4: Surprising evolutionary complexity of queen winglessness in Megalomyrmex Forel, 1885 ants

Reproductive strategies are central to population structuring and the evolution of traits within species. There are 44 Neotropical Megalomyrmex Forel, 1885 species with restricted species ranges and particularly complex life histories. Along with morphological variation, there are remarkable behavioral shifts in how queens found new colonies. Some species have queens that disperse on the wing while others disperse on foot due to queen winglessness. Further, most species are generalist insect predators—but about 1/4^th are social parasites of fungus-growing ants. Their dependence on consuming host fungus and brood likely limits the parasites' distributions. Consequently, Megalomyrmex is an ideal candidate for studying the evolution of reproductive strategies and species dispersal. In this work, we reconstruct the phylogeny, reconstruct the ancestral states, and revise the taxonomy of the genus Megalomyrmex. While winged queen dispersal is an ancestral reproductive strategy, queen winglessness appears to have arisen multiple times in Megalomyrmex. When evaluated in light of geographic distributions, our natural history data indicate that the widely distributed species are those that adopt more than one reproductive strategy (winged and wingless queens). Our work suggests that species with a single reproductive strategy or that are social parasites, have more limited distributions. This is the first study, to our knowledge, to elucidate the evolution of reproductive strategies within an ant genus. Next, we will determine if these strategies and species distributions correlate with morphological features. Our findings contribute to the understanding of how traits evolve and the dispersal potential of species.