Queen Control of Sex Ratio in Fire Ants

  title={Queen Control of Sex Ratio in Fire Ants},
  author={Luc Passera and Serge Aron and Edward L. Vargo and Laurent Keller},
  pages={1308 - 1310}
The haplodiploid sex-determination system of ants gives rise to conflict between queens and workers over colony sex ratios, and the female-biased allocation ratios seen in many species suggest that workers often prevail in this conflict. We exchanged queens between male- and female-specialist colonies of the fire ant Solenopsis invicta. These exchanges quickly reversed the sex-ratio biases of adopting colonies. The sex ratio of queen-laid eggs differed strongly between male- and female… 

Sex Allocation Conflict in Ants: When the Queen Rules

Sex allocation conflict between queens and workers in Formica pratensis wood ants predicts seasonal sex ratio variation

The resulting seasonal alternation of sex ratios between queen and worker optima is a novel demonstration how understanding constraints of sex ratio adjustment increases the ability to predict sex ratio variation.

Dual mechanism of queen influence over sex ratio in the ant Pheidole pallidula

It is shown that queens regulate colony sex ratio in two complementary ways: by determining the proportion of female eggs laid and by hormonally biasing the development ofFemale eggs into either a worker or reproductive form.


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.

Patterns of split sex ratio in ants have multiple evolutionary causes based on different within-colony conflicts

An overview of the main conditions favouring split sex ratio in ants is provided, showing that each split sex-ratio type arises due to a different combination of factors determining colony kin structure, queen or worker control over sex ratio and the type of conflict between colony members.

Ant workers selfishly bias sex ratios by manipulating female development

This work uses microsatellite analyses to show that, in a population of the ant Leptothorax acervorum, workers' relatedness asymmetry is significantly higher in monogynous (single–queen) colonies than in polygynous (multiple–queens) colonies, and this finding strongly supports kin–selection theory.

Primary sex ratio regulation by queens in ants (Formicidae) and other social Hymenoptera

Current knowledge on primary sex ratio control by queens in social Hymenoptera, especially ants is reviewed, the most classical methods forPrimary sex ratio determination are presented, and empirical studies showing a regulation of the relative number of male and female eggs laid by queens as a function of demographic, ecological and socio-genetic factors are outlined.




  • K. Helms
  • Biology
    Evolution; international journal of organic evolution
  • 1999
Sex‐ratio conflict between queens and workers was explored in a study of colony sex ratios, relatedness, and population investment in the ant Pheidole desertorum, and results are generally consistent with that study.

Conditional Manipulation of Sex Ratios by Ant Workers: A Test of Kin Selection Theory

Variable queen mating frequencies provide a unique opportunity to study the resolution of worker-queen conflict over sex ratio in social Hymenoptera, because the conflict is maximal in colonies

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.

Worker-queen conflict and sex ratio theory in social hymenoptera

The queen may have considerable control over the investment ratio; two factors which may act in favour of worker control are a high cost of producing a new queens rather than a worker and the possibility of making a variable investment in a new queen with a concomitant variation in her fitness.

Queen‐worker conflict over sex ratio: A comparison of primary and secondary sex ratios in the Argentine ant, Iridomyrmex humilis

Workers exert a control on the secondary sex ratio by eliminating a proportion of the male brood during the period of sexual production and eliminating all the males during the remainder of the cycle, consistent with workers preferring a more female‐biased sex ratio than queens.

Sex–ratio regulation: the economics of fratricide in ants

The results indicate that workers did not replace male brood with new females, but rather reduced total brood size during late larval development, suggesting that the evolution of fratricides in ants is best explained by a combination of ecological, demographic and genetic parameters.

Sex investment ratios in monogyne and polygyne populations of the fire ant Solenopsis invicta

The sex investment ratios of monogyne and polygyne populations of S. invicta are consistent with at least partial worker control, and there is limited support for the hypothesis that greater resource abundance favors investment in females.

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.

Testing kin selection with sex allocation data in eusocial Hymenoptera

Signs of worker control were found by investigating proximate mechanisms of sex ratio manipulation in ants and wasps, and further manipulative experiments will be needed to disentangle the multiple evolutionary factors and processes affecting sex allocation in eusocial Hymenoptera.