Her mother was a daughter of the Durack pastoral family, her father a co-founder of the engineering firm Evans Deakin and Company.

[2] McArthur was a strong environmentalist and a co-founder, with Judith Wright, David Fleay and Brian Clouston, of the Wildlife Preservation Society of Queensland in 1962,[3] and served as vice-president from then until 1965.

Much campaign work was funded through her growing and selling native plants as well as through exhibitions of her wildflower paintings.

She was especially concerned for the Wallum country of South East Queensland, a habitat characterised by floristically rich coastal heath and swamps on deep sandy soils.

She also started the Lunch Hour Theatre in Caloundra, a monthly event for which she wrote scripts based on environmental, biographical and historical subjects.