Abstract. Behavioral isolation may play an important role in speciation. However, the roles of divergence time and ecological specialization on the evolution of intrinsic barriers to gene flow are poorly understood. On the Galápagos, ecotypic differentiation of Hogna Simon 1885 wolf spiders has led to the repeated evolution of morphologically distinct high-elevation and coastal species on Santa Cruz and San Cristo´ bal. This offers a unique opportunity to investigate the importance of ecological factors and evolutionary history on courtship behavior, but also to explore the opportunity for interspecific gene flow. On San Cristo´ bal, both high elevation and coastal Hogna species clearly showed distinct courtship behavior. This pattern corresponded primarily with variation in male genital organs rather than with ecotypic classification or phylogenetic relationship. Despite low acceptance rates, heterospecific mating was observed, suggesting that potential gene flow within as well as among islands should not be neglected when seeking to understand island radiations.

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