Lasius

Abstract: Nixon ( 107) , in a detailed survey of the literature on the relations of ants with aphids and coccids showed that until the year 1948 comparatively few critical studies had been made on the nature of the association and on the value of the different benefits received by each partner. He concluded that the evidence did not justify many of the exaggerated claims of a spe­ cial bond uniting the partners to their mutual advantage and, except in a few instances, he questioned the apparent benefits derived by the associated species. Outstanding contributions by Van der Goot ( 136) , Biinzli (27) , and Herzig (65) have now been supplemented by recent experimental work especially on aphids associated with Lasius and Formica spp., and on Pseudococcidae and Coccidae associated with Iridomyrmez humilis Mayr and Oecophylla spp. These ants and their associated Homoptera exemplify different forms of mutualism and are discussed in more detail than are other species. The review is also selective because it is limited to certain controversial topics, namely, adaptations of Homoptera related to their association with ants, benefits derived by the Homoptera, contribution of Homoptera to the food supply of ants, specificity in the ant-Homoptera as­ sociation, and the ant-Homoptera association in relation to their natural control. In this review, the term "mutualism" is defined as an association be­ tween ants and other insects which is mutually beneficial without neces­ sarily implying obligate dependence or interdependence. Myrmecophilous species are those which benefit from ants and are more or less adapted to live with them in a relationship which need not be either obligatory or mutually beneficial.