The Essential Role of Taxonomic Expertise in the Creation of DNA Databases for the Identification and Delimitation of Southeast Asian Ambrosia Beetle Species (Curculionidae: Scolytinae: Xyleborini)

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 ~300,000 species. This promise of a universally applicable identification tool suggests that morphologically based tools and taxonomists will soon not have utility. Here we demonstrate that DNA-based identification is not reliable without the contributions of taxonomic experts. We use ambrosia beetles (Xyleborini), which are known for great diversity as well as global invasions and damage, as a test case. Recent xyleborine introductions have caused major economic and ecological losses, thus timely species identifications of new invaders are necessary. This need is hampered by a paucity of identification tools and a fauna that is only moderately documented. To help alleviate deficiencies in their identification, we created COI and CAD DNA barcode databases (490 and 429 specimens), representing over half of the known fauna of Southeast Asia (165/316 species). Taxonomic experts identified species based on original descriptions and type specimens. Tree, distance, and iterative methods were used to assess the identification and delimitation of species. High intra- and interspecific COI distances were observed for congeneric species and attributed to the beetle's inbreeding system. Neither of the two markers provided 100% identification success but with the neighbor-joining tree-based method, 80% of species were identified by both genes. As for species delimitation, an obvious barcode gap between intra- and interspecific differences was not observed. Correspondence between distance-based groups and morphology-based species was poor. In a demonstration of iterative taxonomy, we constructed parsimony-based 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 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.publishedVersio

Insect assemblages attacking seeds and fruits in a rainforest in Thailand

Insect seed predators are important agents of mortality for tropical trees, but little is known about the impact of these herbivores in rainforests. During three years at Khao Chong (KHC) in southern Thailand we reared 17,555 insects from 343.2 kg or 39,252 seeds/fruits representing 357 liana and tree species. A commented list of the 243 insect species identified is provided, with details about their host plants. We observed that: (1) about 43% of identified species can be considered pests. Most were seed eaters, particularly on dry fruits. (2) About 19% of parasitoid species (all Opiinae) for which we could determine whether their primary insect host was a pest or not (all Bactrocera spp. breeding in fruits) can be considered beneficials. (3) The seeds/fruits of about 28% of the plant species in this forest were free of attack. Phyllanthaceae, Rubiaceae, and Meliaceae were attacked relatively infrequently; in contrast, Annonaceae, Fabaceae, Sapindaceae, and Myristicaceae were more heavily attacked. There was no apparent effect of plant phylogeny on rates of attack but heavily attacked tree species had larger basal area in the KHC plot than rarely attacked tree species. (4) Insects reared from fleshy fruits were more likely to exhibit relatively stable populations compared to insects reared from dry fruits, but this was not true of insects reared from dipterocarps, which appeared to have relatively stable populations throughout the study period. We tentatively conclude that insects feeding on seeds and fruits have little effect on observed levels of host abundance in this forest

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

A review of the genus Baiocis Browne, 1962 (Coleoptera: Curculionidae: Platypodinae), with new species, new synonymy and a key to males

Beaver, Roger A. (2018): A review of the genus Baiocis Browne, 1962 (Coleoptera: Curculionidae: Platypodinae), with new species, new synonymy and a key to males. Zootaxa 4434 (3): 481-501, DOI: 10.11646/zootaxa.4434.3.

A review of the genus Carchesiopygus Schedl (Coleoptera: Curculionidae: Platypodinae), with keys to species

Beaver, Roger A., Sanguansub, Sunisa (2015): A review of the genus Carchesiopygus Schedl (Coleoptera: Curculionidae: Platypodinae), with keys to species. Zootaxa 3931 (1): 401-412, DOI: 10.11646/zootaxa.3931.3.

FIGURES 5‒8. Euwallacea insolitus holotype, 2.9 in The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae

FIGURES 5‒8. Euwallacea insolitus holotype, 2.9 mm. Dorsal, lateral, posterior oblique and anterior views.Published as part of &lt;i&gt;Beaver, Roger A. &amp; Smith, Sarah M., 2022, The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae, pp. 1-24 in Zootaxa 5174 (1)&lt;/i&gt; on page 6, DOI: 10.11646/zootaxa.5174.1.1, &lt;a href="http://zenodo.org/record/6972960"&gt;http://zenodo.org/record/6972960&lt;/a&gt

FIGURES 1‒4. Cyclorhipidion druk holotype, 3.4 in The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae

FIGURES 1‒4. Cyclorhipidion druk holotype, 3.4 mm. Dorsal, lateral, posterior oblique and anterior views.Published as part of &lt;i&gt;Beaver, Roger A. &amp; Smith, Sarah M., 2022, The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae, pp. 1-24 in Zootaxa 5174 (1)&lt;/i&gt; on page 4, DOI: 10.11646/zootaxa.5174.1.1, &lt;a href="http://zenodo.org/record/6972960"&gt;http://zenodo.org/record/6972960&lt;/a&gt

The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae

Beaver, Roger A., Smith, Sarah M. (2022): The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae. Zootaxa 5174 (1): 1-24, DOI: 10.11646/zootaxa.5174.1.

A new West African genus of Bostrichidae (Coleoptera), and a key to the Afrotropical genera of tribe Xyloperthini

A new genus, Plesioxylion Liu & Beaver gen. nov., is described for Amintinus gambianus Borowski, 2018 from West Africa with a more detailed description and new records of both sexes. We also provide a key to the ten Afrotropical genera in the tribe Xyloperthini Lesne, 1921 as the baseline information for a future study