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Sex allocation: size matters for red spider mites
Duncan E Jackson1, Stephen J Martin
1Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK. drdejackson@yahoo.co.uk
Current Biology : CB
|December 22, 2010
Summary
Spider mites control offspring sex by egg size. Larger eggs become females, while smaller eggs develop into males, reflecting parental investment strategies.
Area of Science:
- Reproductive biology
- Animal behavior
- Genetics
Background:
- Parental investment theory suggests animals adjust offspring traits based on resource availability.
- Sex determination mechanisms vary widely across species, influencing population dynamics.
Purpose of the Study:
- To investigate the relationship between egg size and offspring sex in spider mites.
- To understand the parental investment strategies employed by spider mites in sex ratio determination.
Main Methods:
- Observation of egg-laying and offspring development in spider mites.
- Analysis of egg size variation and corresponding offspring sex.
Main Results:
- Larger eggs are consistently fertilized and develop into diploid females.
- Smaller eggs develop into haploid males.
- Egg size serves as a direct indicator of offspring sex in this species.
Conclusions:
- Spider mites exhibit a clear strategy of facultative sex determination based on egg provisioning.
- This mechanism allows parents to adjust the sex ratio of their offspring in response to their investment capacity.
