Mother Knows Best … For Frogs That Is

The Strawberry Poison Dart Frog is found in the region of Panama called Bocas Del Toro. Due to the formation of islands on the archipelago from a rise in water level over millions of years, Strawberry Poison Dart Frogs have been isolated on separate islands in the archipelago. The color of the frogs vary from island to island but are common in orange, red, green and blue. The color of these frogs was previously thought to let predators know it was poisonous with their bright colors. Now, scientists are wondering if the coloring of the frogs has any other function for the frogs.

Corinne Richards-Zawacki, Professor at the University of Pittsburgh, began to question if skin color was to alert predators about the frogs poison, “But predators don’t seem to care what color the frogs are, at least based on our earlier experiments” (Smithsonian Tropical Research Institute 1).  This lead to her and her team set up experiments to test the effect of parent frog colors on the mate and enemies of baby frogs. In the first situation there was a baby frog raised with two parents of the same color. The second situation was a baby frog raised by parents which are two different colors. The third situation was a baby frog raised by foster parents of a different color than the baby. After the baby frogs were fully grown they tested to see which color females would seek out for mates. Simultaneously they tested which color the male frogs would determine to be their rival.

The results of the experiments shows that parents have a significant effect on the mates of the baby frog. In each of the three experiments, the female frogs choose mates the same color of the parents, even if the parents were a different color than the baby frog. This was similar to the finding of the test on enemies of the male frogs. Male frogs were more aggressive towards other male frogs which were the same color of their parents, no matter if the parents were biological or foster. However, when the parents were two separate colors, females would mate with frogs the color of the mother. Males with parents of two different colors would select enemies that were the same color as the mother.

Young frogs have very imprintable minds and those first interactions with adult frogs greatly affect the lifestyle of the frog. These results show that the mother has the more important role out of the parents on the baby frogs imprinting. Colors of parents, primarily the mother, determines the color of frog the female frog mates with and also determines the color of frog the male frogs are aggressive towards.

The imprinting that adults have on the baby frogs limits the possible evolution of the Strawberry Poison Dart Frogs. The frogs are no longer reliant on natural selection from having to select the colors predators less likely attack. Professor Corinne determined that predators do not select prey based on the color of the frogs. The frogs are instead keeping to colors of their parents when they find mates to reproduce, which leads to more and more similar colored frogs in the gene pool and not many different combinations of mates.

About Mr. Mohn

Biology Teacher

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