Date of Award


Document Type


Degree Name

Master of Science




The eggs of Rana pipiens, the southern leopard frog, were offered in several forms to Lepomis macro­ chirus, the bluegill. The fish were offered random trial discrimination tests while in groups of one or five in 40 1 aquaria. L. macrochirus learned to make distinct discriminations and rejected fertilized and unfertilized egg masses, boiled egg masses, dried frog eggs and gelatin made with homogenated frog eggs. In contrast, Shrimp-el-etts, Shrimp-el-etts dyed black, gelatin made with peptone, and ovarian eggs were accept­ ed readily. The results suggest a protective function for the gelatinous coat: both physical and chemical . The chemical is evidently added in the oviduct with the gelatinous coat, and is not affected by fertilization, desiccation or temperatures up to 100 C. Comparisons of these experiments with other studies suggest that the gelatinous coat is even more effective in discouraging predation by vertebrates in the field than in the laboratory.

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