The general paradigm is that, in ants, queens produce two types of

eggs : Unfertilized eggs that develop into males and fertilized eggs

that develop into females. The general consensus is also that caste

determination results from environmentally‑induced differences in gene

expression with females eggs being able to develop either into queens

or workers depending on the social environment. In this talk I will

present exceptions to all these " rules ". In some species there is a

genetic basis of caste determination. In others, queens use alternate

mode of reproduction (sexual or asexual) to produce queens and workers.

Finally, we uncovered one case where males produce males by clonal

reproduction. These systems provide ideal grounds to study the

resolution of within colony conflicts.