Abstract
Although much is known about the reproductive biology of pond-breeding frogs, there is comparatively little information about terrestrial-breeding anurans, a highly successful and diverse group. This study investigates the activation and
in vitro
fertilization of eggs of the Puerto Rican coqui frog obtained by hormonally induced ovulation. We report that spontaneous activation occurs in 34% of eggs, probably in response to mechanical stress during oviposition. Artificial activation, as evidenced by the slow block to polyspermy and the onset of zygote division, was elicited both by mechanical stimulation and calcium ionophore exposure in 64% and 83% of the cases, respectively. Finally, one
in vitro
fertilization protocol showed a 27% success rate, despite the fact that about one third of all unfertilized eggs obtained by hormone injection auto-activate. We expect these findings to aid in the conservation effort of
Eleutherodactylus
frogs, the largest vertebrate genus.