Reproductive isolation and the expansion of an invasive hybrid swarm

Biological Invasions
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Abstract

Biological invasions involving hybridization proceed according to prezygotic and postzygotic reproductive isolating mechanisms. Yet few comparisons of reproductive isolation have been carried out to understand how different mechanisms prevent or promote invasions involving hybridization. Here we present a study of prezygotic and postzygotic isolation between non-native red shiner (Cyprinella lutrensis) and native blacktail shiner (C. venusta stigmatura) from the Coosa River basin (USA) to better understand the formation and expansion of invasive hybrid swarms. We conducted spawning trials to measure mating preferences and raised broods from crosses to assay hybrid viability through early juvenile development. Females of both species were more responsive to conspecific mates, although blacktail shiner females responded more often to heterospecific mates than did red shiner females. Fecundity of red shiner females was also higher than blacktail shiner females. Heterospecific crosses resulted in lower fertilization and egg hatching rates, but we found no other evidence of inviability. Rather, we found comparatively low larval mortality of F1 hybrids, which is suggestive of heterosis. These findings support prior inferences of assortative mating from genetic descriptions of hybridization, and that the invasion in the Coosa River is likely proceeding due to interspecific competition and intrinsic hybrid viability.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Reproductive isolation and the expansion of an invasive hybrid swarm
Series title Biological Invasions
DOI 10.1007/s10530-010-9688-9
Volume 12
Issue 8
Year Published 2010
Language English
Publisher Kluwer Academic Publishers
Publisher location Dordrecht
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Biological Invasions
First page 2825
Last page 2836