Taxonomic clarification and neotype designation for three Indian xyleborine species (Coleoptera: Curculionidae, Scolytinae)

Xyleborini currently consists of more than 1168 species in 36 genera, nearly all of which were described in Xyleborus (Hulcr et al. 2015; Smith 2017). The tribe has been the focus of considerable taxonomic attention over the last decade resulting in phylogenetically based revisions and the erection of new genera (e.g. Hulcr et al. 2007, Hulcr and Cognato 2010). However in the Old World these efforts have largely been restricted to faunas of particular countries such as Taiwan (Beaver and Liu 2010), Thailand (Beaver et al. 2014), and Papua New Guinea (Hulcr and Cognato 2008). The region's fauna was primarily described from the 1890s to the 1940s by three authors, W.F.H. Blandford, Hans Eggers and Karl Schedl. During the 1920s to the 1940s Eggers described numerous Xyleborus species from India and Myanmar (Burma), typically from single specimens or a small series, and deposited them in the Forest Research Institute (FRI) in Dehradun, Uttarakhand, India. Cotypes (paratypes), if present for the species, were kept in his collection. Upon his death, his collection was sent to the United States National Museum of Natural History but Schedl retained many of the types that are now at the Naturhistorisches Museum Wien (NHMW). In all, FRI houses 50 xyleborine holotypes, and most of these species are solely known from the holotype.

Bark and Ambrosia Beetle (Curculionidae: Scolytinae) Diversity Found in Agricultural and Fragmented Forests in Piracicaba-SP, Brazil

Land use changes and forest fragmentation result in biodiversity loss and displacement, with insects among the most affected groups. Among these, bark beetles (Curculionidae: Scolytinae) occupy a prominent position due to their close ties to food resources, i.e., trees, and importance as primary decomposers in forest ecosystems. Therefore, our study aimed to document scolytine biodiversity associated with landscape components that vary based on their physical or botanical composition. Bark beetle diversity was sampled monthly for 12 mo in an Atlantic forest remnant and five adjacent vegetation plots (mixed Agroforestry System-AFS, of native trees and fruit species; AFS of rubber trees and coffee plants; coffee monoculture; rubber monoculture; and pasture). In total, 1,833 individuals were sampled from 38 species of which 24 (63%) were detected in very low abundance. The remaining 14 species were more abundant and widespread almost in all areas. Hypothenemus hampei (Westwood), Premnobius cavipennis (Eichhoff), Hypothenemus sp1., and Xyleborus volvulus (Fabricius) were the most abundant. The greatest abundance and richness of bark beetles were found in the dry and cold season. The varied microclimatic conditions of the vegetation plots greatly affected the diversity of the Scolytinae. Solar radiation presented a significant negative effect on abundance in almost all the studied areas. The greatest scolytine diversity was found in anthropic areas with tree canopy structure. Open areas (pasture and coffee monocrop) had a lower species diversity. Similarly, a lower abundance and species richness were found for the Atlantic forest remnant.

Recognition of a new species of <i>Carmenta</i> from New Mexico supported by morphology and mitochondrial cytochrome oxidase I data (Lepidoptera: Sesiidae: Sesiinae: Synanthedonini)

A preliminary phylogeny of 36 species of Carmenta (Lepidoptera: Sesiidae) was reconstructed based on mitochondrial cytochrome oxidase I DNA sequences using parsimony and Bayesian inference in order to assess the placement of a suspected new species. Although the phylogeny was not completely resolved, there were well-supported species groups associated with geography. Based on these results and diagnostic morphological characters, Carmenta wildishorum, n. sp., is described and illustrated from the Cimarron Mountain Range in northeastern New Mexico. The new species is sister to C. texana with a 5.2% nucleotide difference between the two, which is similar to the distance between other Carmenta species and exceeds the intraspecific difference observed within C. texana (0.3%). The phylogeny also suggests additional hidden species diversity among Carmenta species that have large geographic distributions.

Acanthotomicus sp. (Coleoptera: Curculionidae: Scolytinae), a New Destructive Insect Pest of North American Sweetgum Liquidambar styraciflua in China

A previously unknown bark beetle species, Acanthotomicus sp., has emerged as a lethal pest of American sweetgum (Liquidambar styraciflua) in China. Our survey of nursery records from around Shanghai suggests that American sweetgum have been under heavy attack since at least 2013, resulting in the death of > 10,000 trees. Mass attacks of the apparently sweetgum-specific Acanthotomicus sp. can be diagnosed by accumulation of resinous exudates on the trunk, wilted foliage, and eventual numerous exit holes of the new generation. A Chinese native sweetgum Liquidambar formosana can also be colonized by Acanthotomicus sp. This pest is of concern not only as a killer of sweetgum in the Chinese nursery trade but also as a potentially destructive invasive pest of sweetgum in North America. This discovery suggests that global preinvasion assessment of pests is warranted.

PCR Multiplexes Discriminate Fusarium Symbionts of Invasive Euwallacea Ambrosia Beetles that Inflict Damage on Numerous Tree Species Throughout the United States

Asian Euwallacea ambrosia beetles vector Fusarium mutualists. The ambrosial fusaria are all members of the ambrosia Fusarium clade (AFC) within the Fusarium solani species complex (FSSC). Several Euwallacea-Fusarium mutualists have been introduced into nonnative regions and have caused varying degrees of damage to orchard, landscape, and forest trees. Knowledge of symbiont fidelity is limited by current identification methods, which typically requires analysis of DNA sequence data from beetles and the symbionts cultured from their oral mycangia. Here, polymerase chain reaction (PCR)-based diagnostic tools were developed to identify the six Fusarium symbionts of exotic Euwallacea spp. currently known within the United States. Whole-genome sequences were generated for representatives of six AFC species plus F. ambrosium and aligned to the annotated genome of F. euwallaceae. Taxon-specific primer-annealing sites were identified that rapidly distinguish the AFC species currently within the United States. PCR specificity, reliability, and sensitivity were validated using a panel of 72 Fusarium isolates, including 47 reference cultures. Culture-independent multiplex assays accurately identified two AFC fusaria using DNA isolated from heads of their respective beetle partners. The PCR assays were used to show that Euwallacea validus is exclusively associated with AF-4 throughout its sampled range within eastern North America. The rapid assay supports federal and state agency efforts to monitor spread of these invasive pests and mitigate further introductions.

The evolution of Batesian mimicry within the North American Asidini (Coleoptera: Tenebrionidae)

The asidine darkling beetles (Coleoptera: Tenebrionidae: Asidini) are a diverse tribe of flightless tenebrionids found in many arid and sub-arid habitats around the world. The 263 currently described North American species are contained in ten genera, all of which are restricted to the western half of the continent. The Asidini, like all members of the subfamily Pimeliinae, lack defensive glands. Instead, several phenotypic traits occur within the tribe that may help limit predation. These include the contrasting defensive strategies of crypsis, through either background matching or pattern disruption, and Batesian mimicry of the chemically defended genus Eleodes. Dorsal elytral morphology was assessed between 53 North American asidine species and 13 common Eleodes model species using multiple methodologies to assess similarities between species in the two groups that might indicate mimetic relationships. A phylogeny of the North American asidines is used to map the occurrence of differing defensive strategies within the tribe. Crypsis is reconstructed as the ancestral state, with two origins for Batesian mimicry and multiple reversals. The combination of strongly to weakly cryptic species and varying levels of mimetic fidelity to Eleodes model species make the asidines a promising lineage upon which to further explore the evolution of defensive phenotypes.

History of the Exotic Ambrosia Beetles Euwallacea interjectus and Euwallacea validus (Coleoptera: Curculionidae: Xyleborini) in the United States

Exotic insects are constantly intercepted at U.S. ports-of-entry. Of these, wood-boring beetles, particularly xyleborine ambrosia beetles, are sometimes missed during port inspections and become established in the United States. Euwallacea validus (Eichhoff) and Euwallacea interjectus (Blandford) are morphologically similar Asian ambrosia beetle species that vary by their fungal associates and their potential to cause economic damage. Euwallacea validus and E. interjectus were first discovered in New York (1975) and Hawaii (1976), respectively. Euwallacea validus was collected multiple times from widely separated localities and is assumed to have spread throughout the eastern United States. The discovery of E. interjectus in Florida (2011) and Texas (2011) prompted our review of the E. validus specimens because of the potential misidentification of the species. In addition, using mitochondrial cytochrome oxidase I (COI) DNA data and phylogenetic analysis, we tested the hypothesis that multiple introductions account for the U.S. populations of E. interjectus and E. validus. Our review of 7,184 specimens revealed an earlier introduction to the mainland for E. interjectus, which was first collected from Louisiana in 1984. This species is distributed in the South while E. validus occurs in the North with a known area of syntopy in northeastern Georgia. The extent of the syntopy within the United States is unknown and further investigation is required. Phylogenetic analysis of 24 E. interjectus and 20 E. validus individuals resolved clades that associated with each species and gross geographic provenance. Four well-supported clades represented E. interjectus which included the following localities: 1) Hawaii and Thailand; 2) Vietnam, Taiwan, and Texas; 3) Okinawa (Japan); and 4) Japan and several southern U.S. states. One clade comprised all E. validus specimens from Japan and the mainland United States. Four and two haplotypes were found for the E. interjectus and E. validus specimens, respectively, in mainland United States. Except for the Texas specimen, the haplotypes differed by one nucleotide. The relationship of the haplotypes and their sequence similarity suggested that the provenance of E. validus and the majority of E. interjectus haplotypes was Japan while the Texas haplotype originated later and from a location near Taiwan. Given the high nucleotide sequence difference between the Hawaiian and Thai haplotypes, the exact origin of the Hawaiian E. interjectus is unknown but likely Southeast Asia. A broader investigation including more SE Asian individuals will help to further explain the introduction of E. interjectus into Hawaii and Texas.

A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae)

The Nearctic bark beetle genus Scolytus Geoffroy was revised based in part on a molecular and morphological phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear (28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided mixed results while Bayesian analysis recovered most nodes with posterior probabilities >90%. Native hardwood- and conifer-feeding Scolytus species were recovered as paraphyletic. Native Nearctic species were recovered as paraphyletic with hardwood-feeding species sister to Palearctic hardwood-feeding species rather than to native conifer-feeding species. The Nearctic conifer-feeding species were monophyletic. Twenty-five species were recognized. Four new synonyms were discovered: Scolytuspraeceps LeConte, 1868 (= Scolytusabietis Blackman, 1934; = Scolytusopacus Blackman, 1934), Scolytusreflexus Blackman, 1934 (= Scolytusvirgatus Bright, 1972; = Scolytuswickhami Blackman, 1934). Two species were reinstated: Scolytusfiskei Blackman, 1934 and Scolytussilvaticus Bright, 1972. A diagnosis, description, distribution, host records and images were provided for each species and a key is presented to all species.

Classification of weevils as a data-driven science: leaving opinion behind

Data and explicit taxonomic ranking criteria, which minimize taxonomic change, provide a scientific approach to modern taxonomy and classification. However, traditional practices of opinion-based taxonomy (i.e., mid-20(th) century evolutionary systematics), which lack explicit ranking and naming criteria, are still in practice despite phylogenetic evidence. This paper discusses a recent proposed reclassification of weevils that elevates bark and ambrosia beetles (Scolytinae and Platypodinae) to the ranks of Family. We demonstrate that the proposed reclassification 1) is not supported by an evolutionary systematic justification because the apparently unique morphology of bark and ambrosia beetles is shared with other unrelated wood-boring weevil taxa; 2) introduces obvious paraphyly in weevil classification and hence violates good practices on maintaining an economy of taxonomic change; 3) is not supported by other taxonomic naming criteria, such as time banding. We recommend the abandonment of traditional practices of an opinion-based taxonomy, especially in light of available data and resulting phylogenies.

Coptoborus ochromactonus, n. sp. (Coleoptera: Curculionidae: Scolytinae), an emerging pest of cultivated balsa (Malvales: Malvaceae) in Ecuador

A new species of xyleborine ambrosia beetle has been found to attack balsa, Ochroma pyramidale (Cavanilles ex Lamarck) Urban, in Ecuador. Coptoborus ochromactonus Smith & Cognato is described and its biology is reported. Large-scale surveys were conducted between 2006 and 2009, and observational studies were carried out between 2010 and 2013 in Ecuadorian commercial plantations to determine life history and host preference characteristics. C. ochromactonus attacked balsa between 1.5 and 3 yr in age. Successful attacks were more prevalent in smaller diameter trees and unhealthy trees. In general, attacks and beetle-caused mortality were more prevalent during the dry summer months when trees were under more moisture and light stress. Fungal mycelia were consistently observed coating beetle galleries and are likely the true damaging agent to balsa trees.

Species boundaries and host range of tortoise mites (Uropodoidea) phoretic on bark beetles (Scolytinae), using morphometric and molecular markers

Understanding the ecology and evolutionary history of symbionts and their hosts requires accurate taxonomic knowledge, including clear species boundaries and phylogenies. Tortoise mites (Mesostigmata: Uropodoidea) are among the most diverse arthropod associates of bark beetles (Curculionidae: Scolytinae), but their taxonomy and host associations are largely unstudied. We tested the hypotheses that (1) morphologically defined species are supported by molecular data, and that (2) bark beetle uropodoids with a broad host range comprise cryptic species. To do so, we assessed the species boundaries of uropodoid mites collected from 51 host species, across 11 countries and 103 sites, using morphometric data as well as partial cytochrome oxidase I (COI) and nuclear large subunit ribosomal DNA (28S). Overall, morphologically defined species were confirmed by molecular datasets, with a few exceptions. Twenty-nine of the 36 uropodoid species (Trichouropoda, Nenteria and Uroobovella) collected in this study had narrow host ranges, while seven species had putative broad host ranges. In all but one species, U. orri, our data supported the existence of these host generalists, which contrasts with the typical finding that widespread generalists are actually complexes of cryptic specialists.

Molecular phylogeny of bark and ambrosia beetles reveals multiple origins of fungus farming during periods of global warming

BACKGROUND

Fungus farming is an unusual life style in insects that has evolved many times in the wood boring weevils named 'ambrosia beetles'. Multiple occurrences of this behaviour allow for a detailed comparison of the different origins of fungus farming through time, its directionality, and possible ancestral states. We tested these hypotheses with a phylogeny representing the largest data set to date, nearly 4 kb of nucleotides from COI, EF-1α, CAD, ArgK, 28S, and 200 scolytine taxa.

RESULTS

Phylogenetic analyses using Bayesian or parsimony approaches placed the root of Scolytinae close to the tribe Scolytini and Microborus, but otherwise indicated low resolution at older nodes. More recent clades were well resolved, including ten origins of fungus farming. There were no subsequent reversals to bark or phloem feeding in the fungus farming clades. The oldest origin of fungus farming was estimated near 50 Ma, long after the origin of Scolytinae (100-120 Ma). Younger origins included the species rich Xyleborini, dated to 21 Ma. Sister group comparisons and test of independence between traits indicated that neither gregarious larval feeding nor regular inbreeding by sibling mating was strongly correlated with the origin of fungus farming.

CONCLUSION

Origins of fungus farming corresponded mainly with two periods of global warming in the Cenozoic era, which were characterised by broadly distributed tropical forests. Hence, it seems likely that warm climates and expanding tropical angiosperm forests played critical roles in the successful radiation of diverse fungus farming groups. However, further investigation will likely reveal additional biological factors that promote fungus farming.

The age and phylogeny of wood boring weevils and the origin of subsociality

A large proportion of the hyperdiverse weevils are wood boring and many of these taxa have subsocial family structures. The origin and relationship between certain wood boring weevil taxa has been problematic to solve and hypotheses on their phylogenies change substantially between different studies. We aimed at testing the phylogenetic position and monophyly of the most prominent wood boring taxa Scolytinae, Platypodinae and Cossoninae, including a range of weevil outgroups with either the herbivorous or wood boring habit. Many putatively intergrading taxa were included in a broad phylogenetic analysis for the first time in this study, such as Schedlarius, Mecopelmus, Coptonotus, Dactylipalpus, Coptocorynus and allied Araucariini taxa, Dobionus, Psepholax, Amorphocerus-Porthetes, and some peculiar wood boring Conoderini with bark beetle behaviour. Data analyses were based on 128 morphological characters, rDNA nucleotides from the D2-D3 segment of 28S, and nucleotides and amino acids from the protein encoding gene fragments of CAD, ArgK, EF-1α and COI. Although the results varied for some of the groups between various data sets and analyses, one may conclude the following from this study: Scolytinae and Platypodinae are likely sister lineages most closely related to Coptonotus; Cossoninae is monophyletic (including Araucariini) and more distantly related to Scolytinae; Amorphocerini is not part of Cossoninae and Psepholax may belong to Cryptorhynchini. Likelihood estimation of ancestral state reconstruction of subsociality indicated five or six origins as a conservative estimate. Overall the phylogenetic results were quite dependent on morphological data and we conclude that more genetic loci must be sampled to improve phylogenetic resolution. However, some results such as the derived position of Scolytinae were consistent between morphological and molecular data. A revised time estimation of the origin of Curculionidae and various subfamily groups were made using the recently updated fossil age of Scolytinae (100 Ma), which had a significant influence on node age estimates.

Repeated evolution of crop theft in fungus-farming ambrosia beetles

Ambrosia beetles, dominant wood degraders in the tropics, create tunnels in dead trees and employ gardens of symbiotic fungi to extract nutrients from wood. Specificity of the beetle-fungus relationship has rarely been examined, and simple vertical transmission of a specific fungal cultivar by each beetle species is often assumed in literature. We report repeated evolution of fungal crop stealing, termed mycocleptism, among ambrosia beetles. The mycocleptic species seek brood galleries of other species, and exploit their established fungal gardens by tunneling through the ambient mycelium-laden wood. Instead of carrying their own fungal sybmbionts, mycocleptae depend on adopting the fungal assemblages of their host species, as shown by an analysis of fungal DNA from beetle galleries. The evidence for widespread horizontal exchange of fungi between beetles challenges the traditional concept of ambrosia fungi as species-specific symbionts. Fungus stealing appears to be an evolutionarily successful strategy. It evolved independently in several beetle clades, two of which have radiated, and at least one case was accompanied by a loss of the beetles' fungus-transporting organs. We demonstrate this using the first robust phylogeny of one of the world's largest group of ambrosia beetles, Xyleborini.

Notes on Scolytus fagi Walsh 1867 with the ignation of a neotype, distribution notes and Key to Scolytus Geoffroy of America east the Mississippi River (Coleoptera, Curculionidae, Scolytinae, Scolytini)

The identification of Scolytus fagi Walsh has been difficult because of the lack of diagnostic literature, the occurrence of several morphologically similar sympatric Scolytus species and the loss of the syntypes. In an effort to reduce taxonomic confusion, we designate a neotype for Scolytus fagi, redescribe the male and female, add new distributional records and create a key for the identification of eastern Scolytus species.

Resurrection of Dryotomicus Wood and description of two new species from the Amazon River Basin (Coleoptera, Curculionidae, Scolytinae, Phloeotribini)

A cladistic analysis based on 20 morphological characters was conducted for 11 species representing two valid and two synonymized Phloeotribini genera. One hundred-eighty most-parsimonious trees were recovered and the Dryotomicus Wood species were monophyletic in a mostly unresolved strict-consensus tree. The unusual antennal morphology, with the length of the first two funicular segments equal to the last three segments and a scape which is twice the length of the funicle, distinguish Dryotomicus from the other Phloeotribini genera. Hence this genus is resurrected because of monophyly and diagnostic characters. Dryotomicus oenophilissp. n. and Dryotomicus woodrexsp. n. are described from Guyana and Peru, respectively. In the male specimen of Dryotomicus oenophilis, the frons has one median and two large lateral carinae and in the male specimen of Dryotomicus woodrex, the frons has three smaller median tubercles arranged transversely. Phloeotribus puberulus Chapuis and Phloeotribus tuberculatus (Eggers) were monophyletic with the new Dryotomicus species and thus are transferred to this genus. Keys to the Phloeotribini genera and Dryotomicus species are given.

Species composition, seasonal activity, and semiochemical response of native and exotic bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in northeastern Ohio

In 2007, we surveyed the alien and endemic scolytine (bark and ambrosia beetles) fauna of northeastern Ohio, and for the most abundant species, we characterized their seasonal activity and response to three semiochemical baits. In total ,5,339 scolytine beetles represented by 47 species and 29 genera were caught in Lindgren funnel traps. Three species constituted 57% of the total catch, including Xylosandrus germanus (Blandford), Tomicus piniperda (L.), and Dryocoetes autographus (Ratzeburg). Of the total captured, 32% of the species and approximately 60% of the individuals were exotic, suggesting that exotic species numerically dominate the scolytine fauna in some urban areas. More native and exotic species were caught in traps baited with ethanol alone than in traps baited with other lures. However, significantly more individuals, especially of T. piniperda, D. autographus, Gnathotrichus materiarius (Fitch), and Ips grandicollis (Eichhoff), and species were caught in traps baited with ethanol plus alpha-pinene than in traps baited with ethanol alone or the exotic Ips lure. This suggests that among these baits, the ethanol plus alpha-pinene baits may be useful in maximizing scolytine beetle catches of these species within this region. Species diversity and richness for both native and exotic beetles was greatest in traps baited with ethanol alone. The period of peak trap capture varied depending upon species: X. germanus was most abundant in traps in mid-May and early-August; T. piniperda in mid-May; D. autographus in early June, mid-July, and mid-September; Anisandrus sayi Hopkins and G. materiarius in mid-May, mid-July, and early September; and I. grandicollis in early April, mid-July, and late September.

DNA identification confirms pecan weevil (Coleoptera: Curculionidae) infestation of Carpathian walnut

Larvae found infesting fruit from a Carpathian walnut, Juglans regia L., tree in Missouri were confirmed by DNA analysis to be those of pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae). The infested walnut tree occurs in the midst of pecan weevil-infested pecans, Carya illinoinensis (Wang.) K. Koch; the larval haplotypes were found to be identical to pecan weevil larvae from the region, indicating that the walnut infestation arose by association with infested pecan. This is the first confirmed DNA analysis showing pecan weevil attacks J. regia and the second report that J. regia may be at risk of infestation by pecan weevil. Further study indicates this infestation on walnut is established and ongoing. The pecan weevil is a key pest of pecan and seems capable of inflicting similar damage to walnut if spread to commercial areas that produce J. regia.

Polyphyly of Xylosandrus Reitter inferred from nuclear and mitochondrial genes (Coleoptera: Curculionidae: Scolytinae)

The Xyleborina ambrosia beetle genus Xylosandrus contains 54 species, several of which are of economic importance. The monophyly of the genus was tested using a data set comprised of multiple gene loci: 28S rDNA; the mitochondrial gene cytochrome oxidase I (COI); and the nuclear genes arginine kinase (ArgK), rudimentary (CAD), and Elongation Factor 1alpha (EF-1alpha). The nuclear protein-coding genes CAD and ArgK were used for the first time in phylogenetics of Scolytinae. Analyses were performed using Parsimony and Bayesian optimality criteria. Our analyses included 43 specimens representing 15 Xylosandrus species and 20 species from Amasa, Anisandrus, Cnestus, Euwallacea and Xyleborus, and two species from the outgroup genus Coccotrypes. All analyses recovered a polyphyletic Xylosandrus. Several species of Xylosandrus were consistently placed in clades with the genera Anisandrus and Cnestus with high support values (100% bootstrap support). Among these, was the economically important invasive species X. mutilatus, which was consistently recovered as part of the "Cnestus" clade. In our analyses, both CAD and ArgK demonstrated phylogenetic utility across varying nodal depths. Despite the selection of genes with signals at complementary phylogenetic depths, the data set used herein did not resolve the phylogeny of Xylosandrus and related genera. Since the taxon sample available for molecular work represents only a fraction of Xylosandrus species, a complete revision that combines molecular and morphological data in a total evidence approach is recommended for the genus.