Irregular brood patterns and worker reproduction in social wasps
Jennifer L Kovacs1, Michael A D Goodisman
1Georgia Institute of Technology, School of Biology, 310 Ferst Drive, Atlanta, GA 30332, USA.
Die Naturwissenschaften
|July 27, 2007
Summary
In social wasps, worker policing is thought to prevent reproduction in queenright colonies. This study found no evidence of worker-laid eggs in Vespula wasps, suggesting alternative control mechanisms.
Area of Science:
- Social Insect Behavior
- Evolutionary Biology
- Behavioral Ecology
Background:
- Reproductive conflict is common in social insects, with queens and workers often competing over male production.
- Kin selection theory suggests worker policing, specifically differential oophagy, prevents worker reproduction in multiply-mated queen colonies.
- Empirical evidence for worker egg-laying in queenright colonies remains scarce.
Purpose of the Study:
- To investigate whether workers lay male eggs in unmanipulated, queenright colonies of polyandrous social wasps, Vespula maculifrons and V. squamosa.
- To analyze unusual brood patterns, specifically multiple egg cells, to determine the parentage of developing individuals.
- To test the hypothesis that worker policing via differential oophagy is the primary mechanism controlling worker reproduction.
Main Methods:
- Genotyping of 318 eggs collected from multiple egg cells across eight Vespula maculifrons and two V. squamosa colonies.
- Focus on analyzing the genetic origin (queen vs. worker) of offspring from irregular brood cells.
- Comparison of the frequency of multiple egg cells among different colonies to assess queen-related variation.
Main Results:
- No instances of worker reproduction were detected in any of the studied queenright colonies.
- All eggs found in multiple egg cells were confirmed to be queen-produced.
- Significant variation in the frequency of multiple egg cells was observed among colonies, indicating differences in queen egg-laying accuracy.
Conclusions:
- Worker policing through differential oophagy may not be the primary mechanism suppressing worker reproduction in polyandrous Vespula wasps.
- Workers likely do not lay eggs within queenright colonies of these species.
- Alternative reproductive control mechanisms in Vespula wasps warrant further investigation.
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