A molecular-based identification resource for the arthropods of Finland.

To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this study, we (1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), (2) publish this library, and (3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi) at https://laji.fi/en/theme/protax. Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society.

Absence of Francisella tularensis in Finnish Ixodes ricinus and Ixodes persulcatus ticks.

Francisella tularensis subsp. holarctica is the causative agent of tularaemia in Europe. Finland is a high-incidence region for tularaemia, with mosquito bites as the most common sources of infection. However, in Central and Western Europe, ticks (Acari: Ixodidae) have been suggested as the main vectors. Indeed, several studies have reported the pathogen from the locally most common human-biting tick species, Ixodes ricinus. In Finland, the occurrence of the pathogen in ticks has started receiving attention only recently. Here, we collate previous tick screening data from Finland regarding F. tularensis as well as present the results from a novel screening of roughly 15 000 I. ricinus and I. persulcatus collected from across the country. In total, 14 878 ticks collected between 2015 and 2020 were screened for F. tularensis using a TaqMan-based qPCR assay targeting the 23 KDa gene. The combined screening efforts of the current and previous studies, encompassing roughly 20 000 ticks, did not find any positive ticks. Given the negative results despite the considerable sample size, it appears that the pathogen is not circulating in local tick populations in Finland. We discuss some possible reasons for the lack of the bacterium in ticks in this high-incidence region of tularaemia.