The evidence suggests that warblers use their extremely elaborate songs primarily to attract females, clearly confirming the effectof intersexual selection on the evolution of birdsong.
证据表明，莺主要用它们极其精致的歌声吸引雌性，这清楚地证实了雌雄间选择对鸟类鸣叫进化的影响。
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"[one] effectof lower testosterone levels is loss of muscle mass and increases in fat mass," Prof Bribiescas writes in his book How Men Age: What Evolution Reveals About Male Health and Mortality.