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Phenotypic engineering unveils the function of genital morphology
Cosima Hotzy1, Michal Polak, Johanna L Rönn
1Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden.
Current Biology : CB
|October 30, 2012
Summary
Male genital spines influence fertilization success in insects. Longer spines increase fertilization rates and seminal fluid transfer, supporting sexual selection on genital morphology.
Area of Science:
- Evolutionary Biology
- Animal Behavior
- Reproductive Biology
Background:
- Male genital morphology in internally fertilizing animals is diverse and complex.
- Postcopulatory sexual selection is a proposed driver of this diversity, but direct evidence is limited.
Purpose of the Study:
- To experimentally investigate the role of male genital morphology in postcopulatory sexual selection.
- To determine if genital morphology influences fertilization success and ejaculate fate.
Main Methods:
- Used an insect model system with artificial selection and microscale laser surgery to manipulate male genital morphology.
- Assessed competitive fertilization success and used radioisotopic labeling to track ejaculate fate in females.
Main Results:
- Males with experimentally elongated genital spines achieved higher fertilization success.
- A greater proportion of ejaculate transferred into the female body with males possessing longer spines.
Conclusions:
- Male genital morphology, specifically spine length, directly impacts competitive fertilization success.
- Sexual selection on genital morphology may involve the rate of seminal fluid transfer into the female.
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