Joseph Parker is an evolutionary biologist studying the evolution of symbiosis in rove beetles that live with ants. He uses molecular and genomic tools to explore how these beetles evolved from free-living ancestors to symbiotic lifestyles. Parker discovered that at least 12 myrmecoid lineages evolved from a common ancestor around 100 million years ago, showcasing convergent evolution. His research on the beetles’ abdominal tergal gland revealed its evolution from two cell types, highlighting how new multicellular organs originate. This work challenges the view that evolution is largely unpredictable over long timeframes.