Tags: Entomologist.
Alexander John Nicholson (25 March 1895 – 28 October 1969) was an Irish Australian entomologist who specialised in insect population dynamics. He was Chief of the CSIR / CSIRO Division of Economic Entomology for 24 years and is credited with initiating the professional era in Australian entomology. He was a Foundation Fellow of the Australian Academy of Science.He is notable for the Nicholson–Bailey model.