TheSimulium vernumgroup (Diptera: Simuliidae) in Europe: multiple character sets for assessing species status

Abstract

The value of using characters from multiple sources -chromosomes, ecology, gene sequences, and morphology -to evaluate the species status of closely related black flies is demonstrated for three European members of the Simulium vernum group: Simulium crenobium (Knoz, 1961), Simulium juxtacrenobium Bass & Brockhouse, 1990, and Simulium vernum s.s. Macquart, 1826. Simulium juxtacrenobium is a chromosomally, molecularly, and morphologically distinct species that diverged from S. crenobium and S. vernum s.s. about 2 Mya. It is specialized for intermittent streams, is univoltine, and is recorded for the first time from northern Europe, based on collections from Finland and Sweden, representing a range extension of about 1800 km. In contrast, S. crenobium, although confirmed as a distinct species, differs from S. vernum s.s. by only a few larval and chromosomal characters, and by a breeding habitat restricted to mountain spring brooks. Whereas all four character sets independently support the specific distinctness of S. juxtacrenobium and S. vernum s.s., multiple character sets are required to establish the specific validity of S. crenobium.

Population genetic structure of Simulium degrangei (Diptera: Simuliidae) from Western Carpathians

“…These values are higher than mean intraspecific divergence 0.72% found by Rivera & Currie (2009) in North American species, but within the range 0-3.84% given in the same study for within species divergence. In other congeneric blackfly species the divergence among population was found much higher, 2.8-18.5% (Ilmonen et al 2009;Rivera & Currie 2009), and even in both known and suspected species complexes the divergence values range from 4.5 to 6.5% (Rivera & Currie 2009). …”

“…and Simulium crenobium (Ilmonen et al 2009), and also partly in the S. damnosum species group and (cf. Morales-Hojas & Krueger 2009;Adler et al 2010).…”

“…Similarly, the identification of two related European species, Simulium vernum s. str. and Simulium crenobium was not possible based on a 618-bp long fragment of COI (Ilmonen et al 2009). The problem of species recognition and identification using DNA sequences has recently been reviewed by Adler et al (2010).…”

Chromosomal characteristics and evolutionary relationships of the Palearctic black fly Simulium carthusiense (Diptera: Simuliidae)

“…The Simulium vernum group provides numerous examples of the taxonomic difficulties in the family Simuliidae (Ilmonen et al, 2009). It is the second largest species group of black flies in the world, consisting of about 130 nominal species, 80% of which are represented in the Palearctic Region (Adler & Crosskey, 2014).…”

“…These giant, polytene chromosomes have revealed cryptic species, defined species limits, and resolved evolutionary relationships in the group (Brockhouse, 1985;Hunter, 1987). About 26 Palearctic species in the S. vernum group have been examined chromosomally (e.g., Chubareva & Petrova, 2008), but only about half of these have been resolved relative to an established reference map (Brockhouse, 1985;Hunter, 1987;Bass & Brockhouse, 1990;Adler et al, 2004;Ilmonen et al, 2009).…”