Ecological and genetic characteristics of «yellow» wagtail hybrids

The paper examines ecological and genetic characteristics of hybrids of «yellow» wagtails: yellow white-eared wagtail Motacilla flava beema and yellow-fronted wagtail Motacilla lutea . At present, in the zone of contact between closely related forms of «yellow» wagtails, a system of their spatial and reproductive interaction with each other has been formed under conditions of wide sympatry. This interaction is manifested in the existence and maintenance in the population samples of three components of their genetic system: the genotypes M. flava , M. lutea , and the light-headed hybrid form M. f. beema × M. lutea . The new data obtained significantly supplement the understanding of the intraspecific interaction of three forms: M. flava , M. lutea , and the light-headed hybrid form M. f. beema × M. lutea . Light-headed hybrids M. f. beema × M. lutea have their own specific stable characters at different levels: morphological, behavioral, and molecular genetic as confirmation of the genetic interaction existing in natural populations between the two species, which is an interspecies mechanism for maintaining their structure. In the zone of contact between M. flava and M. lutea , unlimited hybridization of these species occurs and mixed pairs are formed. In this case, the isolation of light-headed hybrid forms with a characteristic manifestation of various groups of characters: morphological – the color of the plumage of the head; genetic – distinguishing light-headed hybrids from the original species ( M. flava and M. lutea ). This phenomenon can act as a mechanism for maintaining the integrity of the species of «yellow» wagtails – both the yellow wagtail M. flava and the yellow-fronted wagtail M. lutea due to the constantly occurring interspecific hybridization in areas of wide sympatry within a single polytypic complex.