牽牛花果蠅(Drosophila elegans)分布於東南亞的熱帶及亞熱帶區域，同地區的牽牛花果蠅呈現不同體色，大部分地區的牽牛花果蠅為棕色型，在台灣及沖繩地區為黑色型。果蠅雄蟲的前翅端區具有黑色翅斑，被認為與求偶成功率與否有關，而催化果蠅體內的多巴胺為黑色素的Yellow蛋白質，則在果蠅的體色與翅斑的形成扮演著重要的角色。本研究使用yellow基因突變的牽牛花果蠅測試體色與翅斑對雄果蠅求偶成功與否的影響，首先使用yellow突變和野生型雄果蠅與野生雌果蠅進行多重選擇測試。實驗結果顯示，yellow突變的雄果蠅交配率明顯地較野生型雄果蠅低。接下來使用了視力受損的白眼突變雌果蠅，做同樣的多重選擇測試，實驗結果與野生型雌果蠅的測試相同，暗示雌果蠅可能不是以體色選擇交配對象，在無選擇測試中，發現yellow突變的雄果蠅在求偶積極度上明顯低於野生型雄果蠅。令人感到意外地，混養兩種體色的雄果蠅後做多重選擇測試，發現雌果蠅對於不同體色的雄果蠅失去了選擇性，暗示著影響雌果蠅較不接受帶yellow突變雄果蠅的主要原因可能是雄果蠅體表碳氫化合物因為yellow基因缺陷而有所改變。;Drosophila elegans distributing in Southeast Asia exhibits two body color morphs with non-overlapping geographical distribution. The brown morph populations are found in south species range while the black morph populations are only found in Taiwan and Okinawa. Drosophila elegans possess a black wing spot at the apical region of each wing. The wing spots have been shown to associate with courtship success. Among genes involved in pigmentation, yellow gene encodes an enzyme which catalyzes dopamine to black melanin. In this study, the relationship of body color and wing spots on courtship success was tested by using a yellow mutant strain and a wildtype HK strain. We performed multiple choice tests to examine the preference on body color and wing spot by wildtype females. The less mating success rate was found in yellow mutant males. We further tested the role of body color by using white-eyed females in the multiple choice tests. The white-eyed females showed the same mating preference as that of wildtype females, suggesting that the visual perception is not the main factor affecting female preference. The frequency of courtship tested in no choice tests is lower in yellow mutant males, suggesting the male mating propensity may be reduced in yellow mutant males. Interestingly, the female preference disappeared after the yellow mutant males were mix-reared with wildtype males, suggesting the female mating preference may attribute to the change of the cuticular hydrocarbon in yellow mutant males.
