Research Training Program

Andrew Furness
Marquette University
Milwaukee, Wisconsin

Roy McDiarmid, Ph.D.
Ron Heyer, Ph.D.
George Zug, Ph.D.
Supervising Scientists
Department of Vertebrate Zoology,
Amphibians and Reptiles

"The Research Training Program has encompassed so much. In addition to the research project, I got to see incredible artifacts and hear from the passionate researches who study them, not to mention the friendships that were made."

Shedding Light on Foam Nesting Frogs

Frogs have a remarkably diverse range of reproductive behaviors and methods. One way in which frogs reproduce is by depositing fertilized eggs into a foam nest. The foam nest is generated by a secretion from the female frog which is subsequently beaten into a frothy mass using rhythmic leg or arm movements. This behavior allows for a more terrestrial mode of reproduction and has evolved independently in a number of different genera. The genus Leptodactylus of South America is one such group of frogs that builds foam nests. It has been observed that frogs that produce foam nests have a highly enlarged region of the oviduct (the tube-like structure by which eggs are transported from the ovary to the outside of the body), formerly called a 'foam gland.' The 'foam gland' presumably produces the secretion that is beaten into a foam nest. Relatively little is known about the 'foam gland.' This project sought to describe and characterize this unique structure and its distribution among different foam nesting species of frogs. The external appearance of the oviduct was described, certain characters were measured, and sections of the oviduct were prepared so that cell type and composition could be examined under a microscope. Of the foam nesting species that were examined, all showed, to varying degrees, the characteristic enlargement of the oviducts. The results of this study indicate that the foam nesting frogs of the genus Leptodactylus show a physical modification in their reproductive tract which directly corresponds to their fascinating reproductive behavior.

This research was supported by a grant from the NMNH Office of the Director.

Letter of gratitude Letter to The Honorable Max Berry