In the E. rubivora complex, ddRAD data resolved all four species, contrary to morphological and COI data, which supports a potential scenario of host plant-driven speciation where the host plant specialization provides an ecological barrier to hybridization.
To further our understanding of the relationships between populations, both the Alpine and the extra Alpine ones, we sequenced 1,496 bp of the COI gene in 16 Alpine and Jurassian populations and analysed them in combination with published Pyrenean and Carpathian sequences.
Dating analyses indicate a mid-Cretaceous (105.3 Ma) origin of the family, followed by a rapid diversification into the nine subfamilies predating the Cretaceous–Palaeogene extinction. We hypothesize that advanced larval behaviours, such as making keeled or tentiform blotch mines, rolling leaves and galling, allowed gracillariids to better avoid larval parasitoids allowing them to further diversify.
All three species show pronounced evidence of isolation and, in two cases, secondary reconnection. An unexpected monophyletic mtDNA lineage was found in the Central Coast region, in a region thought to represent an intergrade between C. mendocino and C. walterorum.. Our results add to a currently under-appreciated pattern suggesting that coastal Central California is not a transition zone between Northern and Southern California Floristic Province faunas but rather its own unique, periodically isolated, biogeographic region.
Here we explore the use of DNA barcodes as a tool for identification and species discovery in European gracillariids. We present a barcode library including 6,791 COI sequences representing 242 of the 263 (92%) resident species.
Where previous studies showed limited success in using COI to identify Dacini, our results with a highly curated morphological dataset indicate high congruence between morphology and COI: 90% of the species in our 5,576 sequences, 262-species global dataset can be identified with COI alone based on a monophyly criterion.