Transactions of the Royal Entomological Society of London

Abstract

The general question of associations between ants and species of Acacia in the Ethiopian and Neotropical regions is discussed in the light of detailed studies of some aspects of the association in East Africa between Acacia drepanolobium and Crematogaster mimosae, C. nigriceps and Tetraponera penzigi. The cause of the swelling of stipular thorns in Acacia and the survival value of the association for both the ants and the Acacias are discussed. Accounts are given of, in the Acacia, density and altitude distribution, tree form, and the development and geometry of swellings; in the ants, of population densities, temperature conditions, energy relationships, activity and behaviour, and associated insects and other animals. A possible origin of the association is discussed.