1 The ambrosia beetle morphologically identified as Euwallacea fornicatus consists of several cryptic species that exhibit large differences in the DNA sequences of several nuclear and mitochondrial gene regions. 2 Based on these differences, we suggest that there are at least three different species each with distinct phylogeography. 3 Members of this cryptic species complex have invaded many areas outside their native range and cause substantial damage to both agriculture (avocado in particular) and other tree species. 4 Three of these cryptic species have invaded the USA: two species in California and a third species in both Florida and Hawaii. 5 Identification of their native range allows directed search for their natural enemies that may be used in biological control of these tree pests.

The ambrosia beetle Euwallacea fornicatus Eichhoff sensu lato is a complex of genetically divergent emerging pests responsible for damages to tree industries and ecosystems around the world. All lineages within the species complex are currently considered morphologically identical, presenting problems for their delineation and highlighting the shortcomings of species concepts based solely on type-specimen morphology. The objectives of this work were to 1) broaden the geographic sampling of the E. fornicatus complex in Asia, 2) reconstruct relationships between clades and populations, 3) find morphological characters or combinations of characters which are useful in delimiting the genetic lineages of the E. fornicatus species complex, and 4) propose taxonomic delimitation of species where morphology and phylogenetic identity correlate. Our integrated approach using molecular and morphological evidence suggests four clades that differ morphologically, but with overlap, therefore, cytochrome oxidase c subunit I (COI) barcoding remains necessary for assigning specimens to a clade. The following taxonomic changes are proposed: E. fornicatus (Eichhoff 1868) (= ‘Tea Shot Hole Borer Clade a’); E. fornicatior (Eggers 1923), stat. rev. (= ‘Tea Shot Hole Borer Clade b’); E. whitfordiodendrus (Schedl 1942), stat. rev. (= ‘Polyphagous Shot Hole Borer’); and E. kuroshio Gomez and Hulcr, sp. nov. (= ‘Kuroshio Shot Hole Borer’). This approach delivers a practical, evidence-based guidance for species delineation that can address overlapping variation in morphological characters of an emerging pest species complex.

DNA holds great potential for species identification and efforts to create a DNA database of all animals and plants currently contains >7.5 million sequences representing Cognato et al. Taxonomic Expertise Improves Beetle DNA-Identification species was poor. In a demonstration of iterative taxonomy, we constructed parsimonybased phylogenies using COI and CAD sequences for two genera. Although not all clades were resolved or supported, we provided better explanations for species boundaries in light of morphological and DNA sequence differences. Confident species identifications demonstrated <3% COI and <1% CAD difference and recognition of new species became more probable when there was >10-12% COI and/or >2-3% CAD. Involvement of taxonomic experts from the start of this project was essential for the creation of a stable foundation for the DNA identification of xyleborine species. In general, their role in DNA barcoding cannot be underestimated and is further discussed.

The present state of knowledge of the scolytine ambrosia beetles of Thailand is summarised to provide a basis for future studies of the fauna and its economic importance in forestry, timber production and crop tree plantations. A checklist of the fauna is provided with information on local and world distribution, host trees, biology and taxonomy. Six faunal elements based on geographical distribution, and the host tree and altitudinal preferences of species are discussed. One hundred and sixty-one species are recorded from Thailand, 67 of them for the first time. The following new synonym is proposed: Euwallacea wallacei (Blandford) (= Xyleborus barbatomorphus Schedl n.syn.). The following new combinations are given: Ambrosiophilus cristatulus (Schedl), Ambrosiophilus latisulcatus (Eggers), Beaverium dihingensis (Eggers), Beaverium lantanae (Eggers) and Immanus desectus (Eggers) are transferred from their present position in Ambrosiodmus; Ancipitis depressus (Eggers) and Ancipitis punctatissimus (Eichhoff) are transferred from Leptoxyleborus; Cyclorhipidion armipenne (Schedl), Cyclorhipidion inarmatum (Eggers), Euwallacea semiermis (Schedl), Fortiborus macropterus (Schedl), Microperus nudibrevis (Schedl) and Wallacellus minutus (Blandford) are transferred from Xyleborus.

Ten species of ambrosia beetles of the tribe Xyleborini,Amasabeesoni(Eggers, 1930),Amasaopalescens(Schedl, 1937),Amasacylindrotomica(Schedl, 1939),ArixyleborushirsutulusSchedl, 1969,Beaveriumlatus(Eggers, 1923),Cnestusprotensus(Eggers, 1930),Coptodryasquadricostata(Schedl, 1942),CryptoxyleborusconfususBrowne, 1950,Cryptoxyleboruspercuneolus(Schedl, 1951) andCyclorhipidionvigilans(Schedl, 1939), are recorded here for the first time in Thailand. Diagnostic characters, illustrations, distribution and biological data are provided for each species.Xylosandrusramulorum(Schedl, 1957),stat. res.is removed from synonymy withAmasacylindrotomicaand reinstated as a valid species.

An illustrated key to seventeen species of Bostrichidae recorded in association with rubberwood in Th ailand is provided. A checklist is given of nine species infesting rubberwood sawn timber in sawmills in southern Th ailand, with information on distribution, host trees and biology. Th ree species are recorded for the fi rst time from Th ailand: Cephalotoma tonkinea Lesne, Lyctoxylon dentatum (Pascoe), and Minthea reticulata Lesne.

Exotic diseases and pests of trees have caused continental-scale disturbances in forest ecosystems and industries, and their invasions are considered largely unpredictable. We tested the concept of pre-invasion assessment of not-yet invasive organisms, which enables empirical risk assessment of potential invasion and impact. Our example assesses fungi associated with Old World bark and ambrosia beetles and their potential to impact North American trees. We selected 55 Asian and European scolytine beetle species using host-use, economic, and regulatory criteria. We isolated 111 of their most consistent fungal associates and tested their effect on four important Southeastern American pine and oak species. Our test dataset found no highly virulent pathogens that should be classified as an imminent threat. Twenty-two fungal species were minor pathogens, which may require context-dependent response for their vectors at North American borders, while most of the tested fungi displayed no significant impact. Our results are significant in three ways: they ease the concerns over multiple overseas pests suspected of heightened potential risk; they provide basis for focus on the prevention of introduction and establishment of species that may be of consequence; and they demonstrate that pre-invasion assessment, if scaled up, can support practical risk assessment of exotic pathogens.

Species diversity and infestation densities of rubberwood (Hevea brasiliensis Müll. Arg.)-boring beetles at sawmills in southern Thailand were investigated during July 2007 and March 2008. Twenty-two species of wood-boring beetles, nine bostrichids, eight scolytines and five platypodines, were identified. The powder post beetle, Sinoxylon anale Lesne (40%), is the single dominant rubberwood pest in the studied area. Other frequently captured species are Sinoxylon unidentatum (Fabricius) (18%), Heterobostrychus aequalis (Waterhouse) (10%) and Lyctoxylon dentatum Lesne (9%). The Shannon diversity index of rubberwoodboring beetles in the eastern coastal area was significantly (p \ 0.01) greater than that in the western coastal area. The infestation density in the dry season was significantly higher than that in the wet season, but there were no significant differences between eastern and western coastal areas.