A consistent theme in my research has been a focus on mating systems. I have worked on ant species that exhibit both polygyny (multiple queens per nest) and polyandry (queens that are multiply mated) (Kellner et al 2007, Mol Ecol). I have also worked on ant species that do not mate at all and are clonal (Kellner and Heinze 2011, Kellner et al 2010, 2013ab, Brunner et al 2009, Barth et al 2010). While all Hymenopterans exhibit a sex determination mechanism known as haplo-diploidy (females are diploid and emerge from fertilized eggs, while males are haploid and emerge from unfertilized eggs), around 10 species are known to either lack males, or to produce both males and females from unfertilized eggs. This form of reproduction, known as thelytokous parthenogenesis