2009年7月2日 星期四

雄蛾會對親戚減少精子的投資

photo by Patrick C..
Male moths reduce sperm investment in relatives

Zenobia Lewis1, a and Nina WedellCorresponding Author Contact Information, a, E-mail The Corresponding Author

aSchool of Biosciences, University of Exeter, Cornwall Campus, U.K.

Animal Behaviour
Volume 77, Issue 6
, June 2009, Pages 1547-1550

產生精子需付出代價、而雄性經常藉由調整射精以最大化他們的生殖成功率。先前研究顯示雄性對於雌性品質的變異是敏感的,為了精子競爭的風險與活力,雄性會依據情形調節其射精量。許多物種的雌性和雄性之間對交配對象與自己的親戚關係是敏感的,且或許會完全放棄與血緣關係相近個體交配已避免付出近親雜交的代價。此外,在一妻多夫關係下的物種,雌性具有運用交配後的機制以避免使用到雄性親戚的精子;然而,目前並未有研究顯示雄性也可以在生殖細胞的層次上分辨並避免雌性親戚。作者在此以印度穀螟蛾(Plodia interpunctella)為對象的研究中發現,與提供精子給雄性的姊妹相比,雄性提供較多可孕與不可孕的精子給無血緣關係的雌性。這些結果指出雄蛾可藉由針對交配對象的血緣關係管理其有限的精子,以減少發生在近親雜交上的生殖投資。

Sperm production carries costs and males frequently tailor their ejaculates to maximize their reproductive success. Previous work shows that males are sensitive to variation in female quality, and to the risk and intensity of sperm competition, and adjust their ejaculates accordingly. Males and females of many species are sensitive to the relatedness of their mating partners and may forego mating with related individuals altogether to avoid the costs of inbreeding. In addition, in polyandrous species, females can potentially invoke postcopulatory mechanisms to avoid using related males' sperm, but to date no study has demonstrated that males also discriminate against related females at the level of the gamete. In this study on the Indian meal moth, Plodia interpunctella, males provided unrelated females with more fertile and nonfertile sperm than their sisters. These results indicate that male moths can minimize the potential costs of inbreeding by carefully managing their limited sperm supplies in relation to partner relatedness.


Keywords: inbreeding; Indian meal moth; Plodia interpunctella; sexual selection; sperm; strategic sperm allocation

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