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Intrinsic reproductive isolation between Trinidadian populations of the guppy, Poecilia reticulata
Author(s) -
RUSSELL S. T.,
MAGURRAN A. E.
Publication year - 2006
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2005.01069.x
Subject(s) - biology , poecilia , reproductive isolation , guppy , sterility , gene flow , population , zoology , ecology , brood , genetic algorithm , ecological speciation , range (aeronautics) , evolutionary biology , genetics , genetic variation , demography , fishery , gene , materials science , sociology , fish <actinopterygii> , composite material
Although Trinidadian populations of the guppy, Poecilia reticulata , show considerable adaptive genetic differentiation, they have been assumed to show little or no reproductive isolation. We tested this assumption by crossing Caroni (Tacarigua River) and Oropuche (Oropuche R.) drainage populations from Trinidad's Northern Range, and by examining multiple aspects of reproductive compatibility in the F 1 , F 2 and BC 1 generations. In open‐aquarium experiments, F 1 males performed fewer numbers of mating behaviours relative to parental population controls. This is the first documentation of hybrid behavioural sterility within a species, and it suggests that such sterility may feasibly be involved in causing speciation. The crosses also uncovered hybrid breakdown for embryo viability, brood size and sperm counts. In contrast, no reductions in female fertility were detected, indicating that guppies obey Haldane's rule for sterility. Intrinsic isolation currently presents a much stronger obstacle to gene flow than behavioural isolation, and our results indicate that Trinidadian populations constitute a useful model for investigating incipient speciation.