Author: GRABOVSKY, VI
Abstract: The simulative models of the secondary contact zones of ecologically equivalent forms (MODEL 1) and ecologically segregated forms (MODEL 2) are proposed. <> individuals in the models are characterized by the hybrid index: from -5 for the form A and +5 for the form B. Hybrids have the intermediate score of the hybrid index: -5 to +5, and it indicates the share of genes of the parental forms in the hybrid's genotype. It was shown that A) without hybridization (absolute assertiveness) narrow para---rtry zone formed during the few first generations in MODEL 1. B) The width of the hybrid zone without assortive mating and under equal vitality of hybrids and clear individuals in MODEL 2 is only 1.5 times bigger than in MODEL 1. C). Depression of hybrids vitality effectively blocked the gene flow between the forms and reduced the hybrid zone width in both models, D) Assertiveness of mating had no influence on hybrid zone width in MODEL 1 and lead to the increase of gene now and hybrid zone width in MODEL 2. In the latter case under a high level of assertiveness of mating, the broad sympatry zone, with places of local hybridization are formed. So, 1) increasing assertiveness of mating cannot be the mechanism of improving the reproductive barriers; 2) ecologically segregated forms with assortive mating and without depression of hybrid validity have the maximum risk of losing their taxonomic individuality, Some secondary contact zones in birds. are discussed.
Source: ZHURNAL OBSHCHEI BIOLOGII
Publication Year: 1995
Volume: 56
Issue nr: 3
Pages: 291 - 309