Sarah M. Smith

Effects of Chipping, Grinding, and Heat on Survival of Emerald Ash Borer, Agrilus planipennis (Coleoptera: Buprestidae), in Chips

Abstract The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), a phloem-feeding insect from Asia, was identified in 2002 as the cause of widespread ash (Fraxinus sp.) mortality in southeastern Michigan and Essex County, Ontario. Most larvae overwinter as nonfeeding prepupae in the outer sapwood or thick bark of large trees. In a series of studies, we evaluated effects of grinding, chipping, and heat treatment on survival of A. planipennis prepupae in ash material. Heavily infested ash bolts containing roughly 8,700 prepupae were processed by a horizontal grinder with either a 2.5- or 10-cm screen. There was no evidence of A. planipennis survival in chips processed with the 2.5-cm screen, but eight viable prepupae were recovered from chips processed with the 10-cm screen. We chiseled additional sentinel chips with prepupae from ash logs and buried 45 in each chip pile. In total, six prepupae in sentinel chips survived the winter, but we found no sign of adult A. planipennis emergence from the processed chips. Subsequently, we assessed prepupal survival in chips processed by a chipper or a horizontal grinder fit with 5-, 10-, or 12.7-cm screens. An estimated 1,565 A. planipennis prepupae were processed by each treatment. Chips from the chipper were shorter than chips from the grinder regardless of the screen size used. No live prepupae were found in chips produced by the chipper, but 21 viable prepupae were found in chips from the grinder. Infested wood and bark chips chiseled from logs were held in ovens at 25, 40, or 60°C for 8, 24, or 48 h. Prepupal survival was consistently higher in wood chips than bark chips at 40°C, whereas no prepupae survived exposure to 60°C for eight or more hours. In a second study, prepupae in wood chips were exposed to 40, 45, 50, 55, or 60°C for 20 or 120 min. Some prepupae survived 20 min of exposure to all temperatures. No prepupae survived exposure to 60°C for 120 min, but 17% survived exposure to 55°C for 120 min, suggesting that some fraction of the population may survive internationally recognized phytosanitary standards (ISPM-15) for treatment of wood packing material.

Biological factors contributing to bark and ambrosia beetle species diversification

The study of species diversification can identify the processes that shape patterns of species richness across the tree of life. Here, we perform comparative analyses of species diversification using a large dataset of bark beetles. Three examined covariates—permanent inbreeding (sibling mating), fungus farming, and major host type—represent a range of factors that may be important for speciation. We studied the association of these covariates with species diversification while controlling for evolutionary lag on adaptation. All three covariates were significantly associated with diversification, but fungus farming showed conflicting patterns between different analyses. Genera that exhibited interspecific variation in host type had higher rates of species diversification, which may suggest that host switching is a driver of species diversification or that certain host types or forest compositions facilitate colonization and thus allopatric speciation. Because permanent inbreeding is thought to facilitate dispersal, the positive association between permanent inbreeding and diversification rates suggests that dispersal ability may contribute to species richness. Bark beetles are ecologically unique; however, our results indicate that their impressive species diversity is largely driven by mechanisms shown to be important for many organism groups.

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

ABSTRACT 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)

Abstract 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: Scolytus praeceps LeConte, 1868 (= Scolytus abietis Blackman, 1934; = Scolytus opacus Blackman, 1934), Scolytus reflexus Blackman, 1934 (= Scolytus virgatus Bright, 1972; = Scolytus wickhami Blackman, 1934). Two species were reinstated: Scolytus fiskei Blackman, 1934 and Scolytus silvaticus 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

Abstract 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-20th 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.

Scolytus and other Economically Important Bark and Ambrosia Beetles

Abstract The taxonomy and biology of 12 genera of economically and ecologically important scolytine bark and ambrosia beetles are described. An overview and full generic descriptions and diagnoses are given for each included genus.

Beetles (Coleoptera) of Peru: A survey of the families. Curculionidae: Scolytinae

Abstract The bark and ambrosia beetle fauna (Scolytinae) of Peru is reviewed. Examination of ∼8,000 museum and recently collected specimens and a literature review yielded 106 new country records among 248 species distributed among 56 genera and 15 tribes. Our findings for Peru increase the reported species diversity by ∼75%. Despite this thorough review, at least a hundred more Peruvian species remain to be identified or described. The geographic ranges of some species were discovered to extend more than 1,500 km from Central America or the Guyana Shield to southern Peru. It is unknown if these populations are disjunct or if they represent cryptic species. Our results suggest that only 25% of the South American scolytine fauna is known. A new synonymy of Gymnochilus glaber (Schedl, 1951) = Scolytodes schoenmanni Wood, 2007 is proposed.

Ambrosiophilus peregrinus Smith and Cognato, New Species (Coleoptera: Curculionidae: Scolytinae), an Exotic Ambrosia Beetle Discovered in Georgia, USA

Abstract A new species of exotic ambrosia beetle, Ambrosiophilus peregrinus Smith and Cognato, likely native to Asia, is described after its establishment in the United States. This species was first detected in Cherokee County, Georgia in June 2013. Since its initial discovery, the species has been found in two neighboring counties in northern Georgia. A key is presented to the species of Ambrosiophilus Hulcr and Cognato occurring in North America.

A New Species of Scolytus Geoffroy, 1762 and Taxonomic Changes Regarding Neotropical Scolytini (Coleoptera: Curculionidae: Scolytinae)

Abstract The Neotropical bark beetle genera Cnemonyx Eichhoff, 1868 and Scolytus Geoffroy, 1762 are reviewed as part of ongoing research on the higher-level taxonomy of Scolytini. Ceratolepis Chapuis, 1869, Loganius Chapuis, 1869, and Cnemonyx setulosus (Eggers, 1929) are given new status. Twenty-four new combinations are reported: Ceratolepis amazonica Eggers, 1929 (not Schedl, 1952), Ceratolepis boliviae (Blackman, 1943), Ceratolepis hylurgoides (Schedl, 1949), Ceratolepis insignis (Wood, 1969), Ceratolepis jucunda Chapuis, 1869, Ceratolepis maculicornis Blandford, 1896, Ceratolepis nigra (Eggers, 1929), Loganius confinis Wood, 1961, Loganius equihuai (Wood, 1983), Loganius euphorbiae (Wood, 1986), Loganius evidens (Wood, 1983), Loganius exilis Wood, 1967, Loganius fastigius Wood, 1961, Loganius ficus Schwarz, 1894, Loganius flavicornis Chapuis, 1869, Loganius gracilens (Wood, 1969), Loganius impressus Wood, 1961, Loganius liratus Wood, 1961, Loganius niger Wood, 1961, Loganius prociduus Wood, 1961, Loganius recavus (Wood, 1969), Loganius splendens Wood, 1961, Loganius squamifer (Wood, 1979), and Loganius vagabundus Wood, 1961. Scolytus rabaglii Smith and Cognato, new species, is described. Five new synonyms were discovered: Ceratolepis Chapuis (= Coptosomus Schedl, 1952), Cnemonyx setulosus (Eggers, 1929) (= Cnemonyx similis (Eggers, 1929)), Loganius flavicornis Chapuis, 1869 (= Cnemonyx opacus Wood, 1969), Scolytus proximus Chapuis, 1869 (= Scolytus brevicauda Wichmann, 1915), and Scolytus thoracicus Chapuis, 1869 (= Scolytus plaumanni Wood, 2007). Two new country records are reported: Scolytus multistriatus in Argentina and Brazil.

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

Abstract 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.