On the systematics of the tribe Tanytarsini (Diptera: Chironomidae) – three new species from Finland

Three new chironomid species of the tribe Tanytarsini are described from Finland: Micropsectra malla sp. n., Paratanytarsus paralaccophilus sp. n. and Tanytarsus paraniger sp. n. The new species are compared with their closest relatives and their systematic position is discussed. As a result of our study, the Micropsectra recurvata species group Säwedal, 1981 is regarded as unwarranted and its species are included to the Micropsectra notescens group Säwedal, 1976. The Finnish fauna ofthe tribe Tanytarsini, consisting of 123 valid species, is one of the most species-rich in Europe

Macroinvertebrate species occupancy frequency distribution patterns in eutrophic lakes

Metacommunity models describe species occupancy frequency distribution (hereinafter 'SOFD'). Our goal is to present how the differences in eight macroinvertebrate orders dispersal ability affect SOFD patterns. A total of 293 species from eight macroinvertebrate orders were observed in 14 eutrophic lakes in southern Finland. Species occupancy ranged from 1 to 14. About 30% (89 out of 293) of the species were found in only one lake, yielding a surprisingly high number of rare species. So, there were few widely distributed common species and numerous rare species with a restricted distribution. Combined data from eight macroinvertebrate orders supported the bimodal truncated SOFD pattern. Similarly, the low dispersal ability orders, watermites and mayflies, fitted the bimodal truncated SOFD pattern. However, bimodal symmetric SOFD pattern also fitted relatively well to the dragonflies and damselflies with high dispersal ability. It seems that differences in dispersal ability among different macroinvertebrate orders may partly explain observed differences. Moreover, our results supported slightly more a niche-based model rather than a metapopulation dynamics model in eutrophic lakes littoral macroinvertebrate metacommunities. Our results highlight that the dispersal ability is important trait for species conservation in patchily distributed habitat.</p

Highly variable species distribution models in a subarctic stream metacommunity : Patterns, mechanisms and implications

Special Issue: Metacommunities in river networks: The importance of network structure and connectivity on patterns and processes1. Metacommunity theory focuses on assembly patterns in ecological communities, originally exemplified through four different, yet non-exclusive, perspectives: patch dynamics, species sorting, source-sink dynamics, and neutral theory. More recently, three exclusive components have been proposed to describe a different metacommunity framework: habitat heterogeneity, species equivalence, and dispersal. Here, we aim at evaluating the insect metacommunity of a subarctic stream network under these two different frameworks. 2. We first modelled the presence/absence of 47 stream insects in northernmost Finland, using binomial generalised linear models (GLMs). The deviance explained by pure local environmental (E), spatial (S), and climatic variables (C) was then analysed across species using beta regression. In this comparative analysis, site occupancy, as well as taxonomic and biological trait vectors obtained from principal coordinate analysis, were used as predictor variables. 3. Single-species distributions were better explained by in-stream environmental and spatial factors than by climatic forcing, but in a highly variable fashion. This variability was difficult to relate to the taxonomic relatedness among species or their biological trait similarity. Site occupancy, however, was related to model performance of the binomial GLMs based on spatial effects: as populations are likely to be better connected for common species due to their near ubiquity, spatial factors may also explain better their distributions. 4. According to the classical four-perspective framework, the observation of both environmental and spatial effects suggests a role for either mass effects or species sorting constrained by dispersal limitation, or both. Taxonomic and biological traits, including the different dispersal capability of species, were scarcely important, which undermines the patch dynamics perspective, based on differences in dispersal ability between species. The highly variable performance of models makes the reliance on an entirely neutral framework unrealistic as well. According to the three-component framework, our results suggest that the stream insect metacommunity is shaped by the effect of habitat heterogeneity (supporting both species-sorting and mass effects), rather than species equivalence or dispersal limitation. 5. While the relative importance of the source-sink dynamics perspective or the species-sorting paradigm cannot be deciphered with the data at our disposal, we can conclude that habitat heterogeneity is an important driver shaping species distributions and insect assemblages in subarctic stream metacommunities. These results exemplify that the use of the three-component metacommunity framework may be more useful than the classical four perspective paradigm in analysing metacommunities. Our findings also provide support for conservation strategies based on the preservation of heterogeneous habitats in a metacommunity context.Peer reviewe

A molecular-based identification resource for the arthropods of Finland

Publisher Copyright: © 2021 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.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.Peer reviewe

Checklist of the family Chironomidae (Diptera) of Finland

A checklist of the family Chironomidae (Diptera) recorded from Finland is presented