ch. genriki sp. nov., and Ch. ilyakabaki sp. nov. The representatives of this new subgenus are characterised by a small, broadly oval, convex, shining body with metallic dorsum, with maxillary palpus narrow, similar in both sexes, with pronotal lateral impressions wide and shallow or obsolete, without numerous large punctures, with elytral puncture rows paired, mostly regular, intervals flat, with tarsomeres 1–3 with entire sole, rather narrow in both sexes, with aedeagus bearing sensilla of different types ventro-laterally near apex, flagellum narrow. Photographs of habitus and male aedeagus are presented. [ABSTRACT FROM AUTHOR]

A new species of Scaphobaeocera Csiki, 1909 from Yunnan, China, S. setosa sp. nov., is described. It is unique in having strongly enlarged male protarsomeres with long oblique setae, forming a fan-like structure. The new species may be also readily distinguished from its congeners by its large body size. [ABSTRACT FROM AUTHOR]

Outbreaks of pine shoot beetles (Tomicus spp.) have caused widespread tree mortality in Southwest China. However, the understanding of the role of climatic drivers in pine shoot beetle outbreaks is limited. This study aimed to characterize the relationships between climate variables and pine shoot beetle outbreaks in the forests of Yunnan pine (Pinus yunnanensis Franch) in Southwest China. The pine shoot beetle-infested total area from 2000 to 2017 was extracted from multi-data Landsat images and obtained from field survey plots. A temporal prediction model was developed by partial least squares regression. The results indicated that multi consecutive year droughts was the strongest predictor, as such a condition greatly reduced the tree resistance to the beetles. The beetle-infested total area increased with spring temperature, associated with a higher success rate of trunk colonization and accelerated larval development. Warmer temperatures and longer solar radiation duration promoted flight activity during the trunk transfer to the shoot period and allowed the completion of sister broods. Multi consecutive year droughts combined with the warmer temperatures and higher solar radiation duration could provide favorable conditions for shoot beetle outbreaks. Generally, identifying the climate variables that drive pine shoot beetle outbreaks could help improve current strategies for outbreak control. [ABSTRACT FROM AUTHOR]

Two new species, Helochares guoi Yang & Jia, sp. nov. and Helochares distinctus Jia & Tang, sp. nov., are described. Two species are recorded for the first time from China: Helochares negatus Hebauer, 1995 from Yunnan, and Helochares minusculus d'Orchymont, 1943 from Guangdong. Additional faunistic data from China are provided for the following species: Helochares hainanensis Dong & Bian, 2021, Helochares nipponicus Hebauer, 1995, Helochares sauteri d'Orchymont, 1943, Helochares densus Sharp, 1890, Helochares lentus Sharp, 1890, Helochares neglectus (Hope, 1854) and Helochares anchoralis Sharp, 1890. The Chinese fauna of Helochares comprises 16 species, 11 of which are illustrated in this contribution. Helochares crenatus Régimbart, 1921 is removed from the Chinese fauna. [ABSTRACT FROM AUTHOR]

The members of the Megarthrus hemipterus species complex occurring in China, i.e., M. dentipes Bernhauer, M. flavolimbatus Cameron and M. hemipterus (Illiger), are diagnosed, and a new species attributed to this informal group, M. panda sp. nov., is described from Yunnan Province. All species are diagnosed and illustrated, and their distribution in mainland China is mapped. The limit of the M. hemipterus species complex is refined morphologically. [ABSTRACT FROM AUTHOR]

A new species of Pachypaederus Fagel, 1958, P. kongshuhensis Li, sp. nov., is described from Yunnan Province, China. This species represents the third member of the genus from the Oriental region. Color plates of the habitus, labrum, mandibles, sternites VII-IX of the male and female, as well as the aedeagal structures are provided. A key to Oriental Pachypaederus species is provided. [ABSTRACT FROM AUTHOR]

After a century since the erection of the genus Manipuria from India, its type species M. dohertyi Jacoby was discovered in Yunnan Province of China. A new Manipuria species, M. yuae sp. nov., is described from Tibet and Yunnan, China. The new species differs from M. dohertyi by its larger size, unicolored elytra, and absence of a tooth-like prolongation in front of the mandible. Additional data is provided for M. dohertyi based on new material from China. [ABSTRACT FROM AUTHOR]

Bark beetle galleries are complex ecosystems where many microbes and other arthropods co-exist with the beetles. Fungi isolated from these galleries are often referred to as 'beetle associates', but the nature of these associations are poorly understood. The possibility that many of these fungi might in fact be mite associates is often overlooked. Several recent studies explored the diversity of fungi from conifer-infesting bark beetles and their galleries in China, but only one study considered phoretic mites and their fungi from conifer-infesting bark beetles in Yunnan, southwestern China. We studied the mites and fungi from galleries of four spruce-infesting bark beetle species in the high altitude forests of Qinghai province, western China. Mites were identified based on morphological characteristics, and fungi based on DNA sequences of four gene regions. In total, 173 mite individuals were collected belonging to 18 species in 11 genera. A total of 135 fungal isolates were obtained from the mites, representing 14 taxa from the Ophiostomatales. The most frequently isolated fungus was Ophiostoma nitidum, which represented 23.5% of the total isolates. More fungal species were found from fewer mites and bark beetle species than from the study in Yunnan. Although we could not elucidate the exact nature of interactions between mites and their fungi, our results re-enforce that these organisms should not be ignored in pest risk assessments of bark beetles, that often focus only on the beetles and their fungi. Three new species are described: Grosmannia zekuensis, O. manchongi, and O. kunlunense spp. nov., and our data revealed that O. typographi, recently described from China, is a synonym of O. ainoae. [ABSTRACT FROM AUTHOR]

The genus Cyanopenthe Nikitsky, 1998 is first recorded from mainland China. Two new species, C. granulata sp. nov. and C. hirtiscutellara sp. nov., are described and illustrated. This genus is redefined, and an updated key to the known species is presented. [ABSTRACT FROM AUTHOR]

Two new species of the genus Yunnanomonticola Telnov, 2002 are described based on the specimens collected in China. Yunnanomonticola latissima sp. n. is collected from Yunnan and Y. tenuipenis sp. n. is from Guizhou. Photographes of the new species are provided, with a key to the three species of Yunnanomonticola. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Philomyceta biwenxuani sp. nov., a new species from China: Xizang: Motuo County, is described. Additional specimens of P. asperipennis Schillhammer, 2012 are examined from China: Yunnan, including the first record of females. Females of an additional unidentified species are recorded from China: Xizang: Nielamu County. The key to species of Philomyceta Cameroon, 1944 is updated. [ABSTRACT FROM AUTHOR]

This is the first part of a series dealing with the taxonomy of the genus Sathytes Westwood from China. Fifteen Chinese species are recognized and all described here as new: Sathytes cristatus sp.nov., Sathytes excertus sp.nov., Sathytes perpusillus sp.nov., Sathytes rarus sp.nov., Sathytes tangliangi sp.nov., Sathytes tibialis sp.nov., Sathytes usitatus sp.nov. and Sathytes yunanicus sp.nov. from Yunnan; Sathytes larinus sp.nov. and Sathytes wuyishanus sp.nov. from Fujian; Sathytes longitrabis sp.nov. from Shaanxi; Sathytes longwangshanus sp.nov. and Sathytes paulus sp.nov. from Zhejiang; Sathytes magnus sp.nov. from Xizang; and Sathytes sichuanicus sp.nov. from Sichuan. Illustrations of major diagnostic characters of the new species are given. A total of 33 species worldwide are placed into seven newly defined groups. A checklist of Sathytes is also provided. [ABSTRACT FROM PUBLISHER]

Two new species of the genus Nazeris Fauvel collected from Nabanhe Nature Reserve, Yunnan Province, are described under the names of N. nabanhensis sp. n. and N. caoi sp. n. Th e male sexual characters are described and illustrated. A key to the Nazeris species of Yunnan is provided. A map of the collecting sites is given. [ABSTRACT FROM AUTHOR]

A new species of the goliathine genus Bietia Fairmaire, 1898, B. naxiorum sp. nov., is described from the mountains in northwestern Yunnan (China). It is compared with two other species of the genus known so far, B. rudicollis Fairmaire, 1898 and B. simillima Fairmaire, 1898. The folloving new synonymy is proposed: Bietia rudicollis Fairmaire, 1898 = Atropinota funkei Heller, 1923, syn. nov. A lectotype is designated for A. funkei. Dorsal habitus and diagnostic characters on the male external genitalia of all three species of Bietia are illustrated. A diagnosis of the genus and a key to species are provided. The systematic position of Bietia among the known genera of the Oriental and Palaearctic Goliathini is shortly discussed. A brief description of the habitat of B. naxiorum sp. nov. as well as notes on its ground-dwelling habits are given; a ground-dwelling behaviour of adults is recorded for the first time in the Asian Goliathini. [ABSTRACT FROM AUTHOR]

The rare genus Awas Löbl, 1994 is reported from mainland China for the first time, based on a new species, A. sinicus Yin & Li sp. nov., from Yunnan Province. The new species is described and illustrated. It appears closely related to A. shunichii Nomura, 1995 from Taiwan. A revised key to all species is provided. [ABSTRACT FROM AUTHOR]

Background: Flowers are one of the important microhabitats promoting beetle diversity, but little is known about variation in the diversity of these insects at higher elevations. We do not know how divergent habitats influence the distribution of beetles among montane flora. Methods: We sampled beetles systematically in angiosperm flowers at 12 sites at two elevations (2700 m and 3200 m) and in two habitats (meadows and forests) for two consecutive years (2018 and 2019) on the Yulong Snow Mountain in Yunnan, southwestern China. Beetle diversity among sites were compared. Their interactions with flowers of identified plant species were analyzed using bipartite networks approach. Results: We collected 153 species of beetles from 90 plant species recording 3391 interactions. While plant species richness was lower at the higher, 3200 m elevation regardless of habitat type, beetle species richness was not significantly different among sites. Plant-beetle interaction networks were strongly modular and specialized. The structure of networks showed greater differences between elevations than between habitats. The turnover of networks was determined by species composition showing a weak influence by interaction rewiring. Conclusion: Our study showed a high diversity of beetles in flowers at higher elevations within this mountain complex. The role of beetles in plant–insect interactions within some sections of temperate, montane sites appear to be underestimated and warrant further study. [ABSTRACT FROM AUTHOR]

Rhagophthalmus fugongensis Li & Liang and Rhagophthalmus lufengensis Li & Ohba are introduced as new to science. The first record of R. tonkineus in China is provided. The male genitalia of R. gibbosulus and R. giganteus are described and illustrated. The female and larva of R. giganteus and the female of R. semisulcatus are illustrated. The distribution of Rhagophthalmus is discussed and a rectification of the relative arrangement of different parts of the male genitalia is provided (the base-piece is on the ventral side of the male genitalia, and the parameres on the dorsal side). [ABSTRACT FROM AUTHOR]

Abstract: Crofton weed (Ageratina adenophora) is a highly invasive weed that has spread into several provinces of southern China. This study compares carabid assemblages originating from native pastures with assemblages in Crofton weed dominated communities in the Lancang County, Yunnan Province, to assess how the invasion of this neophyte impacts the community structure of ground-dwelling arthropods. Over a period of 16 months, a total of 1574 carabid beetles representing 28 species were collected at two types of pasture, and 679 carabid beetles representing 34 species at stands of Crofton weed. The most common carabid species, Tetragonoderus arcuatus and Harpalus indicus, were mostly found in the pastures, while four of the five rarest species were present exclusively under Crofton weed. Alpha-diversity and evenness of carabid assemblages were greater under Crofton weed. Three distinct groups of carabid species were separated according to indicator values and a characterization of habitats: habitat generalists, Crofton weed specialists and native pasture specialists. The distribution of carabid species was related to environmental parameters such as depth of litter layer, total phosphorus, height of vegetation, amount of fresh biomass and pH of the soil. According to this study, the invasion of Crofton weed will alter the structure of carabid communities, but will not necessarily reduce the alpha-diversity of carabid assemblages. [Copyright &y& Elsevier]

Cylindera (Cylindera) davidi davidi (Fairmaire, 1886), Lophyra fuliginosa (Dejean, 1826), and Myriochila sinica (Fleutiaux, 1889) are reported as range extensions to Yunnan Province. Callytron andersonii (Gestro, 1889), Calochroa elegantula (Dokhtouroff, 1882) and Neocollyris (Leptocollyris) tumida Naviaux, 1991 are reported as new records for the province and for China. Because of name and taxonomic changes to genera of tiger beetles in recent years and the addition of new genera to the record, a key is provided for separating Yunnan tiger beetles into the most recent classification of genera. The key is specific to the province and may not be appropriate for other provinces in China. Following the key is a summary list of the known species of Yunnan tiger beetles. [ABSTRACT FROM AUTHOR]

This is a study on the leaf beetle subgenus Cryptocephalus Geoffroy, 1762 from China, with the particular emphasis upon the species-group classification of the subgenus and the taxonomy of the Cryptocephalus heraldicus species group. A new key is compiled to all the species groups found in China. Four new species are described from China: Cryptocephalus (Cryptocephalus) biordopunctatus sp. nov. from Yunnan, C. hani sp. nov. from Shanxi, Hubei, Shaanxi and Gansu, C. incisodentatus sp. nov. from Sichuan and Yunnan, and C. nigroflavusiventerus sp. nov. from Yunnan. Three species are found for the first time in China: C. lacosus Pic, 1922, C. nigriceps Allard, 1891 and C. rajah Jacoby, 1908. The species C. nigrolimbatus Jacoby, 1890 is transferred from the subgenus Burlinius Lopatin to this subgenus and assigned to the Cryptocephalus heraldicus group. The species number of this group is now 30 in total according to our result of taxonomic review. A key to all the mainland China species of this species group is provided as well as high quality color images and line drawings of adult habitus, aedeagus, and other important structures. All the types of the new species are deposited in the collection of Institute of Zoology, Chinese Academy of Sciences (IZ-CAS). [ABSTRACT FROM AUTHOR]

Simple Summary: The Cerambycidae comprise a diverse (>35,000 species) family of wood-boring beetles. Many are of concern as invasive species because their long-lived larvae are readily transported around the world concealed in wooden products and packing materials. Over the past two decades, our understanding of cerambycid pheromone chemistry has advanced rapidly, with pheromone structures now described for several hundred species. Furthermore, mixtures of cerambycid pheromones have been shown to potentially act as effective multispecies lures. In this study, traps baited with generic lures deployed at ground level and in the tree canopy in 22 randomly located permanent plots in a nature reserve in Yunnan, China, captured 4541 beetles of 71 species. Using Hierarchical Modeling of Species Communities, we developed informative models for 18 species and demonstrated that trap height, slope, elevation, and leaf-area index were important determinants of cerambycid beetle distribution. Our results demonstrate the potential for using generic lures to detect and monitor cerambycid populations at ports of entry, and for the study of cerambycid beetle ecology. The Cerambycidae comprise a large and ecologically important family of wood-boring beetles. The purpose of this study was to examine the effectiveness of a generic lure as a potential monitoring tool. Working in a subtropical forest in southwest China, we set traps baited with generic lures at ground level (1 m) and canopy height (~18 m) across 22 randomly located forest plots (12 regenerating forest, 10 mature forest). Three stations were established per plot and each plot was trapped for 7 days in May–June 2013. In total, 4541 beetles of 71 species were caught, including 26 species with 10 or more individuals. We used Hierarchical Modeling of Species Communities (HMSC) to analyze the data and produced informative models for 18 species, showing that trap height, slope, elevation, and leaf-area index were important determinants of cerambycid distribution. Our results demonstrate the potential for using generic lures to detect and monitor cerambycid populations, both for regulatory purposes and for the study of cerambycid beetle ecology. Further research should focus on refining lure blends, and on repeated sampling to determine temporal and spatial dynamics of cerambycid communities. [ABSTRACT FROM AUTHOR]

In recent years, the outbreak of the pine shoot beetle (PSB), Tomicus spp., has caused serious shoots damage and the death of millions of trees in Yunnan pine forests in southwestern China. It is urgent to develop a convincing approach to accurately assess the shoot damage ratio (SDR) for monitoring the PSB insects at an early stage. Unmanned airborne vehicles (UAV)-based sensors, including hyperspectral imaging (HI) and lidar, have very high spatial and spectral resolutions, which are very useful to detect forest health. However, very few studies have utilized HI and lidar data to estimate SDRs and compare the predictive power for mapping PSB damage at the individual tree level. Additionally, the data fusion of HI and lidar may improve the detection accuracy, but it has not been well studied. In this study, UAV-based HI and lidar data were fused to detect PSB. We systematically evaluated the potential of a hyperspectral approach (only-HI data), a lidar approach (only-lidar data), and a combined approach (HI plus lidar data) to characterize PSB damage of individual trees using the Random Forest (RF) algorithm, separately. The most innovative point is the proposed new method to extract the three dimensional (3D) shadow distribution of each tree crown based on a lidar point cloud and the 3D radiative transfer model RAPID. The results show that: (1) for the accuracy of estimating the SDR of individual trees, the lidar approach (R2 = 0.69, RMSE = 12.28%) performed better than hyperspectral approach (R2 = 0.67, RMSE = 15.87%), and in addition, it was useful to detect dead trees with an accuracy of 70%; (2) the combined approach has the highest accuracy (R2 = 0.83, RMSE = 9.93%) for mapping PSB damage degrees; and (3) when combining HI and lidar data to predict SDRs, two variables have the most contributions, which are the leaf chlorophyll content (Cab) derived from hyperspectral data and the return intensity of the top of shaded crown (Int_Shd_top) from lidar metrics. This study confirms the high possibility to accurately predict SDRs at individual tree level if combining HI and lidar data. The 3D radiative transfer model can determine the 3D crown shadows from lidar, which is a key information to combine HI and lidar. Therefore, our study provided a guidance to combine the advantages of hyperspectral and lidar data to accurately measure the health of individual trees, enabling us to prioritize areas for forest health promotion. This method may also be used for other 3D land surfaces, like urban areas. [ABSTRACT FROM AUTHOR]

Yunnan pine shoot beetles (PSB), Tomicus yunnanensis and Tomicus minor have spread through southwestern China in the last five years, leading to millions of hectares of forest being damaged. Thus, there is an urgent need to develop an effective approach for accurate early warning and damage assessment of PSB outbreaks. Remote sensing is one of the most efficient methods for this purpose. Despite many studies existing on the mountain pine beetle (MPB), very little work has been undertaken on assessing PSB stress using remote sensing. The objective of this paper was to develop a spectral linear mixing model aided by radiative transfer (RT) and a new Yellow Index (YI) to simulate the reflectance of heterogeneous canopies containing damaged needles and quantitatively inverse their PSB stress. The YI, the fraction of dead needles, is a physically-explicit stress indicator that represents the plot shoots damage ratio (plot SDR). The major steps of this methods include: (1) LIBERTY2 was developed to simulate the reflectance of damaged needles using YI to linearly mix the green needle spectra with the dead needle spectra; (2) LIBERTY2 was coupled with the INFORM model to scale the needle spectra to the canopy scale; and (3) a look-up table (LUT) was created against Sentinel 2 (S2) imagery and inversed leaf chlorophyll content (LCC), green leaf area index (LAI) and plot SDR. The results show that (1) LIBERTY2 effectively simulated the reflectance spectral values on infested needles (mean relative error (MRE) = 1.4–18%), and the YI can indicate the degrees of needles damage; (2) the coupled LIBERTY2-INFORM model is suitable to estimate LAI (R2 = 0.73, RMSE = 0.17 m m−2, NRMSE = 11.41% and the index of agreement (IOA) = 0.92) and LCC (R2 = 0.49, RMSE = 56.24 mg m−2, NRMSE = 25.22% and IOA = 0.72), and is better than the original LIBERTY model (LAI: R2 = 0.38, RMSE = 0.43 m m−2, NRMSE = 28.85% and IOA = 0.68; LCC: R2 = 0.34, RMSE = 76.44 mg m−2, NRMSE = 34.23% and IOA = 0.57); and (3) the inversed YI is positively correlated with the measured plot SDR (R2 = 0.40, RMSE = 0.15). We conclude that the LIBERTY2 model improved the reflectance simulation accuracy of both the needles and canopies, making it suitable for assessing PSB stress. The YI has the potential to assess PSB damage. [ABSTRACT FROM AUTHOR]