|Hertach, Thomas - University Of Basel|
|Stephane, Puissant - Muséum National D’Histoire Naturelle|
|Matija, Gogala - Desiderio Finamore Veterinary Research Institute (FEPAGRO)|
|Tomi, Trilar - Desiderio Finamore Veterinary Research Institute (FEPAGRO)|
|Reto, Hagmann - University Of Basel|
|Hannes, Baur - University Of Berne|
|Gernot, Kunz - Universitat Graz|
|Simon, Loader - University Of Basel|
|Chris, Simon - University Of Connecticut|
|Peter, Nagel - University Of Basel|
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2016
Publication Date: 11/16/2016
Citation: Hertach, T., Stephane, P., Matija, G., Tomi, T., Reto, H., Hannes, B., Gernot, K., Wade, E.J., Simon, L., Chris, S., Peter, N. 2016. Complex within complex: integrative taxonomy reveals hidden diversity in Cicadetta brevipennis (Hemiptera: Cicadidae) and unexpected relationships with a song divergent relative. PLoS One. 11(11):e0165562.
Interpretive Summary: Cicadas are charismatic insects that are found throughout the world and are known for their loud male calling songs. While they are not considered to be pests or have economic significance, they are a diverse group of insects that are useful for studying evolution, behavior, acoustics, and ecology. A scientist at the USDA-ARS, in conjunction with researchers from the the US and Europe studied a European group of cicadas to determine how many species exist. Using multiple types of data, they determined that instead of one species, Cicadetta brevipennis, there are in fact two species: C. petryi and C. brevipennis, and C. brevipennis is comprised of at least three subspecies.
Technical Abstract: Multiple sources of data in combination are essential for species delimitation and classification of difficult taxonomic groups. Here we investigate a cicada taxon with unusual cryptic diversity and we attempt to resolve seemingly contradictory data sets. Cicada songs act as species-specific premating barriers and have been used extensively to reveal hidden taxonomic diversity in morphologically similar species. The Palaearctic Cicadetta montana species complex is an excellent example where distinct song patterns have disclosed multiple recently described species. Indeed, two taxa turned out to be especially diverse in that they form a “complex within the complex”: the Cicadetta cerdaniensis song group (4 species studied in a previous work) and Cicadetta brevipennis (examined in detail here). Based on a combination of acoustic, morphologic, molecular, ecological and spatial data sampled throughout their broad European distribution, we find that Cicadetta brevipennis s. l. comprises five lineages. The most distinct lineage is identified as Cicadetta petryi Schumacher, 1924, which we re-assign to the species level. Cicadetta brevipennis litoralis Puissant & Hertach ssp. n. and Cicadetta brevipennis hippolaidica Hertach ssp. n. are new to science. The latter hybridizes with Cicadetta brevipennis brevipennis Fieber, 1876 at a zone inferred from intermediate song patterns. The fifth lineage requires additional investigation. The C. cerdaniensis and the C. brevipennis song groups exhibit characteristic, clearly distinct basic song patterns that act as reproductive barriers. However, they remain completely intermixed in the Bayesian and maximum likelihood COI and COII mitochondrial DNA phylogenies. The closest relative of each of the four cerdaniensis group species is a brevipennis group taxon. In our favoured scenario, the phylogenetic pairs originated in common Pleistocene glacial refuges where the taxa speciated and experienced sporadic inter-group hybridization leading to extensive introgression and mitochondrial capture.