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Sperm viability and sperm competition in insects.
1Department of Animal and Plant Sciences, University of Sheffield, S10 2TN, Sheffield, United Kingdom. f.m.hunter@sheffield.ac.uk
Current Biology : CB
|January 31, 2002
Summary
In insects, males in sperm competition scenarios (polyandrous species) show higher sperm viability than those without competition (monandrous species). This suggests sperm viability is a key adaptation for insect sperm competition.
Area of Science:
- Evolutionary Biology
- Reproductive Biology
- Insect Ecology
Background:
- Sperm quality is crucial for male reproductive success in vertebrates during sperm competition.
- The role of sperm quality in insects, despite widespread sperm competition, remains understudied.
Purpose of the Study:
- To investigate the relationship between sperm viability and the intensity of sperm competition in insects.
- To test if sperm viability, measured as live sperm proportion, correlates with sperm competition.
Main Methods:
- Comparative analysis of seven closely related insect species pairs.
- Each pair included one monandrous (no sperm competition) and one polyandrous (sperm competition) species.
- Sperm viability was assessed by measuring the proportion of live sperm in stored sperm.
Main Results:
- Polyandrous species consistently exhibited a higher proportion of live sperm compared to monandrous species.
- Significant inter- and intraspecific variation in live sperm percentage was observed.
- Sperm viability alone can influence male fertilization success.
Conclusions:
- Sperm viability is a significant factor in insect reproductive success under sperm competition.
- Higher sperm viability in polyandrous species suggests it is an adaptive trait for sperm competition.
- Findings highlight sperm viability as part of a broader suite of male adaptations to sperm competition in insects.