Pattern and process in a narrow hybrid zone

Migratory orientation in a narrow avian hybrid zone

BACKGROUND Zones of contact between closely related taxa with divergent migratory routes, termed migratory divides, have been suggested as areas where hybrid offspring may have intermediate and inferior migratory routes, resulting in low fitness of hybrids and thereby promoting speciation. In the Rocky Mountains of Canada there is a narrow hybrid zone between Audubon's and myrtle warblers that ...

Can Song Discriminate between Macgillivray's and Mourning Warblers in a Narrow Hybrid Zone?

Morphology, genetics, and ecology of pocket gophers (genus Geomys) in a narrow hybrid zone

A population of hybrid pocket gophers (Geomys bursarius x G. lutesccns) exists 1-2 km west of Oakdale, Antelope County, Nebraska, U.S.A. The hybrids occur in soil that has characteristics intermediate between that occupied by G. lutescens (sand) and by G. bursorim (silt loam); the vegetation associations on the different soils are Sandhills Prairie and Tall-grass Prairie, respectively, with mix...

Strong natural selection on juveniles maintains a narrow adult hybrid zone in a broadcast spawner.

Natural selection can maintain and help form species across different habitats, even when dispersal is high. Selection against inferior migrants (immigrant inviability) acts when locally adapted populations suffer high mortality on dispersal to unsuitable habitats. Habitat-specific populations undergoing divergent selection via immigrant inviability should thus show (1) a change in the ratio of...

Mitochondrial DNA Variation in Field Crickets across a Narrow Hybrid Zone’

We have examined mitochondrial DNA (mtDNA) restriction-site variation within and between populations of fall-adult field crickets across a narrow hybrid zone in Connecticut. Our analysis reveals two distinct mtDNA lineages, each consisting of a single common genotype together with one or more rare genotypes. Outside the hybrid zone, the association between mtDNA genotype and species designation...