A comprehensive phylogeography of the Hyles euphorbiae complex (Lepidoptera: Sphingidae) indicates a ‘glacial refuge belt’

Abstract

We test the morphology based hypothesis that the Western Palaearctic spurge hawkmoths represent two species, the Eurasian H. euphorbiae and Afro-Macaronesian H. tithymali. It has been suggested that these species merged into several hybrid swarm populations, although a mitochondrial phylogeography revealed substructure with local differentiation. We analysed a three-gene mt-dataset (889 individuals) and 12 microsatellite loci (892 individuals). Microsatellite analyses revealed an overall weak differentiation and corroborated the superordinate division into two clusters. The data indicate that the populations studied belong to only one species according to the biological species concept, refuting the opening hypothesis. A future taxonomic revision appears necessary to reflect the division into two subgroups. Ancestral mitochondrial polymorphisms are retained in H. euphorbiae, indicating gene flow within a broad ‘glacial refuge belt’ and ongoing postglacial gene flow. Diverse patterns of extensive mito-nuclear discordance in the Mediterranean and the Middle East presumably evolved by more recent processes. This discordance indicates introgression of H. tithymali-related mitochondrial haplogroups, accompanied (to a lesser degree) by nuclear alleles, into Italian and Aegean H. euphorbiae populations as recently as the late Holocene. The complex mosaic of divergence and reintegration is assumed to have been influenced by locally differing environmental barriers to gene flow.

Museum archives revisited: Central Asiatic hawkmoths reveal exceptionally high late Pliocene species diversification (Lepidoptera, Sphingidae)

“…S2), corroborating the ambiguity surrounding species boundaries in this group found by Mende et al . (). This observation may simply be due to the extremely young age of this group (1.1 Ma, 95% HPD 1.53–0.69 Ma; Fig.…”

Pleistocene extinctions as drivers of biogeographical patterns on the easternmost Canary Islands

“…(), (3) Percy and Cronk (), (4) Percy et al. (); (5) Hundsdoerfer and Wink (), (6) Mende, Bartel, and Hundsdoerfer (), (7) Sun et al. (), (8) Emerson et al.…”

Functional characterization of the Hyles euphorbiae hawkmoth transcriptome reveals strong expression of phorbol ester detoxification and seasonal cold hardiness genes

“…We predict that candidate biomarkers identified likely contribute to a deeper understanding of mechanistic traits and shed some light on the complex species delineation and ecological adaptation within the HEC [ 6 , 8 , 9 ]. For example, it would be interesting to compare gene expression of H. euphorbiae to its Southern European relative H. tithymali which is more susceptible to TPA and cold [ 1 , 12 , 21 ] and shows introgression with H. euphorbiae at the species boundaries [ 9 , 11 ]. Similar studies have revealed profound differences between closely related Lepidoptera lineages under different environmental conditions [ 39 , 40 ].…”

“…However, geographic occurrence is neither discrete nor stable in time, denoting a scenario of ongoing hybridization and/or incomplete lineage sorting [ 8 , 9 ]. A recent study reveals that the HEC may rather be a single, genetically distinct biological species that has two morphologically and ecologically distinct subgroups [ 11 ], while discrepancies between taxon distribution ranges, morphotypes [ 7 , 12 ] and mitochondrial lineages [ 8 ] remain. The HEC primary Central European species, H. euphorbiae , is characterized by two particularly interesting ecological adaptations: The detoxification of diterpen-ester containing food plants and the survival of harsh winters.…”