Population differentiation in the beetle Tribolium castaneum. II. Haldane's rule and incipient speciation

Haldane's rule (HR) and incipient speciation is studied in the beetle Tribolium castaneum. The results show that incipient speciation in flour beetles can occur with or without HR and that significant hybrid incompatibilities result from the accumulation of gene difference between populations without differentially affecting the heterogametic sex.