Morphological, molecular and biological evidence reveal two cryptic species inMecinus janthinusGermar (Coleoptera, Curculionidae), a successful biological control agent of Dalmatian toadflax,Linaria dalmatica(Lamiales, Plantaginaceae)

Abstract

A combined morphological, molecular and biological study shows that the weevil species presently named Mecinus janthinus is actually composed of two different cryptic species: M. janthinus Germar, 1821 and M. janthiniformis Toševski & Caldara sp.n. These species are morphologically distinguishable from each other by a few very subtle morphological characters. On the contrary, they are more readily distinguishable by both molecular and biological characters. A molecular assessment based on the mitochondrial DNA cytochrome oxidase subunit II gene revealed fixed differences between the two species with p‐distances between samples of both species ranging from 1.3 to 2.4%. In addition to this, the larvae of the two species are found to develop on different species within the genus Linaria (Plantaginaceae): M. janthinus is associated with yellow toadflax (L. vulgaris) and M. janthiniformis with broomleaf toadflax (L. genistifolia) and Dalmatian toadflax (L. dalmatica). Molecular and host use records further suggest the occurrence of a third species associated with L. vulgaris within M. janthinus, sampled from north Switzerland, central Hungary and east Serbia. The significance of these new findings is of particular importance because species of the M. janthinus group are used, or are potential candidates, for the biological control of invasive toadflaxes in North America.

Plastid DNA Analysis Reveals Cryptic Hybridization in Invasive Dalmatian Toadflax (Linaria dalmatica) Populations

“…Mecinus janthiniformis exhibits a strong host preference for DT and does not readily establish on YT in the field. A recently confirmed cryptic congener, the YT stem-mining weevil M. janthinus, shows promise as a selective biocontrol agent for YT (Toševski et al 2011(Toševski et al , 2013. Cryptic hybridization resulting in apparent YT or DT populations containing introgressed genetic material from the other species could make such populations unacceptable as hosts for their presumed Mecinus species and may explain why at some locations of presumed DT invasion, repeated releases of M. janthiniformis, in particular, have been unsuccessful (S.E.S., personal observation).…”

“…The response of hybrid toadflax populations to herbicides has not, to our knowledge, been documented, and although the biocontrol agents Mecinus janthinus Germar and Dalmatian and Mecinus janthiniformis Toševski & Caldara are widely released on YT and DT, respectively (Toševski et al 2011), little is known about their efficacy on genetically complex (e.g., hybrid) toadflax populations. The research described…”

Obligatory duetting behaviour in theChrysoperla carnea‐group of cryptic species (Neuroptera:Chrysopidae): its role in shaping evolutionary history

“…In more recent years, cryptic species have received increasing attention, especially as DNA analyses, morphometric studies, and ecophysiological experiments have revealed hidden taxonomic diversity within species previously thought to be undifferentiated, e.g. numerous parasitoid wasps (Nagarkatti, 1975;Stouthamer et al, 2000;Triapitsyn et al, 2010) and beetles that feed on invasive plants (Davis et al, 2011;Tosevski et al, 2011). Although the cryptic species of the carnea-group are not host-specific like the examples above, it is nevertheless equally important that lacewings are correctly identified.…”

Piecing together an integrative taxonomic puzzle: microsatellite, wing shape and aedeagus length analyses of Bactrocera dorsalis s.l. (Diptera: Tephritidae) find no evidence of multiple lineages in a proposed contact zone along the Thai/Malay Peninsula

“…Few papers follow the recommended protocols for integrative taxonomy, which include stating the species definition used, developing testable hypothesis/es relevant to that definition, and then testing the hypothesis with at least three independent lines of research; only after which are interpretations of species limits made (Schlick‐Steiner et al , 2010). Some papers broadly follow this approach (Heethoff et al , 2011; Tixier et al , 2011; Tosevski et al , 2011), but they remain uncommon. Here we contribute to integrative taxonomy studies with a pair of pest Diptera which are of international importance as agricultural and quarantine pests.…”