Chromosome-level genome assembly of the Japanese sawyer beetle Monochamus alternatus.

The Japanese sawyer beetle Monochamus alternatus (Coleoptera: Cerambycidae) is a pest in pine forests and acts as a vector for the pine wood nematode Bursaphelenchus xylophilus, which causes the pine wilt disease. We assembled a high-quality genome of M. alternatus at the chromosomal level using Illumina, Nanopore, and Hi-C sequencing technologies. The assembled genome is 767.12 Mb, with a scaffold N50 of 82.0 Mb. All contigs were assembled into ten pseudo-chromosomes. The genome contains 63.95% repeat sequences. We identify 16, 284 protein-coding genes in the genome, of which 11,244 were functionally annotated. The high-quality genome of M. alternatus provides an invaluable resource for the biological, ecological, and genetic study of this beetle and opens new avenues for understanding the transmission of pine wood nematode by insect vectors.

Effects of fungicides on fitness and Buchnera endosymbiont density in Aphis gossypii.

BACKGROUND: Several agricultural fungicides are known to affect insect pests directly and these effects may be transgenerational and mediated through impacts on endosymbionts, providing opportunities for pest control. The cotton aphid Aphis gossypii is a polyphagous pest that can cause large crop yield losses. Here, we tested the effects of three fungicides, pyraclostrobin, trifloxystrobin and chlorothalonil, on the fitness and Buchnera endosymbiont of A. gossypii. RESULTS: The formulations of trifloxystrobin and pyraclostrobin, and the active ingredient of pyraclostrobin produced dose-dependent mortality in A. gossypii, whereas there was no dose-dependent mortality for chlorothalonil. The formulations of trifloxystrobin and pyraclostrobin significantly reduced the lifespan and fecundity of A. gossypii, and increased the density of Buchnera in the parental generation but not the (unexposed) F1 . When the active ingredient of pyraclostrobin was tested, the lifespan of the F0 generation was also reduced, but the density of Buchnera was not, indicating that non-insecticidal chemicals in the fungicide formulation may affect the density of the endosymbiont of A. gossypii. There was no transgenerational effect of the active ingredient of pyraclostrobin on the lifespan and Buchnera of (unexposed) F1 . CONCLUSIONS: Our results suggest that formulations of two strobilurin fungicides have immediate impacts on the fitness of A. gossypii, and chemicals in the formulation impact the density of the primary Buchnera endosymbiont. Our study highlights the potential effects of non-insecticidal chemicals of fungicides on aphid pests and their primary endosymbionts but direct connections between fitness and Buchnera densities remain unclear. © 2023 Society of Chemical Industry.

Host-plant adaptation in xylophagous insect-microbiome systems: Contributionsof longicorns and gut symbionts revealed by parallel metatranscriptome.

Adaptation to host plants is of great significance in the ecology of xylophagous insects. The specific adaptation to woody tissues is made possible through microbial symbionts. We investigated the potential roles of detoxification, lignocellulose degradation, and nutrient supplementation of Monochamus saltuarius and its gut symbionts in host plant adaptation using metatranscriptome. The gut microbial community structure of M. saltuarius that fed on the two plant species were found to be different. Plant compound detoxification and lignocellulose degradation genes have been identified in both beetles and gut symbionts. Most differentially expressed genes associated with host plant adaptations were up-regulated in larvae fed on the less suitable host (Pinus tabuliformis) compared to larvae fed on the suitable host (Pinus koraiensis). Our findings indicated that M. saltuarius and its gut microbes respond to plant secondary substances through systematic transcriptome responses, allowing them to adapt to unsuitable host plants.

Cradle for the newborn Monochamus saltuarius: Microbial associates to ward off entomopathogens and disarm plant defense.

The Japanese pine sawyer, Monochamus saltuarius, as a beetle vector of Bursaphelenchus xylophilus (pine wood nematode), is an economically important forest pest in Eurasia. To feed on the phloem and xylem of conifers, M. saltuarius needs to overcome various stress factors, including coping with entomopathogenic bacteria and also various plant secondary compounds (PSCs). As an important adaptation strategy to colonize host trees, M. saltuarius deposit eggs in oviposition pits to shield their progeny. These pits harbor bacterial communities that are involved in the host adaptation of M. saltuarius to the conifers. However, the composition, origin, and functions of these oviposition pit bacteria are rarely understood. In this study, we investigated the bacterial community associated with M. saltuarius oviposition pits and their ability to degrade PSCs. Results showed that the bacterial community structure of M. saltuarius oviposition pits significantly differed from that of uninfected phloem. Also, the oviposition pit bacteria were predicted to be enriched in PSC degradation pathways. The microbial community also harbored a lethal strain of Serratia, which was significantly inhibited. Meanwhile, metatranscriptome analysis indicated that genes involved in PSCs degradation were expressed complementarily among the microbial communities of oviposition pits and secretions. In vitro degradation showed that bacteria cultured from oviposition pits degraded more monoterpenes and flavonoids than bacteria cultured from uninfected phloem isolates. Disinfection of oviposition pits increased the mortality of newly hatched larvae and resulted in a significant decrease in body weight in the early stages. Overall, our results reveal that M. saltuarius construct oviposition pits that harbor a diverse microbial community, with stronger PSCs degradation abilities and a low abundance of entomopathogenic bacteria, resulting in the increased fitness of newly hatched larvae.

The genus Alcochera Frster (Hymenoptera, Ichneumonidae, Ctenopelmatinae) in China with a key to world species.

Two new species of Alcochera (Ichneumonidae, Ctenopelmatinae, Mesoleiini), Alcochera flavoclypeata Sheng Sun, sp. nov. collected from Labagoumen Natural Reserve, Huairou, Beijing, and A. truncata Sheng Sun, sp. nov. from Wugongshan Natural Reserve, are described and illustrated. An updated taxonomic key to world species of Alcochera is provided.

Gut Bacteria Associated With Monochamus saltuarius (Coleoptera: Cerambycidae) and Their Possible Roles in Host Plant Adaptations.

Monochamus saltuarius (Coleoptera: Cerambycidae) is an important native pest in the pine forests of northeast China and a dispersing vector of an invasive species Bursaphelenchus xylophilus. To investigate the bacterial gut diversity of M. saltuarius larvae in different host species, and infer the role of symbiotic bacteria in host adaptation, we used 16S rRNA gene Illumina sequencing and liquid chromatography-mass spectrometry metabolomics processing to obtain and compare the composition of the bacterial community and metabolites in the midguts of larvae feeding on three host tree species: Pinus koraiensis, Pinus sylvestris var. mongolica, and Pinus tabuliformis. Metabolomics in xylem samples from the three aforementioned hosts were also performed. Proteobacteria and Firmicutes were the predominant bacterial phyla in the larval gut. At the genus level, Klebsiella, unclassified_f__Enterobacteriaceae, Lactococcus, and Burkholderia-Caballeronia-Paraburkholderia were most dominant in P. koraiensis and P. sylvestris var. mongolica feeders, while Burkholderia-Caballeronia-Paraburkholderia, Dyella, Pseudoxanthomonas, and Mycobacterium were most dominant in P. tabuliformis feeders. Bacterial communities were similar in diversity in P. koraiensis and P. sylvestris var. mongolica feeders, while communities were highly diverse in P. tabuliformis feeders. Compared with the other two tree species, P. tabuliformis xylems had more diverse and abundant secondary metabolites, while larvae feeding on these trees had a stronger metabolic capacity for secondary metabolites than the other two host feeders. Correlation analysis of the association of microorganisms with metabolic features showed that dominant bacterial genera in P. tabuliformis feeders were more negatively correlated with plant secondary metabolites than those of other host tree feeders.

A new species and new records of the genus Alexeter Förster (Hymenoptera, Ichneumonidae, Ctenopelmatinae) from Beijing with a key to Chinese species.

A new species, Alexeterbeijingensis Sheng, sp. nov., and two new records for China, A.angularis (Uchida, 1952) and A.shakojiensis Uchida, 1930, collected in Mentougou, Beijing, belonging to the tribe Mesoleiini of the subfamily Ctenopelmatinae (Hymenoptera, Ichneumonidae), are reported. A key to the six species of Alexeter known from China is given.

Invasive atypical thymic carcinoid: three case reports and literature review.

Atypical thymic carcinoid is an extremely rare thymic neuroendocrine tumor derived from the neuroendocrine system. The aims of this paper were to investigate the clinical features of atypical thymic carcinoid and collate information and experience to improve the diagnosis and treatment of this disease. We describe three cases of atypical carcinoid of the thymus; clinical features, pathological data, treatment modalities, and short-term patient outcomes were summarized and analyzed. The initial clinical symptoms and signs of all three patients were nonspecific and an anterior mediastinal mass was found in each patient on chest computed tomography scan. All three patients underwent surgical resection (total thymectomy and complete excision of the tumor), followed by postoperative radiotherapy, with or without chemotherapy. The diagnoses of three patients were confirmed by pathological and immunohistochemical evaluation. We also present a review of the literature to collate as much information as possible and provide a reference for proper diagnosis and treatment of atypical thyroid carcinoid.

Antennal sensilla and ovipositor morphology of the European birch sawfly Arge pullata Zadd (Hymenoptera: Tenthredinidae, Argidae).

Arge pullata Zadd is an important phytophagous pest that damages red birch Betula albo-sinensis in Hubei Province, South China. Massive ecological and economic losses have been caused by this species, which threatens the ecological security of the Shennongjia Nature Reserve. To investigate the mechanoreception, chemoreception, and oviposition processes of A. pullata, scanning electron microscopy and optical confocal microscopy were used to reveal the typology, morphology, and distribution of ovipositor and antennal sensilla. The results show that A. pullata has clavate antennae and eight types of sensilla in total, including sensilla chaetica, sensilla trichodea (types 1-3), sensilla basiconica, sensilla coeloconica (types 1 and 2), and Böhm's bristles. Sensilla trichodea type 1 distributed only on male antennae; the densities of sensilla trichodea type 2 and sensilla basiconica differed between the sexes. The binding pattern of ovipositor valvulae was discovered, and one type of sensilla chaetica, two types of sensory pits, and tooth-like cones as well as two types of microtrichia were found in the ovipositor. Based on morphological evidence and research on Hymenoptera, putative functions are suggested to increase our understanding of the mechanisms by which this species finds hosts and mates, and how oviposition takes place.

A new species of Amphibulus Kriechbaumer (Hymenoptera, Ichneumonidae, Cryptinae) from Beijing with a key to species known from the Oriental and Eastern Palaearctic regions.

A new species, Amphibulus melanarius Zong, Sun & Sheng, sp.n., belonging to the tribe Phygadeuontini of the subfamily Cryptinae (Hymenoptera: Ichneumonidae), collected from Beijing, China, is reported. A key to the species of the genus Amphibulus Kriechbaumer, 1893 known in the Oriental and Eastern Palaearctic Regions is provided.

Scanning electron microscopy analysis of the cephalic sensilla of Chrysolina aeruginosa Fald. (Coleoptera, Chrysomelidae).

Chrysolina aeruginosa Fald. (Coleoptera, Chrysomelidae) is an important pest of Artemisia ordosica Krasch. In recent years, this phytophagous beetle has spread rapidly throughout northwest China, which has led to mass mortalities of the A. ordosica. This pest has caused great damage to the local ecology. To address this problem, this study compared the sensilla types and their densities on the antennae, maxillary palps, and labial palps of C. aeruginosa. Six different types of sensilla were observed on the antennae using scanning electron microscopy, i.e., sensilla chaetica, sensilla trichodea, sensilla basiconica, sensilla coeloconica, sensilla styloconica, and Böhm bristles. Sensilla chaetica were the main sensilla on the antennae. There was a significant difference in the distribution and density of sensilla trichodea between males and females. Sensilla basiconica were distributed from the fifth to the ninth flagellomeres. Sensilla coeloconica and sensilla styloconica were usually found from the fifth to the eighth flagellomeres. Böhm bristles were found only on the terminal region of the scape and pedicel. Sensilla chaetica and sensilla twig basiconica were observed on the maxillary and labial palps. Sensilla chaetica were distributed all over the maxillary and labial palps. Sensilla twig basiconica were located in the distal areas of these two types of palps. In this study, we also discussed the responses of C. aeruginosa to the volatile semiochemicals produced by their host plants and the behaviours exhibited during host and habitat selection.

Genetic structure in the seabuckthorn carpenter moth (Holcocerus hippophaecolus) in China: the role of outbreak events, geographical and host factors.

Understanding factors responsible for structuring genetic diversity is of fundamental importance in evolutionary biology. The seabuckthorn carpenter moth (Holcocerus hippophaecolus Hua) is a native species throughout the north of China and is considered the main threat to seabuckthorn, Hippophae rhamnoides L. We assessed the influence of outbreaks, environmental factors and host species in shaping the genetic variation and structure of H. hippophaecolus by using Amplified Fragment Length Polymorphism (AFLP) markers. We rejected the hypothesis that outbreak-associated genetic divergence exist, as evidenced by genetic clusters containing a combination of populations from historical outbreak areas, as well as non-outbreak areas. Although a small number of markers (4 of 933 loci) were identified as candidates under selection in response to population densities. H. hippophaecolus also did not follow an isolation-by-distance pattern. We rejected the hypothesis that outbreak and drought events were driving the genetic structure of H. hippophaecolus. Rather, the genetic structure appears to be influenced by various confounding bio-geographical factors. There were detectable genetic differences between H. hippophaecolus occupying different host trees from within the same geographic location. Host-associated genetic divergence should be confirmed by further investigation.

Scanning electron microscopy of antennal sensible of Anoplistes halodendri halodendri and Anoplistes halodendri ephippium (Coleoptera: Cerambycidae).

Anoplistes halodendri halodendri (Pallas, 1776) and Anoplistes halodendri ephippium (Stevens and Dalman, 1817) are two subspecies of the longicorn beetle A. halodendri (Coleoptera, Cerambycidae). In the recent years, these subspecies have been spreading rapidly in Hippophae rhamnoides and Hedysarum scoparium shrubberies in the Chinese provinces of Shanxi and Kingie, causing mass mortality of these shrubberies species and consequently leading to great damage to local ecological environment construction as well as high economic, ecological, and societal losses. To control their hazards effectively, here, we study and compare the types, densities, and distribution of antennal sensilla of A. h. halodendri and A. h. ephippium using scanning electron microscopy. Eight sensilla types were observed on the antennae of these two subspecies, including placoid sensilla (Ps), chaetica sensilla (ch) (types I-III), sensilla basiconica (b) (types I and II), sensilla gemmiformium (G), and auricillica sensilla (au). Ps predominated on the antennae of both A. h. halodendri and A. h. ephippium, followed by b and ch, and G and au. There were differences between the subspecies in the distribution and density of the different sensilla types, with ch I being found exclusively on the antennae of A. h. ephippium and b I and au on the antennae of A. h. halodendri only. With the exception of Ps, the densities of ch II, ch III, b II, and G on the antennae of A. h. halodendri were much higher than on the antennae of A. h. ephippium. These results provide sufficient evidence to clarify the receptive mechanisms used by these two subspecies of longicorn beetles and their responses to volatile semiochemicals released by their host plants as well as discuss their differences with respect to host and habitat selection.

Lissonota holcocerica Sheng sp.n (Hymenoptera: Ichneumonidae) parasitizing Holcocerus hippophaecolus (Lepidoptera: Cossidae) from China.

This paper describes Lissonota holcocerica Sheng sp.n. (Hymenoptera: Ichneumonidae), parasitizing Holcocerus hippophaecolus Hua, Chou, Fang and Chen (Lepidoptera: Cossidae) in Inner Mongolia, Liaoning, and Ningxia, China. The adults of L. holcocerica emerge from a cocoon during the daytime, mostly from 09:00 to 14:00 hr, then start calling and mating, mostly from 08:00 to 12:00 hr. Mating lasts from 15 sec to 15 min. The longevity of males is 5.8 ± 2.4 days, whereas for females longevity is 7.6 ± 4.6 days in the field. Nutritional supplements can significantly extend the life span of L. holcocerica. Mated females search for hosts by walking on the base of Hippophae rhamnoides L. (Rosales: Elaeagnaceae) stem infested by Ho. hippophaecolus, vibrating their antennae and tapping while searching the stem for oviposition sites. Parasitized cocoons of Ho. hippophaecolus collected in field were half the size of normal ones or even smaller.