Combining WV-2 images and tree physiological factors to detect damage stages of Populus gansuensis by Asian longhorned beetle (Anoplophora glabripennis) at the tree level

Background:Anoplophora glabripennis(Motschulsky),commonly known as Asian longhorned beetle(ALB),is a wood-boring insect that can cause lethal infestation to multiple borer leaf trees.In Gansu Province,northwest China,ALB has caused a large number of deaths of a local tree species Populus gansuensis.The damaged area belongs to Gobi desert where every single tree is artificially planted and is extremely difficult to cultivate.Therefore,the monitoring of the ALB infestation at the individual tree level in the landscape is necessary.Moreover,the determination of an abnormal phenotype that can be obtained directly from remote-sensing images to predict the damage degree can greatly reduce the cost of field investigation and management.Methods:Multispectral WorldView-2(WV-2)images and 5 tree physiological factors were collected as experimental materials.One-way ANOVA of the tree’s physiological factors helped in determining the phenotype to predict damage degrees.The original bands of WV-2 and derived vegetation indices were used as reference data to construct the dataset of a prediction model.Variance inflation factor and stepwise regression analyses were used to eliminate collinearity and redundancy.Finally,three machine learning algorithms,i.e.,Random Forest(RF),Support Vector Machine(SVM),Classification And Regression Tree(CART),were applied and compared to find the best classifier for predicting the damage stage of individual P.gansuensis.Results:The confusion matrix of RF achieved the highest overall classification accuracy(86.2%)and the highest Kappa index value(0.804),indicating the potential of using WV-2 imaging to accurately detect damage stages of individual trees.In addition,the canopy color was found to be positively correlated with P.gansuensis’damage stages.Conclusions:A novel method was developed by combining WV-2 and tree physiological index for semi-automatic classification of three damage stages of P.gansuensis infested with ALB.The canopy color was determined as an abnormal phenotype that could be directly assessed using remote-sensing images at the tree level to predict the damage degree.These tools are highly applicable for driving quick and effective measures to reduce damage to pure poplar forests in Gansu Province,China.

Cellulase in Anoplophora glabripennis adults emerging from different host tree species

In order to investigate different kinds of cellulase in insect pests, we selected male and female adults of Anoplophora glabripennis （Motschulsky） emerging from four different host species （Populus alba var. pyramidalis, P. nigra var. thevestina （Dode） Bean., P. simonii × P. pyramidliscr cv. Opera 8277 Hsu. and Salix matsudana f. lobato-glandulosa） as our research material. The enzyme activitives of three kinds of cellulase in the intestines of the adult insects were measured. The Cx-cellulase isozymes were detected with a CMC-incorporated polyacrylamide gel. The results show that： there are no statistically significant differences between the enzyme activities of males and females emerging from the different host species. The order of magnitude in activity is： Cx-cellulase 〉 β-glycosidase 〉 C1-cellulase. When the adults emerge from the same host species, there are no statistically significant differences between male and female enzyme activities of β-glycosidase and C1-cellulase, but the enzyme activity of Cx-cellulase of males is clearly higher than that of females. The patterns and migration of Cx-cellulase isozymes of males and females emerging from differ-ent hosts trees are clearly not different, and neither are they different when emerging from the same hosts.

Cellulase in Anoplophora glabripennis adults fed on original host tree species and non-original host trees

Cellulase activities of Anoplophora glabripennis （Motsch.） adults from two host plants （Populus simonii x p pyramidliscr cv. Opera Hsu. and Salix matsudana Koidz） fed on three different host tree species （Acer negundo Linn., S. matsudana Koidz and P simonii x P pyramidliscr cv. Opera Hsu.） were investigated. Enzyme activities of endoglucanase and β-glucosidase in the intestines of the insects were measured. The results show that there are no statistically significant differences in the enzyme activities of endoglucanase between male and female insects from the two host plants fed on three host trees, neither inβ-glucosidase. No statistically significant differences in the enzyme activities of endoglucanase and β-glucosidase were found between males and females from the two plants fed on three host tree species, except that the endoglucanase activity in males from the opera poplar fed on Hankow willow is lower than that fed on ash-leaf maple and opera poplar.

Oviposition Site Selection of Anoplophora glabripennis in Sugar Maple (Acer saccharum) and Its Gnawing Nidus Oviposition Habits

[Objective] The paper was to explore the oviposition site selection of Anoplophora glabripennis in sugar maple and its gnawing nidus oviposition habits. [Method] Through field and indoor rearing observation, the oviposition site selection of A. glabripennis in sugar maple was studied, and the gnawing nidus oviposition habits were analyzed. [Result] The height of oviposition site of A. glabripennis in sugar maple, the number observation holes （gnawing nidus oviposition points） and bark thickness in oviposition site showed linear correlation with diameter of branch at breast height. The gnawing nidus oviposition habit of A. glabripennis in sugar maple was mainly divided into 4 stages： gnawing nidus site selection, gnawing nidus, oviposition and nidus sealing, the duration from gnawing nidus to nidus sealing was（38.29±16.47）min. [Conclusion] The study provided reference for comprehensive prevention of A. glabripennis in greening tree species sugar maple, as well as further study on reproductive behavior and regulation mechanism of A. glabripennis.

Is there hybridization between 2 species of the same genus in sympatry?——The genetic relationships between Anoplophora glabripennis,Anoplophora chinensis,and putative hybrids

Anoplophora glabripennis(Asian longhorn beetle,ALB)and Anoplophora chinensis(Citrus longhorn beetle,CLB)are native forest pests in China;they have become important international quarantine pests.They are found using the same Salix aureopendula host tree of Cixi,Zhejiang province,China.On this host tree,we collected additional beetles that appeared to be morphologically intermediate between ALB and CLB.By using a stereoscope,we observed that there were several bumps on the base of the elytra,which was inconsistent with ALB,which typically has a smooth elytral base,but was more like CLB,which has numerous short tubercles on the elytral base.Given their sympatry and intermediate morphology,we hypothesized that these may represent ALB×CLB hybrids.We studied the genomic profiles for 46 samples(ALB,CLB,and putative hybrids)using genotyping-by-sequencing(GBS)providing a reduced representation of the entire genome.Employing principal component analyses on the 163 GBS-derived single nucleotide polymorphism data,we found putative hybrids tightly clustered with ALB,but genetically distinct from the CLB individuals.Therefore,our initial hybrid hypothesis was not supported by genomic data.Further,while mating experiments between adult ALB and CLB were successful in 4 separate years(2017,2018,2020,and 2021),and oviposition behavior was observed,no progeny was produced.Having employed population genomic analysis and biological hybridization experiments,we conclude that the putative hybrids represent newly discovered morphological variants within ALB.Our approach further confirmed the advantage of genome-wide information for Anoplophora species assignment in certain ambiguous classification cases.

Current and future control of the wood-boring pest Anoplophora glabripennis

The Asian longhorn beetle (ALB) Anoplophora glabripennis is one of the most successful and most feared invasive insect species worldwide. This review covers recent research concerning the distribution of and damage caused by ALB, as well as major efforts to control and manage ALB in China. The distribution and destruction range of ALB have continued to expand over the past decade worldwide, and the number of interceptions has remained high. Detection and monitoring methods for the early discovery of ALB have diversified, with advances in semiochemical research and using satellite remote sensing in China. Ecological control of ALB in China involves planting mixtures of preferred and resistant tree species, and this practice can prevent outbreaks. In addition, strategies for chemical and biological control of ALB have achieved promising results during the last decade in China, especially the development of insecticides targeting different stages of ALB, and applying Dastarcus helophoroides and Dendrocopos major as biocontrol agents. Finally, we analyze recommendations for ALB prevention and management strategies based on native range and invasive area research. This information will hopefully help some invaded areas where the target is containment of ALB.

Evidence for a female-produced, long range pheromone of Anoplophora glabripennis （Coleoptera Cerambycidae）

Volatiles from female Asian longhorned beetle （ ALB ）, Anoplophora glabripenhis, were evaluated as candidate sex pheromone components. Previous studies on ALB have revealed several antennally active compounds from virgin females; however the origins and activity of these compounds were not apparent and require further investigation. We tested the hypothesis that one or more of the ALB contact sex pheromones is a precursor that undergoes abiotic oxidation to yield volatile pheromone components, and evaluated the activity of these compounds using laboratory and field bioassays. Gas chromatogra- phy coupled electroantennography detection （GC-EAD） analysis indicated the presence of three antennally active aldehydes （heptanal, nonanal, and hexadecanal） in female cuticular extracts exposed to ozone or UV and visible light. In laboratory bioassays using a Y-tube olfactometer, males were preferentially attracted to ozonized female body washes over crude body washes. Similarly, synthetic formulations of these compounds were preferred over controls in the olfactometer. Field trapping experiments conducted from 2006 to 2008 in Ningxia, China showed that synthetic lures of the three aldehydes formulated in a ratio simulating that of virgin females attracted more beetles compared to controls, and that combinations of these aldehydes, linalool oxide, and host kairomones captured more beetles than controls, and captured significantly more males.

Selectivity mechanism of Anoplophora glabripennis on four different species of maples

Anoplophora glabripennis(Motsch.)is a wood-boring beetle that is native to China.For a long time,it caused great losses in the economy and ecology of northwest China.Attractants are often used to control insects.The volatiles emitted from the host plant play an important role for insects in finding their target.To explore the mechanism of selec-tivity to different host plants,the response of Anoplophora glabripennis to four different host plants was investigated,which included Acer negundo L.,Acer mono Maxim.,Acer truncatum Bunge.and Acer platanoides L.,and the com-pounds in the profiles of volatiles were identified from these species.The olfactory responses of Anoplophora glabripennis to the odors of different plants showed preference for certain host plants:Acer negundo,Acer mono and Acer truncatum.The attraction of Acer negundo and Acer mono was signifi-cantly different(p<0.05).The attraction of Acer negundo to the insects was stronger than to Acer mono.Acer platanoides neither attracted nor repelled the insects.Compounds in the profiles of volatiles from the above four species were identified and quantified by gas chromatography-mass spec-trometry(GC-MS)equipped with a CP-4020 termodesorp-tion and cold trap(TCT)device.The constituents of volatiles and the relative concentrations were different in the four host species.The amount of ketones,alcohols and aldehydes in the four plants showed the same order:Acer negundo<Acer mono<Acer truncatum<Acer platanoides,while that of alkanes and esters was quiet different:Acer negundo L.>Acer mono Maxim.>Acer truncatum Bunge.>Acer platanoides L..1-penten-3-ol,ocimene and trans-Germanylacetone were repellent to Anoplophora glabripennis.1-penten-3-ol and trans-gerranylacetone were identified in Acer platanoides,and Ocimene was the most attractive to Anoplophora glabripennis among these species.The extent of feeding damage caused by Anoplophora glabripennis differed among four species.The sequences was Acer negundo>Acer mono>Acer truncatum>Acer platanoides.The epidermal hairs of the four host plants revealed that the extent of damage was related to the physical characteristics of the host plants.

Electrophysiological and Behavioral Responses of Adult Anoplophom glabripennis (Motschulsky) to Volatile Components of Host-Plant

Electrophysiological and behavioral responses of adult A. glabripennis (Motsch.) to volatiles from ashleaf maple (Acer negundo L.) were investigated to identify semiochemicals involved in host location. Measurable electroantennogram (BAG) responses were elicited to all compounds tested, the most effective antennal stimulants were trans-2-hexen-1-al,decyl aldehyde and trans-2-hexenl-ol.These profiles were similar between males and females. In Y-tube olfactometer bioassays, above three compounds with certain concentration, trans-2-hexen-l-al (1%), trans-2-hexen-l-ol (1%) and decyl aldehyde (10%), were significantly attractive to the adults in laboratory. The results show that either BAG or olfactory responding to a particular volatile compound are markedly influenced by the concentration.

Identification and Characterization of Peptides Binding AgEG1 from a Phage Display Library

Endoglucanases are the main cellulolytic enzymes digestion as well as its good kinetic properties make it an attractive of Anoplophora glabripennis. Their high activities in cellulose target for development of cellulase inhibitors. In this study, random pepfide phage display technology was employed to identify peptides that bound the AgEG1, a member of endoglucanase isozymes. Phage clones with peptide LPPNPTK and XPP （X is residue T, L, A or H） motif frequently occurred in the selected phage population and showed a higher phage recovery than other clones. Peptide LPPNPTK was chemically synthesized and characterized tor its binding activities to AgEG1. The synthetic peptide exhibited high specificity for AgEG1. The peptide LPPNPTK has the potential to be developed into inhibitors of the endoglucanase of A. glabripennis.