Tests of multiple molecular markers for the identification of Great Spotted and Syrian Woodpeckers and their hybrids

Abstract

Great Spotted and Syrian Woodpeckers (Dendrocopos major and D. syriacus) are known to hybridize in nature; however, the extent of this phenomenon is not known due to difficulties in hybrid detection based on plumage analyses. Here, we tested five markers (one mitochondrial and four nuclear) and a set of six microsatellite loci for the identification of these two Woodpeckers and their hybrids. Sequencing of DNA from 26 individuals of both Woodpeckers from different parts of their ranges: one allopatric (D. major; Norway) and two sympatric (Poland and Bulgaria) showed that both species can be clearly separated based on all sequence markers. The highest number of fixed nucleotide sites were found in the mtDNA control region and intron 5 of the transforming growth factor. Analyses of microsatellite data distinguished the two species, but all loci showed a large number of common alleles and their utility in identifying hybrids is therefore doubtful. According to the DNA sequence analyses, 2 out of 18 specimens within the sympatric range in Poland were identified as possible hybrids, most probably paternal backcrosses. Moreover, both hybrids are from synantropic populations (settled in cities), whereas none of the D. major sampled in forests and in its allopatric range (Norway) showed signs of an intermixed genotype. Further research on hybridization and introgression in woodpeckers is undoubtedly needed and could be useful for understanding ecological and ethological interactions among these species, particularly for D. syriacus, which is relatively rare in Europe.

Hybrids and mixed pairs of Syrian and Great-spotted Woodpeckers in urban populations

“…Some differences in ethology of these species may make SW females more likely to mate with GW if there is a lack of unpaired SW males (Figarski 2017). It is also interesting that there were several examples of mixed pairs in which one bird was of hybrid phenotype, which suggests that D.syriacus × D.major offsprings should be viable (which is consistent with preliminary genetic data; Michalczuk et al 2014). Also, the even sex ratio in hybrid individuals indicates that there should not be negative effects of interspecific cross-breeding.…”

A new classification of the Pied Woodpeckers assemblage (Dendropicini, Picidae) based on a comprehensive multi-locus phylogeny

“…The two species differ by 1.2% divergence in the ATP6 locus. The possibility of hybridization among the Palearctic species appears to be relatively common as hybrids identified using molecular data have also been noticed between D. major and D. syriacus (Michalczuk et al 2014). …”

Rampant introgressive hybridization in Pogoniulus tinkerbirds (Piciformes: Lybiidae) despite millions of years of divergence

“…In songbirds, individuals in contact zones may copy the song of heterospecific males and produce mixed song, which might facilitate hybridization (Qvarnstrom et al, 2006). Hybridization is also widespread, however, in avian families without song learning, such as in ducks (Johnsgard, 1967), quails (Gee, 2003) and woodpeckers (Cicero & Johnson, 1995;Moore, 1995;Wiebe, 2000;Randler, 2002;Fuchs et al, 2013;Michalczuk et al, 2014).…”