Final answer:
The study showing that offspring of male tree frogs with long calls feed more and grow faster supports the good genes hypothesis. This hypothesis suggests that females choose mates with impressive traits that are indicative of genetic fitness resulting in healthier offspring with better survival traits.
Step-by-step explanation:
Direct answer in two lines: The finding supports the good genes hypothesis, suggesting that the impressive trait of long calls in male tree frogs indicates genetic superiority, leading to healthier offspring. The good genes hypothesis posits that certain traits in males, such as long calls in tree frogs, serve as honest signals of genetic fitness. When female tree frogs select mates based on these traits, they are actually choosing genetically superior partners, according to the hypothesis. Consequently, the offspring of these selected males tend to have better survival characteristics, such as spending more time feeding and growing faster.
This adheres to the idea that females may benefit from being selective even at the cost of producing fewer offspring, as long as those offspring have a higher chance of survival. The relationship between long calls and offspring vigor suggests that these calls are not just for show but represent underlying genetic qualities that are advantageous for survival and reproduction. These findings align with the theory that elaborate male displays can reflect good genes, which females preferentially choose to enhance the fitness of their own progeny.