Morphological identification and COI barcodes of adult flies help determine species identities of chironomid larvae (Diptera, Chironomidae)

Abstract

Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or 'species group' level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor-joining analysis reported here describes the application and confirmation of a useful tool that can accelerate identification and bioassessment of chironomid communities.

Molecular diet studies of water mites reveal prey biodiversity

“…As stated in Pozojevic, Jursic [34], molecular studies would increase our understanding of water mite food web functional contributions such as the presence of Oligochaetes in water mite diet which was not reported in the Pozojevic, Jursic [34] study. The results seen here helps us understand some of the ecological significance of the high biodiversity of chironomids revealed in previous studies of the region [36]. For example, our barcode study of chironomids in Maumee Bay and Maumee River (Toledo, OH) revealed up to 45 chironomid operational taxonomic units [36], many of which are similar or identical to those we found with NGS in water mite diets.…”

“…The results seen here helps us understand some of the ecological significance of the high biodiversity of chironomids revealed in previous studies of the region [36]. For example, our barcode study of chironomids in Maumee Bay and Maumee River (Toledo, OH) revealed up to 45 chironomid operational taxonomic units [36], many of which are similar or identical to those we found with NGS in water mite diets. Our laboratory continues to expand this list of chironomid species in the Great Lakes region (unpublished work), identifying many new barcodes that may be represented in water mite diets.…”

Improved protocols to accelerate the assembly of DNA barcode reference libraries for freshwater zooplankton

“…Although the insect fauna of Canada has been heavily surveyed using DNA barcodes (i.e., Steinke, Breton, Berzitis, & Hebert, ), the DNA barcode‐based identification of chironomids, especially larvae, remains extremely difficult and in progress in the Great Lakes (e.g., Failla, Vasquez, Hudson, Fujimoto, & Ram, ). Because of this, only eight of the 35 BINs detected from 79 specimens could be identified to the species level.…”

Congruence between molecular and morphological systematics of Alpine non‐biting midges (Chironomidae, Diamesinae)

“…DNA barcoding studies) were successfully adopted to delimit species of chironomids (e.g. Allegrucci et al., 2012; Al‐Shami et al., 2009; Carew & Hoffmann, 2015; Ekrem et al., 2010; Ekrem et al., 2010; Failla et al., 2016) and also provided species identification of Diamesa species (Montagna et al., 2016) even if with some concerns.…”