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Name: Abby D.
Status: N/A
Age: 16
Location: N/A
Country: N/A
Date: 2002

What chemicals in the brain are responsible for the physiological responses to attraction? For instance, what allows a female bullfrog to choose one male over another. This is related to pheromones.

Interestingly, there has been quite a bit of research on mate choice in frogs, and it does not point towards pheromones. Researchers put individual males in a soundproof room and measured their calls, in terms of the frequency and amplitude, etc. Based on this, they labelled the males as either "strong" or "weak" callers. Then they put a female in the middle of two males -- one, a strong caller, and the other, a weak caller. In the great majority of cases, the female made a beeline to the "strong-calling" male, i.e., the one that was putting more energy into his call. They concluded that females preferred the strong callers.

To test their theory, they put a female between a male frog and a speaker. When they played male calls on the speaker that were similar to "high output" calls from a real male, the female happily climbed up on the speaker and made googoo eyes at it, ignoring the real (weakly-calling) male. Not a good case for pheromones.

One interpretation of this data, favored by the authors of the study, is that all the males need energy for essential things, like eating and avoiding predators..... and only the strongest, "fittest" potential mate will have the extra energy to spare for the loudest, most boisterous calls ("gosh, he MUST have good genes to have all that spare energy for wooing me").

Cynics might conclude that the loud-calling frogs are the amphibian counterpart to the guys who drape themselves in large gold necklaces and drive expensive cars. Not to imply that the females are consciously making this decision (errr, the female frogs, that is)... :-)

Paul Mahoney, Ph.D.

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