DNA barcodes reveal cryptic genetic diversity within the blackfly subgenus Trichodagmia Enderlein (Diptera: Simuliidae: Simulium) and related taxa in the New World

Abstract

In this paper we investigate the utility of the COI DNA barcoding region for species identification and for revealing hidden diversity within the subgenus Trichodagmia and related taxa in the New World. In total, 24 morphospecies within the current expanded taxonomic concept of Trichodagmia were analyzed. Three species in the subgenus Aspathia and 10 species in the subgenus Simulium s.str. were also included in the analysis because of their putative phylogenetic relationship with Trichodagmia. In the Neighbour Joining analysis tree (NJ) derived from the DNA barcodes most of the specimens grouped together according to species or species groups as recognized by other morphotaxonomic studies. The interspecific genetic divergence averaged 11.2% (range 2.8–19.5%), whereas intraspecific genetic divergence within morphologically distinct species averaged 0.5% (range 0–1.2%). Higher values of genetic divergence (3.2–3.7%) in species complexes suggest the presence of cryptic diversity. The existence of well defined groups within S. piperi, S. duodenicornium, S. canadense and S. rostratum indicate the possible presence of cryptic species within these taxa. Also, the suspected presence of a sibling species in S. tarsatum and S. paynei is supported. DNA barcodes also showed that specimens from species that were taxonomically difficult to delimit such as S. hippovorum, S. rubrithorax, S. paynei, and other related taxa (S. solarii), grouped together in the NJ analysis, confirming the validity of their species status. The recovery of partial barcodes from specimens in collections was time consuming and PCR success was low from specimens more than 10 years old. However, when a sequence was obtained, it provided good resolution for species identification. Larvae preserved in ‘weak’ Carnoy’s solution (9:1 ethanol:acetic acid) provided full DNA barcodes. Adding legs directly to the PCR mix from recently collected and preserved adults was an inexpensive, fast methodology to obtain full barcodes. In summary, DNA barcoding combined with a sound morphotaxonomic framework provides an effective approach for the delineation of species and for the discovery of hidden diversity in the subgenus Trichodagmia.

An Asiatic Chironomid in Brazil: morphology, DNA barcode and bionomics

“…Similar values were observed in studies on other insects, including some Diptera families (e.g., Beckenbach and Borkent 2003; Hamada et al 2010; Hernández-Triana et al 2012). Although Silva et al (2013) attributed low intraspecific divergence (mean 0.91%) to the specimens having been collected in the same place, our results and other studies, for example, with Lepidoptera and Simuliidae, do not corroborate this hypothesis (e.g., Hebert et al 2004; Hernández-Triana et al 2012). …”

DNA barcoding of tropical black flies (Diptera: Simuliidae) of Thailand

“…Our study of Oriental morphospecies achieved levels of identification accuracy comparable with those for New World taxa (Rivera & Currie ; Hernández‐Triana et al . ), supporting the utility of DNA barcoding for identification of tropical black flies. Only 13 (3.7%) of 351 sequences were misidentified (Table ); they typically were assigned to closely related species.…”

Recovery of DNA barcodes from blackfly museum specimens (Diptera: Simuliidae) using primer sets that target a variety of sequence lengths

“…Inferred support for the NJ clustering patterns was obtained by performing a bootstrapped analysis in MEGA as detailed in Hernández‐Triana et al . ().…”

“…Most of the specimens were >10 years old (mean = 26 years; median = 28 years, mode = 28 years). In order to avoid some of the problems outlined in Hernández () with regard to using archived blackfly specimens for molecular analysis, specimens were only used when it was clear that they had been collected in accordance with the protocols outlined by R.W. Crosskey and A.J.…”

“…Crosskey and A.J. Shelley (see Hernández , ). For consistency, priority was given where possible to specimens that had been identified by L. M. Hernández‐Triana and other Simuliidae taxonomic specialists such as R.W.…”