Professor Simmons, a Federation Fellow at the University of Western Australia, transformed our understanding of mate choice and sexual selection through scholarly synthesis, ingenious experiments, and development of novel empirical models from the Australian insects. Important contributions include recognition that female choice of mates can occur cryptically after copulation through sperm assortment, showing why female-female competition over mates only occasionally develops in response to evolution of paternal care, and demonstrating the benefits that females gain from polyandrous mating. His prodigious output includes a major book and eight papers in Nature or Science, and attracts more than 500 citations annually.