Monochamus Alternatus Hope Research Articles

Morphological and optical features of the apposition compound eye of Monochamus alternatus Hope (Coleoptera: Cerambycidae)

The Japanese pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is currently the most destructive forest pest as it transmits the pine wilt nematode Bursaphelenchus xylophilus. Morphological, optical features and dark/light adaptational changes of the compound eyes of M. alternatus adults were examined by light, scanning and transmission electron microscopy. The eye of M. alternatus is apposition type and contains 489–712 ommatidia, depending on the beetle’s body size. Each ommatidium features a large corneal lens, composed of a thick inner lens (ILU) and a thin outer lens unit (OLU); an acone-type of cone of four cone cells, a semi-fused type of rhabdom formed by eight retinular cells (two central cells: R7-R8 surrounded by six peripheral cells: R1-R6). Dark/light adaptational changes affect size and shape of the cones as well as the rhabdom’s cross-sectional area and outline, to optimize the amount of light that reaches the photopigment. The compound eyes of M. alternatus have an F-number of 0.94, an interommatidial angle of 5.34°, an eye parameter P of 4.98 μm rad and a ratio of acceptance to interommatidial angle of 0.45. The eye is characterized by relatively poor spatial resolution, but can be expected to exhibit high absolute sensitivity and contrast in dim light.

Time-course transcriptomic study of phenolic metabolism and P450 enzymes in Pinus massoniana Lamb. after feeding by Monochamus alternatus Hope

ABSTRACTPinus massoniana Lamb. is an economically important pioneer conifer in southern China. Monochamus alternatus is considered the vector insect of the Bursaphelenchus xylophilus, a nematode that can cause destructive pine wilt disease. Many phenolic compounds have been identified to play key roles in plant defense against biotic/abiotic damages in multiple ecosystems. In addition, the cytochrome p450 enzymes reportedly participate in various secondary metabolism pathways in plant. Surprisingly, however, no study has characterized putative phenolic defenses nor the P450 enzymes in P. massoniana inoculated by M. alternatus at the transcriptome level. Here, we compared changes in the whole transcriptome by RNA-Seq, finding that different expressed genes in phenolic biosynthetic related pathways were significantly enriched, indicating phenolic secondary metabolism in P. massoniana was activated after M. alternatus feeding. Using qRT-PCR, we then explored the changes of limiting enzyme genes in phenolic biosynthetic pathways during a series sampling time-point in both M. alternatus feeding treatment and control. Expression profile of target genes varied in their expression level, initial reaction time, peak time and reaction duration. This study provides a platform for better understanding molecular changes that could aid forest protection and breeding efforts to improve performance in the face of biotic damage.

Transmission of Bursaphelenchus xylophilus between Monochamus alternatus and Monochamus saltuarius through interspecific mating behaviour

AbstractCerambycid adults of the genus Monochamus transmit the pine wood nematode (Bursaphelenchus xylophilus [Steiner et Buhrer] Nickle), the causative agent of pine wilt disease. To confirm the transmission of B. xylophilus between vector species, nematode‐infected Monochamus alternatus Hope and nematode‐free Monochamus saltuarius (Gebler) adults were paired and their behaviour was observed for 107–220 min. In three pairs that exhibited mounting without copulation, nematode transmission occurred, whereas it was not found in another pair without mountings. The effect of nematode transmission between different vector species on the invasion biology of B. xylophilus is discussed.

Modelling the Incursion and Spread of a Forestry Pest: Case Study of Monochamus alternatus Hope (Coleoptera: Cerambycidae) in Victoria

Effective and efficient systems for surveillance, eradication, containment and management of biosecurity threats require methods to predict the establishment, population growth and spread of organisms that pose a potential biosecurity risk. To support Victorian forest biosecurity operations, Agriculture Victoria has developed a landscape-scale, spatially explicit, spatio-temporal population growth and dispersal model of a generic pest pine beetle. The model can be used to simulate the incursion of a forestry pest from a nominated location(s), such as an importation business site (approved arrangement, AA), into the surrounding environment. The model provides both illustrative and quantitative data on population dynamics and spread of a forestry pest species. Flexibility built into the model design enables a range of spatial extents to be modelled, from user-defined study areas to the Victoria-wide area. The spatial resolution of the model (size of grid cells) can be altered from 100 m to greater than 1 km. The model allows core parameters to be altered by the user, enabling the spread of a variety of windborne insect species and pathogens to be investigated. We verified the model and its parameters by simulating and comparing the outputs with the 1999/2000 Melbourne incursion, but no establishment of a forestry pest beetle was believed to be Monochamus alternatus Hope (Coleoptera: Cerambycidae). The model accurately predicts the distance and direction of the historic incursion, and the subsequent failure to establish is due to low overall population density of the pest species.

The bimodal adult activity of Monochamus alternatus (Coleoptera: Cerambycidae) caught in pheromone traps in Jeju can be explained by the competitive attractiveness of dying pine trees

AbstractThe Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), is known to be the primary vector of pinewood nematode Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle that causes pine wilt disease. Adult activity of M. alternatus caught in a pheromone trap on Jeju Island of Korea showed a bimodal form with the first peak in mid to late June and the second peak in mid to late September. The two peaks were separated between mid and late August, showing a valley. Accumulated degree‐days predicted that the emergence of the second generation adults could be possible just before the second peak. But actually no adults of the second generation occurred in the field development experiments of M. alternatus in 2016 and 2017. Pine trees without oleoresin flow (namely dying trees by the infection of pinewood nematode) were abundant during early July to early August. The bimodal adult activity pattern of M. alternatus could be partially explained by the competitive attractiveness of dying trees against pheromone traps, when we accepted the assumption that dying pine trees attract strongly M. alternatus.

The Developmental Characteristics for the Head Capsule Width ofMonochamus alternatus(Coleoptera: Cerambycidae) Larvae and Determination of the Number of Instars

The objective of this study was to determine the number of instars of Monochamus alternatus Hope (Coleoptera: Cerambycidae) larvae by comparing their head capsule widths (HCW) published in previous studies, as well as additional laboratory experiments. Larvae of M. alternatus showed repeated molting in the laboratory. Most larvae ceased their development at the 10th instar stage. Frequency distributions of HCW for the first, second, and third instar larvae were clearly separated while those of the fourth through 11th instar larvae largely overlapped between successive instars in our results. The HCW values for the first, second, and third instar larvae directly measured for each instar in our study indicated that they were more precise than those of previous reports based on field-collected HCW which might have missed HCW of the first instar larvae or wrongly determined HCW for some instars. Unlike the reports of four instars of previous studies, M. alternatus larvae passed five instars in the field, which was confirmed by the discovery of five pairs of mandibles in the feeding gallery and pupal chamber. Also, the comparative study for the frequency distributions of HCW revealed that most M. alternatus larvae passed five instars. Consequently, the average sizes of HCW for their first, second, and third instar larvae are newly suggested to be 0.896 ± 0.069, 1.291 ± 0.131, and 1.707 ± 0.165 mm (mean ± SD) .

<p class="Body">First record of the genus Paracarophenax (Acari: Acarophenacidae) from China, with description of a new species

A new species Paracarophenax alternatus Xu and Zhang sp. nov. is described and illustrated based on phoretic females. The mites were found attached to the adult of Monochamus alternatus Hope (Coleoptera: Cerambycidae) collected from traps set in Minhou county, Fuzhou city, Fujian province, China. The new species is the eighth representative of the genus and also the first record of the Paracarophenax associated with the host family Cerambycidae. An updated the key to species of Paracarophenax is provided.

Analysis of Potential Molecular Targets inMonochamus alternatus(Coleoptera: Cerambycidae) Inoculated withBeauveria bassiana(Deuteromycotina: Hyphomycetes)

Abstract Monochamus alternatus Hope, the Japanese pine sawyer (Coleoptera: Cerambycidae), is a longhorn beetle that is a known vector of the pinewood nematode Bursaphelenchus xylophilus (Steiner et Buhrer) Nickel. Beauveria bassiana (Balsamo) Vuillemin is an entomopathogenic fungus that is widely used as a microbial control agent because of its ease of mass production and safety to most vertebrates. To identify molecular targets that are potentially associated with B. bassiana toxicology, differentially expressed gene (DEG) libraries of M. alternatus contacted with B. bassiana have been prepared. The transcripts are sequenced using the Ion Proton platform; We identify 5,637, 9,181, and 1,787 sequences that involved cellular components, molecular functions, and biological processes, respectively. Fifty DEGs are enriched in the metabolism of xenobiotics by the cytochrome P450 pathway, and 33 DEGs are enriched in insect hormone biosynthesis by a Kyoto Encyclopedia of Genes and Genomes pathway enrichment ana...

Identification of differentially expressed immunity‐related genes in Monochamus alternatus Hope (Coleoptera: Cerambycidae) larvae parasitized by Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae)

AbstractThe pine sawyer Monochamus alternatus Hope (Coleoptera: Cerambycidae) is a serious pest of several Pinus species, and the ectoparasitoid larvae of Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important natural enemy of this pest. The transcriptome of M. alternatus larvae was sequenced using the Illumina platform and immunity‐related genes were specifically analyzed. De novo assembly resulted in the identification of 24 241 unigenes, with a mean length of 1122 bp, in unparasitized M. alternatus larvae and 23 807 unigenes, with a mean length of 1140 bp, for parasitized larvae. Removal of redundant unigenes resulted in 26 095 all‐unigenes, of which 16 959 (64.99%) showed clear homology with some of the known genes in the National Center for Biotechnology Information nr database. Parasitization had notable effects on the transcriptome profile of M. alternatus larvae. In all, 2702 genes were differentially expressed in M. alternatus larvae after parasitization, with 1491 (55.18%) upregulated and 1211 (44.82%) downregulated. Moreover, expression levels of immunity‐related genes in M. alternatus larvae were markedly altered in response to parasitization by D. helophoroides. In conclusion, the transcriptome profiling data, especially the discovered of immunity‐related genes, help illustrate the molecular mechanisms of parasitism between D. helophoroides and M. alternatus and provide new insights into developing immunity regulation‐mediated control methods of M. alternatus.

Identification of Aggregation-Sex Pheromone of the Korean Monochamus alternatus (Coleoptera: Cerambycidae) Population, the Main Vector of Pine Wood Nematode.

We confirmed an aggregation-sex pheromone of the Korean Monochamus alternatus Hope (Coleoptera: Cerambycidae) population, which primarily transmitted the pine wood nematode in Korea. Only the M. alternatus male emitted monochamol which has been previously reported in the Chinese M. alternatus population. In field attraction testing, the monochamol+α-pinene+ethanol combination attracted more M. alternatus adult beetles than traps containing only monochamol, ethanol, or α-pinene. The bark beetle aggregation pheromone compounds of ipsenol, ipsdienol, and ipsenol+ipsdienol, did not show synergistic effects with the monochamol+α-pinene+ethanol combination. No synergistic effects were observed when each host volatile compound of 3-carene, β-caryophyllene, limonene, myrcene, and β-pinene was added to traps containing monochamol+α-pinene+ethanol. The ratio of female beetles was much higher in traps containing the monochamol+α-pinene+ethanol combination than that of the natural population. Our results indicated that pheromone and synergists could be useful for managing the M. alternatus population.

Effects of low-temperature summer nights on adults of Monochamus alternatus (Coleoptera: Cerambycidae)

ABSTRACTTo clarify the factors determining the northern distribution limit of Monochamus alternatus Hope, which vectors the pinewood nematode, we examined our hypothesis that “low-temperature summer nights in cool regions affect the survival, maturation feeding, and ovary development of M. alternatus, and determine its distribution limit.” We measured summer air temperatures in three pine forest stands in northern Japan. Based on the results, we examined the effects of low nighttime temperatures on survival, maturation feeding, and ovary development in the laboratory. Low nighttime temperatures had little effect on the survival and the total amount of maturation feeding of M. alternatus adults. A daytime temperature of 25°C and nighttime temperature of 15°C did not affect ovary development. In contrast, 25°C in the daytime and 10°C in the nighttime delayed ovary development and reduced the number of mature eggs, but some ovary eggs were able to mature under this condition. We concluded that the effect of low-temperature summer nights on ovary development alone could not explain the northern distribution limit of M. alternatus.

Functional characteristics of chemosensory proteins in the sawyer beetle Monochamus alternatus Hope.

The Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae), is a major pest of pines and it is also the key vector of the exotic pinewood nematode in China. In the present study, we cloned, expressed, and purified a chemosensory protein (CSP) in M. alternatus. We surveyed its expression in various developmental stages of male and female adult tissues and determined its binding affinities for different pine volatiles using a competitive binding fluorescence assay. A CSP known as CSP5 in M. alternatus was obtained from an antennal cDNA library and expressed in Escherichia coli. Quantitative reverse transcription polymerase chain reaction results indicated that the CSP5 gene was mainly expressed in male and female antennae. Competitive binding assays were performed to test the binding affinity of recombinant CSP5 to 13 odour molecules of pine volatiles. The results showed that CSP5 showed very strong binding abilities to myrcene, (+)-β-pinene, and (-)-isolongifolene, whereas the volatiles 2-methoxy-4-vinylphenol, p-cymene, and (+)-limonene oxide have relatively weak binding affinity at pH 5.0. Three volatiles myrcene, (+)-β-pinene, and (-)-isolongifolene may play crucial roles in CSP5 binding with ligands but this needs further study for confirmation. The sensitivity of insect to host plant volatiles can effectively be used to control and monitor the population through mass trapping as part of integrated pest management programs.

Monochamus alternatus(Coleoptera: Cerambycidae) Hemolymph Saccharide Content and Carbohydrase Activity in Response to Parasitism byDastarcus helophoroides(Coleoptera: Bothrideridae)1

Abstract Monochamus alternatus Hope (Coleoptera: Cerambycidae) is the main borer of several pine species (e.g. Pinus massoniana Lamb) and is also the primary vector of the pest pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle (Aphelenchida: Parasitaphelenchidae). Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is a natural enemy and an ectoparasitoid of M. alternatus. We studied the effects of parasitism by D. helophoroides on the hemolymph saccharide content in parasitized M. alternatus larvae. Our results showed that hemolymph saccharide content was altered by parasitism. For example, in comparison to unparasitized insects, the total sugar content increased in larvae 12 h after parasitism, the reducing sugar content declined at 24 h after parasitism but increased at 72 h after parasitism, and the trehalose content was inhibited at 6 h and 24 h after parasitism. These results indicate that D. helophoroides larvae may regulate saccharide metabolism in M. alternatu...

Field Evaluation of Commercial Attractants and Trap Placement for Monitoring Pine Sawyer Beetle, Monochamus alternatus (Coleoptera: Cerambycidae) in Guangdong, China.

The pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is a serious insect pest of pine trees by vectoring the pine wood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle (Nematoda: Aphelenchoididae). Field studies were carried out during 2013-2015 in Guangdong (China) to evaluate the effectiveness of commercial attractants, effect of trap placement for monitoring M. alternatus, and temporal patterns of trap catch. Four commercial attractants, three trap placements (0, 1.5, and 3 m above ground) and different trapping distances (50, 200, 400, 600, and 900 m) from forest edge were evaluated for monitoring M. alternatus. Traps baited with a mixture of monochamol and plant volatiles captured significantly more beetles than traps baited with monochamol alone or plant volatiles alone. Traps set up at 1.5 m above the ground captured significantly more M. alternatus than those at 0 m and 3 m height. Based on 2,687 beetles trapped from two locations in 2013 and 2014, the female:male ratio was 2.9-4.1:1. The beetles' natural dispersal distance was approximately 100 m based on traps set at different distances from edge of the forest. Continuous monitoring over 38-wk period indicates the peak of adult M. alternatus emergence was between May and June within a year.

Screening behaviorally active compounds based on fluorescence quenching in combination with binding mechanism analyses of SspOBP7, an odorant binding protein from Sclerodermus sp.

Reverse chemical ecology approaches based on the recognition and transport function of odorant binding proteins (OBPs) have been used to screen behaviorally active compounds of insects. In the first place, behaviorally active compounds from Sclerodermus sp., an important ectoparasite of Monochamus alternatus Hope, were screened by SspOBP7. The Fluorescence quenching assays revealed that only six of 19 ligands that had binding affinities in fluorescence competition-binding assays formed complexes with SspOBP7. Pursuing this further, two non-polar ligands, terpinolene and (+)-α-longipinene showed strong attractant activities for Sclerodermus sp. The pH change could lead to conformational transition of SspOBP7 from one state to another, which results in low binding affinities at low pH. Finally, a mutational analysis of the SspOBP7 binding cavity proved that changing the cavity had a greater effect on non-polar ligands, and the specific recognition of ligands by SspOBP7 might depend mainly on the appropriate shapes of the cavity and ligands. The most obvious finding to emerge from this work is that the use of fluorescence quenching to study the binding mechanism of OBPs could aid reverse chemical ecology approaches by narrowing the scope of candidate behaviorally active compounds.

Overexpression of Three Heat Shock Proteins Protects Monochamus alternatus (Coleoptera: Cerambycidae) From Thermal Stress

Ambient temperature is an important factor limiting the abundance and distribution of insects, and heat shock protein (Hsp) gene expression is sensitive to extremes of cold and heat. In order to explore the role of Hsps during thermal stress and development in Monochamus alternatus Hope (Coleoptera: Cerambycidae), we cloned and characterized full-length Hsp genes, including MaHsp60, MaHsp70, and MaHsp90. M. alternatus were exposed to different temperatures (−15, −5, 5, 15, 25, 35, and 40℃) for 1 h and was allowed to recover at 25℃ for 1 h. Following the treatments, we investigated the expression of the Hsps by quantitative real-time polymerase chain reaction. In third instar larvae, MaHsp60, MaHsp70, and MaHsp90 expression was upregulated in response to cold and heat, but the three Hsps were especially sensitive to heat, specifically at 35℃ and 40℃. After heating M. alternatus to 35℃, the expression of MaHsp60, MaHsp70, and MaHsp90 was higher than at 5℃ and 25℃ in nearly all developmental stages. MaHsp60, MaHsp70, and MaHsp90 expression was highest in later pupal, early adult, and early adult stages, respectively. These results suggest that compared with normal ambient temperatures, thermal stress could induce high expression of the three Hsps.

Bacterial Communities Associated With the Pine Wilt Disease Vector Monochamus alternatus (Coleoptera: Cerambycidae) During Different Larval Instars

We investigated the influence of larval instar on the structure of the gut bacterial community in the Japanese pine sawyer, Monochamus alternatus (Hope; Coleoptera: Cerambycidae). The diversity of the gut bacterial community in early, phloem-feeding larvae is significantly higher than in later, wood-feeding larvae. Many of these associates were assigned into a few taxonomic groups, of which Enterobacteriaceae was the most abundant order. The predominant bacterial genus varied during the five instars of larval development. Erwinia was the most abundant genus in the first and fifth instars, Enterobacter was predominant in the third and fourth instars, and the predominant genus in the second instars was in the Enterobacteriaceae (genus unclassified). Actinobacteria were reported in association with M. alternatus for the first time in this study. Cellulomonadaceae (Actinobacteria) was the second most abundant family in the first instar larvae (10.6%). These data contribute to our understanding of the relationships among gut bacteria and M. alternatus, and could aid the development of new pest control strategies.

Morphology and Ultrastructure of the Antennal Sensilla of Japanese Sawyer Beetle Monochamus alternatus Hope (Coleoptera: Cerambycidae)

Sensilla are sense organs in insects, generally comprising of a group of cuticle or epi-dermal cells that appear as hairs or rod-shaped structures. Sensilla serve as the functional elements of sensory systems. The morphology and ultrastructure of sensilla on the antennae of mature male and female Japanese sawyer beetles, Monochamus alternatus Hope (Coleoptera: Cerambycidae), were examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Five types of sensilla (sensilla basiconica, sensilla trichodea, sensilla digit-like, sensilla rod-like, and sensilla bottle-like) were observed on antennae of males, and four types of sensilla (sensilla basiconica, sensilla trichodea, sensilla bottle-like, and sensilla chaetica) were observed on antennae of females. Sensilla basiconica and sensilla trichodea were found to be abundant on the front elevation of the antennae. TEM micrographs of sensilla basiconica on the antennae of M. alternatus clearly showed that they had no pits in the cuticular region. Micrographs of longitudinal sections of sensilla trichodea showed them to be flat-tipped and smooth-surfaced pegs with pointed tips that are suggestive of a gustatory function. TEM micrographs of sensilla chaetica longitudinal sections showed dendrite branches and no cuticular pore; these sensilla may be involved in the perception of humidity, temperature, heat, and CO2. These results are discussed in relation to the possible roles of the sensilla types in the host-locating behavior of M. alternatus.

Genetic Population Structure of Dastarcus helophoroides (Coleoptera: Bothrideridae) From Different Long-Horned Beetle Hosts Based on Complete Sequences of Mitochondrial COI.

Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important natural enemy of long-horned beetles in China, Japan, and Korea. In this study, the genetic sequence of cytochrome oxidase subunit Ι was used to investigate the genetics and relationships within and among D. helophoroides populations collected from five different geographic locations. We used principal component analysis, heatmap, and Venn diagram results to determine the relationship between haplotypes and populations. In total, 26 haplotypes with 51 nucleotide polymorphic sites were defined, and low genetic diversity was found among the different populations. Significant genetic variations were observed mainly within populations, and no correlation was found between genetic distribution and geographical distance. Low pairwise fixation index values (-0.01424 to 0.04896) and high gene flows show that there was high gene exchange between populations. The codistributed haplotype DH01 was suggested to be the most ancestral haplotype, and other haplotypes were thought to have evolved from it through several mutations. In four of the populations, both common haplotypes (DH01, DH03, and DH22) and unique haplotypes were found. Low genetic diversity among different populations is related to a relatively high flight capacity, host movement, and human-aided dispersal of D. helophoroides. The high gene exchange and typically weak population genetic structure among five populations, especially among populations of Anoplophora glabripennis (Motschulsky), Monochamus alternatus (Hope), and Massicus raddei (Blessig), may suggest that these populations cross naturally in the field.

Expression pattern and ligand‐binding properties of odorant‐binding protein 13 from Monochamus alternatus hope

AbstractOdorant‐binding proteins (OBPs) are believed to play an important role in olfactory recognition. In this study, expression pattern and fluorescence binding characteristics of MaltOBP13 from the Japanese pine sawyer beetle, Monochamus alternatus Hope, were investigated via qPCR analysis of MaltOBP13 mRNA level and binding assay of MaltOBP13 and ligands. qPCR monitoring indicated MaltOBP13 mainly expressed in newly emerged males, particularly highly expressed in the last abdominal segment of males, and the expression level was significantly higher in 13‐day‐old mated adults than those of other stages. To further understand the function of the MaltOBP13 protein in odorant reception, the binding affinity of recombinant MaltOBP13 to ligands was tested by fluorescence binding assays with N‐phenyl‐1‐naphthylamine as a fluorescent probe. The results of this assay indicated that MaltOBP13 exhibited a high binding affinity for pine volatiles and binding capacity was higher in acidic conditions than in neutral environment, indicating a possible role in finding host plants.