Annual Report of the Board of Regents of the Smithsonian Institution for the Year ending June 30, 1896 pp. 421-422
The biologic relations between plants and ants
Dr. Heim
Associate of the Faculty of Medicine at Paris

Along the edges of the leaves of the Rosa Banksiae are found perifoliary nectaries that attract great numbers of a large black ant (Camponotus pubescens). The presence of these ants preserves the rose from the attacks of a hymenopterous insect (Hylotoma rosae). We owe an interesting experiment upon this subject to Beccari. On a branch of Rosa Banksiae attacked by ants he placed a branch of another rose bush attacked by the larvae of Hylotoma. Incommoded by the ants, these larvae took refuge upon the youngest buds, unprovided as yet with nectaries, and consequently not visited by ants. It is to be remarked that the Banks rosebushes, which are rarely or never attacked by Hylotomas, are destitute of prickles. We may probably admit that there is a correlation between the presence on plants of thorns or prickles and that of leaf-eating insects. Is it not due to the protection given by ants and other sting-bearing hymenoptera that the Banks rosebushes attain the great age that some of them are known to do? We may cite as an instance one of these bushes planted in 1803 by Bopland in the garden of the marine hospital at Toulon, which has a stem a meter in diameter at the base and bears each year from fifty to sixty thousand flowers.

The leaves of peach, apricot, and cherry trees may, as there is reason to suppose, be derived from compound leaves. The nectaries which they carry on the petioles should then have the significance of aborted leaflets filled with sweet stores.

Huth: Myrmecophile und myrmekophobe Pflanzen. pp 14-15 (1887)