Table 1.
RI feature | C. remanei × C. latens a | C. briggsae × C. nigoni b |
---|---|---|
Extrinsic isolation (temperature-sensitivity) |
n.d. | Present |
Gametic isolation | n.d. | Strong |
F1 male inviability | Weak/Moderate | Strong |
F1 female inviability | Weak/Moderate | Strong |
F1 male sterility | ~10% or ~95% | ~100% |
F1 female sterility | ~0% | ~40% or ~60% |
F2 male inviability | Strong | n.a. c |
F2 female inviability | Strong | n.a. c |
Haldane’s rule | Sterility and inviability | Sterility and inviability |
Darwin’s corollary | Stronger RI for maternal C. remanei |
Stronger RI for maternal C. briggsae |
Heritable VRI d | Present | Present |
this study;
F2s cannot be produced owing to complete F1 male sterility;
genetic variability within species for reproductive isolation between species