IV.—ANTS IN THEIR DIVERSE RELATIONS TO THE PLANT WORLD By J. Beqttaert The following contribution is an attempt to summarize what is known at present of the widely varied and often intricate relations which exist in nature between ants and vegetation. It has primarily grown out of an examination of certain so-called "myrmecophytes,"or ant-plants, which I frequently came across during my travels in the Belgian Congo in quest of zoological and botanical specimens. Prof. Wheeler's study of the feeding habits of the larvae of certain plant-inhabiting ants collected by Messrs. H. Lang and J. P. Chapin and myself in the Congo, and Prof. I. W. Bailey's investigation of the anatomy of myrmecophytes show that the whole subject of the mutual adaptations of plants and ants is in need of a thorough revision. It thus seemed appropriate that the present opportunity be used to bring together the many isolated and scattered observations which have been made on the interrelations of these organisms. Indeed, the problem of myrmecophytism is dominated by the feeding habits of the ants and their young and, until these are perfectly understood, we can scarcely hope to grasp the true ecological meaning and the probable origin of the extreme cases of apparent or true symbiosis between certain ants and certain species of plants. It is, therefore, of the utmost importance to inquire carefully into the various ways in which ants are wont to benefit by the vegetation. Although much time has been spent in consulting botanical and entomological papers for information bearing on the subject, undoubtedly a number of interesting observations have escaped my notice. In keeping with the general purpose of the present contribution to African Myrmecology, especial attention has been paid to work accomplished in the tropics, primarily in Africa. The bibliography appended to this part is as complete as possible. In it are included many papers which may seem to have but remote connection with the subject—such as, for instance, those on fungus-growing termites, intracellular symbionts, and the like. I believe, however, that they are indispensable in reference to the study of certain activities of ants. Some students may find the botanical side rather too fully treated, but this seemed unavoidable m providing the necessary background for future field work, especially to the myrmecologist. Moreover, I am convinced that the ultimate solution of many of the problems involved can only come from a close cooperation between botanical and entomological experts, and this, under present conditions of specialized training, is not so easily realized. 333 |