Colony‐level sex ratio selection in the eusocial Hymenoptera

  title={Colony‐level sex ratio selection in the eusocial Hymenoptera},
  author={Jacobus J. Boomsma and Alan Grafen},
  journal={Journal of Evolutionary Biology},
We present an inclusive fitness model on worker‐controlled sex investments in eusocial Hymenoptera which expands the existing theory for random mating populations as formulated by Trivers and Hare (1976) and Benford (1978). We assume that relatedness asymmetry is variable among colonies — owing to multiple mating, worker reproduction and polygyny — and that workers are able to assess the relatedness asymmetry in their own colony. A simple marginal value argument shows that “assessing” workers… 

Sex Ratio Conflict and Worker Production in Eusocial Hymenoptera

A simple and general kin selection model that allows us to calculate the evolutionarily stable investments in the three castes, while varying the identity of the party controlling resource allocation, shows that queens and workers favor the investment in workers that maximizes lifetime colony productivity of sexual males and females, whatever the colony kin structure.

On the Robustness of Split Sex Ratio Predictions In Social Hymenoptera

Using inclusive fitness models, this study determines the optimal patterns of split-sex-ratio allocation for hymenopteran workers when colonies have a single queen, and queens mate with either one or

Sex investment ratios in eusocial Hymenoptera support inclusive fitness theory

  • A. Bourke
  • Biology
    Journal of evolutionary biology
  • 2015
It is argued that the Wilson–Nowak sex ratio hypothesis is flawed because it contradicts Fisher's sex ratio theory, which shows that selection on sex ratio does not maximize the number of mated offspring and that the sex ratio proposed by the hypothesis is not an equilibrium for the queen.

Colony level sex allocation in a polygynous and polydomous ant

Both the alate and wingless sex ratios may be influenced by a common primary sex ratio at the egg stage, the variance of which may have genetic components.

Reproductive alliances and posthumous fitness enhancement in male ants

It is shown that males of the ant Formica truncorum achieve manipulation by partial sperm clumping, so that the cohort–specific relatedness asymmetry of the workers in colonies with multiple fathers is higher than the cumulative relatednessymmetry across worker cohorts.

Split sex ratios in the social Hymenoptera: a meta-analysis

A meta-analysis shows that workers often bias colony sex allocation in their favor as predicted by split sex ratio theory, even if their control is incomplete and a large part of the variation among colonies has other causes.

Sex investment in a social insect: the proximate role of food

It is demonstrated that food supply has an important proximate influence on sex investment, and may explain much of the natural variation in sex investment in populations of eusocial Hymenoptera.


It is predicted that population and colony level sex allocation, as well as colony productivity, will differ diagnostically according to whether queens or workers evolve alternative biasing strategies and according to what mechanism workers use to bias sex allocation.

Reproductive parameters vary with social and ecological factors in the polygynous ant Formica exsecta

The sex ratio was extremely male biased in a polygynous (multiple queens per nest) population of the ant Formica exsecta, which shows that both, social and ecological factors can influence long-term nest reproductive strategies in insect societies.

Sex ratio biases in termites provide evidence for kin selection.

It is shown that kin selection can result in sex ratio bias in eusocial diploids, and this model predicts that allocation will be biased towards the sex that contributes more of its genes to the next generation when sex-asymmetric inbreeding occurs.




It is predicted that worker‐controlled sex investments in eusocial Hymenoptera should maximize their inclusive fitness by specializing in the production of the sex to which they are relatively most related, i.e., colonies whose workers have a relatedness asymmetry below the population average should specialize in males.

Ant Reproductive Strategies and Sex Allocation Theory

  • P. Nonacs
  • Biology
    The Quarterly Review of Biology
  • 1986
An analysis of a wide body of literature on ants strongly supports the genetic relatedness hypothesis (GRH), and the bimodal sexual investment pattern appears to be a mixed "evolutionary stable strategy and state" and seems proximately determined by the amount of food resources.


  • F. Ratnieks
  • Biology
    Evolution; international journal of organic evolution
  • 1991
A single‐locus two‐allele model is analyzed to determine the invasion conditions for facultative biasing of colony sex allocation by hymenopteran workers in response to queen mating frequency, for a

Sex ratio strategies in Formica ants

Stability of both colony and population sex ratios, and the similarity of sex ratios in conspecific populations living in similar environments, suggest that the sex ratios can be considered as adaptive strategies produced by genetic evolution.

Reproductive Investment and Allocation Ratios for the Ant Leptothorax longispinosus: Sorting Out the Variation

Variation residual after path analysis showed that unmeasured parameters were important for reproduction patterns in this species, and the most likely unme measured determinants were resource-acquisition ability, not adequately estimated by worker number, and investment in colony growth.

Worker Reproduction in the Higher Eusocial Hymenoptera

  • A. Bourke
  • Biology
    The Quarterly Review of Biology
  • 1988
The analysis of data assembled on 49 ant species reveals that workers in monogynous species (i.e., with one queen per colony) reproduce moslty in queenless conditions, whereas those in polygynous species reproduce in queensless and queenright conditions equally often, in agreement with kinship theory.

Assessment of queen mating frequency by workers in social hymenoptera

Fisher's theory of the sex ratio applied to the social hymenoptera.

  • F. Benford
  • Biology
    Journal of theoretical biology
  • 1978

Worker-queen conflict in annual social hymenoptera