Meeting Abstract
Amphibians exhibit a stunning diversity of reproductive modes ranging from aquatic larvae to terrestrial, direct developing metamorphs. Marsupial frogs display one intriguing reproductive mode in which females carry eggs adhered to their dorsum until metamorphosis. In some marsupial frog species, the developing embryos are entirely enclosed in a well-vascularized, sealed dorsal brooding pouch. While anurans are generally all considered to be oviparous with lecithotrophic eggs (i.e.the embryo receives no nutrition other than yolk), the extensively vascularized membrane of the marsupial frog (Gastrotheca excubitor) brood pouch suggests that there may be opportunities for nutrient transfer. We used carbon (13C) and nitrogen (15N) stable isotopes to track nutrient allocation in gravid marsupial frogs, and to test if there is maternal nutrient transfer to developing embryos. Through feeding gravid marsupial frogs insects labeled with a 13C labeled fatty acid and a 15N labeled amino acid, we found that embryos and maternal tissues all exhibited significant increases in d13C and d15N values. These results suggest that in addition to gas exchange, the vascularized membrane of the marsupial frog brood pouch also provides a means for maternal nutrient transfer.
