Vocal communication and reproductive behavior of the frog Colostethus beebei in Guyana

The endemic, dendrobatid frog, Colostethus beebei, lived and bred only in water-filled axils of a giant terrestrial bromeliad, Brocchinia micrantha, at Kaieteur National Park, Guyana, South America. Vocalizations initiate reproduction in frogs, and male C. beebei employed three types: advertisement, territorial encounter, and courtship calls. Males responded aggressively to advertisement calls from strangers played in their territories but vocalized antiphonally in response to calls from neighbors. Male C. beebei spent 40% of their time-activity budget vocalizing. Females preferred advertisement calls delivered at repetition rates above that of the population mean and from larger males. Courtship was prolonged and included close-range vocal, visual, and tactile stimulation between the sexes. Clutches of four pigmented eggs were laid on leaves above the water of bromeliad tanks. After ovipositing, females spent much time on their mates' territories. Both parents provided care-males tended clutches, moistened eggs with fluid squirted from their cloacae during low humidity times of the day, and transported tadpoles. Tadpoles occasionally fed on unfertilized eggs deposited directly in their pool by their mother. Most tadpole nutrition was obtained by grazing on algal mats and by capturing mobile prey in bromeliad pools. Although we observed con- and heterospecific cannibalism among C. beebei tadpoles, cannibalism seemed to be rare. Overall, our observations suggest that C. beebei exhibits long-term pair bonding and facultative nutritive egg provisioning. These behaviors have not yet been reported for other members of the genus Colostethus but seems essential to C. beebei's obligate life on B. micrantha with its food-limited larval microhabitats. Comparisons with other frog species that feed eggs to their progeny suggests that this strategy is an evolutionarily derived trait in C. beebei.