Effective population size in eusocial Hymenoptera with worker-produced males

Area of Science:

• Evolutionary Biology
• Population Genetics
• Social Insect Ecology

Background:

• In many eusocial Hymenoptera species, female workers reproduce, producing a proportion of the males.
• The impact of worker reproduction on population genetic parameters, particularly effective population size (N(e)), is not fully understood.

Purpose of the Study:

• To derive a general expression for effective population size (N(e)) in Hymenoptera considering male production by workers.
• To evaluate the effect of worker reproduction on N(e) under various breeding sex ratio conditions.

Main Methods:

• Derived a general expression for N(e) based on genetic drift of a neutral allele.
• Utilized stochastic simulations to validate the derived N(e) expression across diverse conditions.
• Performed numerical computations using the derived expression to analyze N(e) trends.

Main Results:

• Worker reproduction was found to generally reduce effective population size (N(e)).
• The reduction in N(e) is more pronounced in populations with unity or female-biased breeding sex ratios.
• N(e) may increase under male-biased sex ratios if workers produce few males and progeny number variation is low.

Conclusions:

• Worker reproduction significantly impacts effective population size (N(e)) in Hymenoptera.
• The findings suggest worker reproduction is a key factor contributing to the typically lower genetic variation observed in Hymenoptera.
• Understanding worker reproduction dynamics is crucial for explaining genetic diversity patterns in social insects.