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Female genotypes affect sperm displacement in Drosophila
1Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Genetics
|July 3, 1998
Summary
Female fruit flies show genetic variation in sperm preference, influencing reproductive success. This study reveals females are not passive in sperm competition, impacting offspring paternity and fitness.
Area of Science:
- Evolutionary Biology
- Genetics
- Reproductive Biology
Background:
- Sperm competition is a key factor in male reproductive fitness.
- Previous research often overlooked the female's role in sperm utilization.
- Female mediation of sperm use can influence offspring paternity.
Purpose of the Study:
- To investigate female genotypic variation in last-male precedence.
- To determine if females actively influence sperm competition outcomes.
- To identify genetic factors underlying female control over sperm use.
Main Methods:
- Utilized Drosophila melanogaster with homozygous chromosomes from natural populations.
- Quantified sperm competition using two distinct male genotypes (bwD and B3-09).
- Assessed the composite sperm displacement parameter (P2') to measure competitive success.
Main Results:
- Significant heterogeneity in P2' was observed across different female lines.
- This variation persisted even after compensating for viability effects.
- Results imply the existence of polymorphic genes influencing sperm access to eggs.
Conclusions:
- Female genotypes differ in their propensity to favor last-sperm inseminated.
- Polymorphic genes in females likely play a role in mediating sperm competition.
- Female choice in sperm utilization represents a significant, previously underestimated, evolutionary factor.