| When two similar species co-occur in time and space, strong mechanisms isolating them from each other are expected. Acanthoscurria suina Pocock, 1903 and Eupalaestrus weijenberghi (Thorell, 1894) are two sympatric and synchronic tarantulas that inhabit burrows in Uruguay's meadows. Here we test how and when reproductive isolation operates between these species. We exposed females of each species simultaneously to two males: either one male of each species, or two males of the same species. Males courted females of both species. Contrary to expectations, however, females of A. suina responded more effusively to heterospecific than to conspecific males, whereas females of E. weijenberghi only responded to conspecific males. Clasping (prelude of mating) was... |
