A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China

New species and newly recorded species of Anisandrus Ferrari, 1867 ambrosia beetles from Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

Five new species, Anisandrusmontanussp. nov., A.phithakpasp. nov., A.tanaosisp. nov., A.tritonsp. nov., and A.uniseriatussp. nov. are described from Thailand. Anisandruscarinensis (Eggers, 1923) is reported from Thailand for the first time and A.apicalis is removed from the Thai fauna. With the inclusion of the species described and recorded here, the diversity of Anisandrus is increased to 40 species, of which 11 occur in Thailand. A synoptic list and a key to the Anisandrus of Thailand are presented.

New records of non-native Coleoptera in Italy

Background

In the last decades, climate change and globalisation have been exacerbating the introduction of non-native beetles worldwide. Due toits peculiar territory, climate and geographical position in the middle of the Mediterranean Basin, Italy is one of the European countries with the highest number of intercepted, adventive and established non-native beetles, some of which are invasive. In this perspective, producing new faunistic records and continuously updating reliable and easily accessible distributional data is a fundamental step in investigating and potentially preventing further species introduction.

New information

The aim of this contribution is to report and discuss new faunistic records of non-native Coleoptera in Italy. For some species, new records enlarge the previously-known distribution (e.g. the ambrosia beetles Anisandrusmaiche (Kurentzov, 1941) and Cnestusmutilatus (Blandford, 1894) or the click beetle Monocrepidiusposticus (Eschscholtz, 1829)), while for others (e.g. the scarab beetle Archophileurusspinosus Dechambre, 2006), data confirm their establishment and highlight a possible expansion phase. The false powderpost beetles Ptilineurusmarmoratus (Reitter, 1877) and the longhorn beetle Xylotrechuschinensis (Chevrolat, 1852) are two new additions to the Italian fauna, while the establishment of the monotomid beetle Monotomaamericana Aubé 1837 is confirmed.

An accurate, efficient, and economical identification technology for black twig borer based on species-specific cytochrome C oxidase subunit I PCR assay

Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) is a worldwide invasive species that causes huge economic loss and environmental damage in many countries. Traditional morphological characteristics make it hard to identify scolytines due to their tiny size. Besides, the intercepted insect samples are incomplete, and the limitation of insect (larvae and pupae) morphology makes morphological identification more difficult. The majority of the damage is caused by adults and fungi that serve as nutrition for their larvae. They destroy plant trunks, branches, and twigs, affecting plant transport tissues in both weak and healthy plants. An accurate, efficient, and economical molecular identification technique for X. compactus not restricted by professional taxonomic knowledge is necessary. In the present study, a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI) was developed. A species-specific COI (SS-COI) PCR assay was designed to identify X. compactus regardless of the developmental stage. Twelve scolytines commonly found in eastern China, namely Xylosandrus compactus, X. crassiusculus, X. discolor, X. germanus, X. borealis, X. amputates, X. eupatorii, X. mancus, Xyleborinus saxesenii, Euwallacea interjectus, E. fornicatus, and Acanthotomicus suncei, were included in the study. Additionally, specimens of X. compactus from 17 different areas in China, as well as a specimen collected from the United Stated, were also analyzed. Results demonstrated the accuracy and high efficiency of the assay, regardless of the developmental stage or the type of specimen. These features provide a good application prospect for fundamental departments and can be used to prevent the harmful consequences of the spread of X. compactus.

Lethal and sublethal effects of synthetic and bioinsecticides toward the invasive ambrosia beetle Xylosandrus compactus

BACKGROUND

Exotic ambrosia beetles are emerging widespread pests of several wild and managed trees and shrubs. Xylosandrus compactus (Eichhoff) is one of the most invasive species causing damage to a broad range of host plants. Little information is available on its control, including the impact of insecticides. Bioassays were conducted to evaluate the potential of four bioinsecticides and seven synthetic insecticides in controlling X. compactus. Beetle mortality and sublethal effects on tunneling, cultivation of the mutualist fungus and reproduction were assessed.

RESULTS

Concentration-mortality curves were determined for all tested insecticides. Lambda-cyhalothrin was the most toxic insecticide, showing the lowest estimated 90% and 50% lethal concentrations (LC₉₀ and LC₅₀ ), followed by deltamethrin and thiamethoxam. Acetamiprid caused the highest levels of mortality and brood size reduction under extended laboratory conditions. Moreover, acetamiprid, thiamethoxam and lambda-cyhalothrin caused the greatest mortality and, together with deltamethrin, strongly affected progeny occurrence inside infested galleries and beetle brood size. Among the bioinsecticides, pyrethrins significantly affected beetle survival under laboratory conditions, but not brood size in extended laboratory bioassays. Some of the tested insecticides had significant lethal and sublethal effects only when beetles were exposed to fresher residues, highlighting differences in toxicity persistence.

CONCLUSION

This study provides first baseline toxicity data for synthetic insecticides and bioinsecticides with different modes of action and origin toward X. compactus, and the first evidence that several insecticides can cause multiple sublethal effects on this pest. These findings can help in building suitable integrated pest management packages against this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Spatiotemporal Distributions of Scolytinae Beetles in the Subtropical Forests of Southern China

Scolytinae beetles serve as important regulators of ecosystem integrity. However, some of these species have been identified as important pests. The Guangdong region of China exhibits unique geographic characteristics, but is also subject to substantial anthropogenic disturbances, making it an important region for ecological research. This study was designed to assess the biodiversity and abundance of these Scolytinae beetles in subtropical areas, to define indicators associated with environmental disturbances, and to thereby provide additional valuable information that can support the conservation of the ecosystem and the monitoring and controling of pest species. For these analyses, a two-season survey of Scolytinae communities was performed across three habitats to examine the patterns of variation within these communities. These analyses revealed that environmental disturbances were associated with a drop in Scolytinae beetle population diversity, with Hypothenemus sp.2, Xyleborinus andrewesi, and Xyleborinus artestriatus offering particular value as indicators associated with severe environmental disruptions. Plant diversity and composition also impacted Scolytinae beetle communities through a range of complex mechanisms. Scolytinae beetle diversity was also found to be higher during the rainy season relative to the dry season, with beetle abundance being responsive to average temperatures, but unrelated to average relative humidity levels.

 Tricosa uniseriata, a new species of xyleborine ambrosia beetle from Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

A new species, Tricosa uniseriatasp. nov., is described here. A list of Tricosa species found in Thailand with distributions and an updated key to Tricosa are also provided.

New species and new records of exotic Scolytinae (Coleoptera, Curculionidae) in Europe

Background

Bark and ambrosia beetles (Coleoptera, Scolytinae) are amongst the most important wood-boring insects introduced to Europe. During field investigations conducted between 2019 and 2021 in different countries and regions of Europe, many exotic species have been recorded providing new and relevant data.

New information

Dryoxylononoharaense (Murayama, 1933) is recorded in Europe for the first time. Xyleborinusattenuatus (Blandford, 1894) is a species new to Italy, while Xylosandrusgermanus (Blandford, 1894), Hypothenemuseruditus (Westwood, 1836) and Amasa sp. near A.truncata are new country records for Portugal. Cnestusmutilatus (Blandford, 1894), Phloeotribusliminaris (Harris, 1852) were collected in Italy and Amasa sp. near A.truncata was collected in France after the first discovery, confirming their establishment and their dispersal into new areas.

First complete mitochondrial genome from the genus Coptodryas (Coleoptera: Curculionidae: Scolytinae) and its phylogenetic implications

The complete mitochondrial genome (mitogenome) of Coptodryas elegans was determined, which represents the first sequenced mitogenome from Coptodryas. This mitogenome is 15,959 bp in size and comprises 36 typical coding genes and a control region, the tRNA^Ile was not detected in this mitogenome, as observed in other species of Curculionidae. The monophyly of the family Scolytinae and the sister relationship between C. elegans and Cyclorhipidion bodoanus is supported by maximum likelihood analysis derived from the protein-coding gene sequences.

Revision of the xyleborine ambrosia beetle genus Microperus Wood, 1980 (Curculionidae, Scolytinae, Xyleborini) of Thailand with four new species and four newly recorded species

Microperus Wood, 1980 ambrosia beetles in Thailand are reviewed. Four species, M.bidentatussp. nov., M.bucolicussp. nov., M.globodeclivissp. nov., and M.serratussp. nov. are described. Four new combinations are given: Microperusarmaticeps (Schedl, 1942) comb. nov., Microperusexsculptus (Eggers, 1927) comb. nov., Microperuspedellus (Schedl, 1969) comb. nov., and Microperusspicatulus (Browne, 1986) comb. nov., stat. res., all from Xyleborus. Two new synonyms are proposed: Microperuscruralis (Schedl, 1975) (= Xyleborusmyllus Browne, 1986 syn. nov.), Microperusexsculptus (Eggers, 1927) (= Xyleborusdentipennis Browne, 1983 syn. nov.). Four species are reported from Thailand for the first time: Microperuschrysophylli (Eggers, 1930), Microperusexsculptus, Microperusnanus (Browne, 1949) and Microperusquercicola (Eggers, 1926). With the inclusion of the Microperus species described and recorded herein, the diversity of Microperus is increased to 35 species, of which 18 are recorded in Thailand. An updated key to the Microperus of the Indochinese Peninsula and China is provided. The taxonomy, diagnostic characters, and distribution of species are briefly discussed.

Comparative Analysis of Eight Mitogenomes of Bark Beetles and Their Phylogenetic Implications

Simple Summary

Many bark beetles are destructive pests in coniferous forests and cause extensive ecological and economic losses worldwide. Comparative studies of the structural characteristics of mitogenomes and phylogenetic relationships of bark beetles can improve our understanding of mitogenome evolution. In this study, we sequenced eight mitogenomes of bark beetles. Our results show that the use of start and stop codons, the abundance of amino acids, and the relative frequency of codon use are conserved among the eight bark beetles. Different regions of tRNA exhibit different degrees of conservatism. Together with the analysis of evolutionary rates and genetic distance among bark beetle species, our results reveal phylogenetic relationships among bark beetles of the subfamily Scolytinae.

Abstract

Many bark beetles of the subfamily Scolytinae are the most economically important insect pests of coniferous forests worldwide. In this study, we sequenced the mitochondrial genomes of eight bark beetle species, including Dendroctonus micans, Orthotomicus erosus, Polygraphus poligraphus, Dryocoetes hectographus, Ips nitidus, Ips typographus, Ips subelongatus, and Ips hauseri, to examine their structural characteristics and determine their phylogenetic relationships. We also used previously published mitochondrial genome sequence data from other Scolytinae species to identify and localize the eight species studied within the bark beetle phylogeny. Their gene arrangement matched the presumed ancestral pattern of these bark beetles. Start and stop codon usage, amino acid abundance, and the relative codon usage frequencies were conserved among bark beetles. Genetic distances between species ranged from 0.037 to 0.418, and evolutionary rates of protein-coding genes ranged from 0.07 for COI to 0.69 for ND2. Our results shed light on the phylogenetic relationships and taxonomic status of several bark beetles in the subfamily Scolytinae and highlight the need for further sequencing analyses and taxonomic revisions in additional bark beetle species.

Xylosandrus germanus (Blandford, 1894) on Grapevines in Italy with a Compilation of World Scolytine Weevils Developing on Vitaceae

The invasive ambrosia beetle Xylosandrus germanus (Curculionidae: Scolytinae: Xyleborini) is recorded for the first time infesting wine grapes in Italy. The type of the attack is illustrated and the possible causes of the onset of the infestation are discussed. Furthermore, given the continuously increasing number of alien wood-borer beetles introduced worldwide, we provide and discuss the updated world checklist of Scolytinae attacking Vitaceae, and Vitis sp. in particular.

Native or Invasive? The Red-Haired Pine Bark Beetle Hylurgus ligniperda (Fabricius) (Curculionidae: Scolytinae) in East Asia

The red-haired pine bark beetle, Hylurgus ligniperda (Fabricius), is one of the most rapidly spreading invasive forest insects. Originally from Eurasia, it has subsequently been introduced to Oceania, North, and South America. Yet, the status of H. ligniperda in East Asia is ambiguous. Here, investigation and analysis were conducted on the beetle in China, South Korea, and Japan. New occurrences in China and South Korea were recorded by field surveys and the expansion of H. ligniperda spreading in East Asia was analyzed. The results show that H. ligniperda is likely an invasive species in East Asia, initially invading Japan, then South Korea. Now it has invaded and successfully colonized Shandong province, China. Furthermore, the species has spread rapidly and it is now widely distributed in South Korea and Japan.

A revision of the Neotropical genus Coptoborus Hopkins (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

The Neotropical xyleborine ambrosia beetle genus Coptoborus Hopkins is reviewed. The following 40 Coptoborus species are described: C. amplissimus sp. nov. (Peru), C. asperatus sp. nov. (Ecuador), C. barbicauda sp. nov. (French Guiana), C. bettysmithae sp. nov. (Ecuador), C. brevicauda sp. nov. (Ecuador), C. brigman sp. nov. (Ecuador), C. busoror sp. nov. (Ecuador), C. capillisoror sp. nov. (Brazil), C. chica sp. nov. (Suriname), C. crassisororcula sp. nov. (Peru), C. doliolum sp. nov. (Ecuador), C. erwini sp. nov. (Ecuador), C. furiosa sp. nov. (Ecuador), C. galacatosae sp. nov. (Ecuador), C. hansen sp. nov. (Brazil), C. incomptus sp. nov. (Peru), C. janeway sp. nov. (Peru), C. katniss sp. nov. (Ecuador), C. leeloo sp. nov. (Ecuador), C. leia sp. nov. (Ecuador, Suriname), C. leporinus sp. nov. (Peru), C. martinezae sp. nov. (Ecuador), C. murinus sp. nov. (Ecuador), C. newt sp. nov. (Peru), C. osbornae sp. nov. (Ecuador), C. panosus sp. nov. (French Guiana), C. papillicauda sp. nov. (Suriname), C. pilisoror sp. nov. (Ecuador), C. ripley sp. nov. (Ecuador), C. sagitticauda sp. nov. (Guyana), C. sarahconnor sp. nov. (Brazil), C. scully sp. nov. (Ecuador), C. sicula sp. nov. (Ecuador), C. sororcula sp. nov. (Peru), C. starbuck sp. nov. (Ecuador), C. trinity sp. nov. (Brazil), C. uhura sp. nov. (Peru), C. vasquez sp. nov. (Panama), C. vrataski sp. nov. (Brazil), and C. yar sp. nov. (Ecuador). Seventeen new combinations are given: Coptoborus amazonicus (Petrov, 2020) comb. nov., C. atlanticus (Bright & Torres, 2006) comb. nov., C. bellus Bright & Torres, 2006 comb. nov., C. coartatus (Sampson, 1921) comb. nov., C. crinitulus (Wood, 1974) comb. nov., C. exilis (Schedl, 1934) comb. nov., C. incultus (Wood, 1975) comb. nov., C. magnus (Petrov, 2020) comb. nov., C. micarius (Wood, 1974) comb. nov., C. obtusicornis (Schedl, 1976) comb. nov., C. paurus (Wood, 2007) comb. nov., C. pristis (Wood, 1974) comb. nov., C. pseudotenuis (Schedl, 1936) comb. nov., C. puertoricensis (Bright & Torres, 2006) comb. nov., C. ricini (Eggers, 1932) comb. nov., C. semicostatus (Schedl, 1948) comb. nov., C. tristiculus (Wood, 1975) comb. nov., and C. villosulus (Blandford, 1898) comb. nov. Two new synonyms are proposed: Coptoborus Hopkins, 1915 (= Theoborus Hopkins, 1915 syn. nov.) and Coptoborus villosulus (Blandford, 1898) (= Theoborus theobromae Hopkins, 1915 syn. nov.). Xyleborus neosphenos Schedl, 1976 comb. res. is removed from Coptoborus. The revised genus now contains 77 species and a key to their identification is provided.

TaqMan probe assays on different biological samples for the identification of three ambrosia beetle species, Xylosandrus compactus (Eichoff), X. crassiusculus (Motschulsky) and X. germanus (Blandford) (Coleoptera Curculionidae Scolytinae)

Molecular assays based on qPCR TaqMan Probes were developed to identify three species of the genus Xylosandrus, X. compactus, X. crassiusculus and X. germanus (Coleoptera Curculionidae Scolytinae). These ambrosia beetles are xylophagous species alien to Europe, causing damages to many ornamental and fruiting trees as well as shrubs. DNA extraction was carried out from adults, larvae and biological samples derived from insect damages on infested plants. For X. compactus, segments of galleries in thin infested twigs were cut and processed; in the case of X. crassiusculus, raw frass extruded from exit holes was used, while DNA of X. germanus was extracted from small wood chips removed around insect exit holes. The assays were inclusive for the target species and exclusive for all the non-target species tested. The LoD was 3.2 pg/µL for the frass of X. crassiusculus and 0.016 ng/µL for the woody matrices of the other two species. Both repeatability and reproducibility were estimated on adults and woody samples, showing very low values ranging between 0.00 and 4.11. Thus, the proposed diagnostic assays resulted to be very efficient also on the woody matrices used for DNA extraction, demonstrating the applicability of the protocol in the absence of dead specimens or living stages.

Laurel Wilt: Current and Potential Impacts and Possibilities for Prevention and Management

In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.