雄性黑眶蟾蜍春季的合唱鳴聲對於生精作用的強化現象

Enhancement of Spermatogenesis from Spring Male Chorus for the Spectacled Toad Duttaphrynus melanostictus (Schneider, 1799)

於春季初期，我們使用剛出現的20隻黑眶蟾蜍進行爲期33天的雄蟾蜍鳴聲刺激實驗。雄蟾蜍在每天接受鳴聲刺激的實驗組（10隻）中，其平均的精子束數目比沒有接受鳴聲刺激的實驗組（10隻），其精子束數目多出了56%。除外，在鳴聲刺激與否的實驗後，於食物的取食量及身體條件狀況（如體長、體重、肝臟重及脂肪體重等）方面，實驗組與控制組間則無統計上的差異。兩棲類雄性的合唱鳴聲不只是吸引雄性與雌性聚集的訊號，或做爲雄性間彼此競爭領域的警告之用，春季雄蟾蜍合唱鳴聲對於同種雄蟾蜍的聽覺刺激，也有強化其生精作用並加速精子的生成，以利後續生殖成功的作用。

The conspecific male chorus stimulation experiment was conducted for 33 days in the early breeding season in spring for the spectacled toad Duttaphrynus melanostictus, using 20 wild males captured shortly after their emergence from winter hibernation. The average number of sperm bundles of the test group (n=10) that received daily stimulation of male chorus was 56% higher than that of the control group (n=10) that did not have the chorus stimulation. Otherwise, there was no significant difference in food intakes, body condition (body lengths, and body, liver and fat body weights), and testicular size between the two groups after the experiment. The male chorus is not merely a vocal signal for attracting males and females for congregation, or a vocal warning in male-male competition and for territorial protection, but is also an acoustic stimulus that enhances spermatogenic activities to accelerate the sperm production for the reproductive success.