Phylogeny and species limits in the Palaearctic chiffchaff Phylloscopus collybita complex: mitochondrial genetic differentiation and bioacoustic evidence*

Abstract

Nucleotide sequences of the mitochondrial cytochrome b gene (1041 bp), analysis of vocalizations and behavioural evidence from zones of contact were used to reassess the species limits and phylogenetic relationships at the species and subspecies levels in the Phylloscopus collybita complex. A new classification is proposed which recognizes four biological species. Phylloscopus brehmii (Iberia) and P. canariensis (Canary Islands) are genetically and bioacoustically highly distinct. There is no mitochondrial gene flow between them or with P. collybita. The Mountain Chiffchaff P. sindianus (with subspecies sindianus and Iorenzii) is equally distinct genetically from southwest Asian subspecies of P. collybita (caucasicus, brevirostris). The status of the Siberian form tristis, which shares potentially synapomorphic characters with the Mountain Chiffchaff (ascending song notes, grey‐brown adult plumage) but genetically closely resembles P. c. collybita and P. c. abietinus, remains uncertain. In two zones of secondary contact between taxa with “greenish” (P. collybita) and brownish plumage, hybridization is either unrecorded (caucasicus v lorenzii, Caucasus Mountains) or its extent is insufficiently known (abietinus v tristis, west of Ural Mountains). A phylogeny reconstructed from nucleotide sequences agrees with one based on song and some morphological characters in identifying P. brehmii as the oldest branch within the chiffchaff group. Of the remaining taxa, four fall into a clade with greenish plumage (P. collybita ssp.), two into one with brownish plumage (P. s. sindianus, P. s. lorenzii), while the position of P. canariensis with respect to these two clades is uncertain. Molecular and phenotypic phylogenies contradict each other regarding the affinities of P. (ssp.?) tristis.

Phylogenetic Signal in the Song of Crests and Kinglets (Aves: Regulus)

“…7). In several case studies, bioacoustic divergence was corroborated by molecular data, for example, in various Old World warblers such as Phylloscopus trochiloides (Irwin 2001;Irwin et al 2001); the P. collybita complex (Helbig et al 1996); P. bonelli (Helbig et al 1995); and in the species swarm of the golden-spectacled warbler, Seicercus burkii complex (Martens et al 1999;Alströ m and Olsson 2000;Martens and Eck 2000). However, a marked acoustic divergence among taxa does not necessarily imply equivalent genetic differentiation.…”

Range expansion and the possibility of an emerging contact zone between two subspecies of Chiffchaff Phylloscopus collybita ssp.

“…A portion of the 3% end of the cytochrome b gene of the mitochondria was amplified with the primers CytX (5%-ACCCTGAGGGCAAATATCATTC-3%) and CytY (5%-ATGATGATGAATGGGTGTTCG-3%) designed from known sequences of the two subspecies (Helbig et al 1996) to give a PCR product of a 650 nt. After cutting with the endonuclease Taq1, these fragments would enable a separation between abietinus and collybita mtDNA using agarose gel electrophoresis, as the former is expected to be cut into three fragments (500, 128 and 22 nt) and the latter into four fragments (400, 129, 100 and 21 nt).…”

“…The genetic differentiation between collybita and abietinus has earlier been estimated to be 1.0% at the mitochondrial cytochrome b gene (Helbig et al 1996). Of 26 birds sampled in Germany (within the range of collybita) and typed for mitochondrial DNA haplotype, one (3.8%) carried an abietinus mt haplotype.…”

Are Iberian ChiffchaffsPhylloscopus (collybita) brehmiilong-distance migrants? An analysis of flight-related morphology

“…The form brehmii is endemic to the Iberian Peninsula and southwestern France, and contacts with collybita in a narrow belt located at the southwestern edge of the Pyrenees (Salomon et al 1997, Balmori et al 2002. These two forms differ at the molecular level (4.6% divergence in the cytochrome b gene), and also have a different song (Helbig et al 1996). Remarkably, these differences have persisted over time despite noticeable gene flow, as shown by microsatellite analyses and direct identification of hybrids (Helbig et al 2001, Bensch et al 2002.…”

“…During the last decade, Old World leaf warblers (birds of the genus Phylloscopus) have become a model in this kind of studies. Leaf warblers include many closely related forms, some of which are considered to be species and others to be subspecies, whose ranges usually overlap in confined areas (Helbig et al 1996, Bensch et al 1999, Irwin et al 2001.…”