Bates' studies on mosquitoes contributed to the understanding of the epidemiology of yellow fever in northern South America.
[2] He worked for the Rockefeller Foundation from 1935 to 1952, studying mosquito ecology, malaria, yellow fever, and human population.
[2] During that time, he also served as member of the National Research Council's expedition to the Ifalik Atoll in the South Pacific (1953), director of research at the University of Puerto Rico (1956-1957), and member of the Committee on Biological and Medical Sciences of the National Science Foundation (1952-1958).
In 1960, he published the ecological science book The Forest and the Sea,[7] an introduction to how ecosystems work.
He compares a rain forest and a tropical sea, their similarities and differences, and through it demonstrates how to understand biological systems.