Australian Dictionary of Biography

James Davidson (1885-1945), ecologist, was born on 27 July 1885 at Brimstage, Wirral, Cheshire, England, second son of James Davidson, shepherd and farm bailiff, and his wife Sarah, née Jones. He was educated at Thornton Hough parish school and the University of Liverpool (B.Sc., 1908; M.Sc., 1911; D.Sc., 1915). After graduating he worked with G. H. F. Nuttall at the Cooper Research Laboratories on his pioneering studies on ticks, major vectors of disease in humans and cattle; in 1911 Davidson was awarded the Wolfe-Barry studentship in entomology at the Imperial College of Science and Technology. He later studied briefly in Italy and France.

In World War I he commanded a sanitary section in Sinai, Palestine and on the Somme, where he organized control of flies, mosquitoes and lice. He was promoted captain and mentioned in dispatches. After the war he was sent to Copenhagen to organize the disinfestation of prisoners; he married his beloved Johanne Therese Hornemann there in 1920; they had three sons and a daughter. Davidson then became assistant entomologist at Rothamsted Agricultural Experiment Station, Hertfordshire, England, studying the effects of aphids on plants, and the influence of soil and climate on aphid populations, exerted through the plant.

In 1928 he migrated to Adelaide to take up a departmental headship at the Waite Agricultural Research Institute in the University of Adelaide. In 1937 he was appointed to the new Waite chair of entomology. In Adelaide Davidson realized that the extremes of climate would have a profound influence on the distribution and numbers of insect species. A leader in the movement to make ecology a quantitative science, he applied rigorous methods to his studies on lucerne fleas, apple thrips, grasshoppers and even the sheep population of South Australia. He developed the concept of 'bio-climatic zones', and mapped Australia into regions where the ratio of rainfall to evaporation determined the limits of distribution of many species. He applied mathematical equations to describe insects' development and the growth of their populations. He set new and exacting standards but was anxious that the man on the land should benefit from research.

Davidson was a humble, gentle, humorous man, with a scientific vision that leapt from painstaking particular observations to the grand generalization. His work contains many detailed studies, always leading towards a general synthesis. His death, on 13 August 1945, following an operation, cut short his major work on the underlying causes of changes in the distribution and abundance of animals. He was buried in the Anglican cemetery at Mitcham. A full bibliography and a more detailed synopsis of his research appeared in the Transactions of the Royal Society of South Australia (1945), of which Davidson had been president in 1937-38.