He is an expert on introduced ants, especially the globally invasive Argentine ant, Linepithema humile. His research on native populations of invasive species demonstrated the utility of a biogeographic approach to understanding invasion success, pioneering an approach that is considered the gold standard in the field. He also conducts research on trap-jaw ants, whose mandibles are among the fastest biological movements. Suarez is a recipient of the 2017 University of Illinois Campus Award for Excellence in Undergraduate Teaching. He also is affiliated with the IGB.