144 CO ACTION: THE INTERRELATIONS OF ORGANISMS 



Wheeler's term, "trophallaxis" (cf. page 154) , while the many special 

 trophic relations among ants belong to the general category of para- 

 sitism, or "parasitoidism" (AVheeler, 1923:196, 200). Forel (1930:250) 

 would include under symbiosis "the more or less constant and intimate 

 union of one species with another," but his definition and its applica- 

 tion take in various types of parasitism. The resulting confusion in 

 thought is exemplified by his statement in connection with the tree 

 Cecropia that "on the side of Azteca, symbiosis is complete and suc- 

 cessful, and the plant does not suffer in any way, rather the reverse"! 

 Apart from the symbiotic trophism of adult and young, the most con- 

 vincing examples of mutualism are to be found in the coactions between 

 ants and aphids, coccids, etc., the so-called ant cattle (Forel, loc. cit., 

 page 492; Wheeler, page 178). For a concise but comprehensive 

 account of the food coactions of ants, the reader should consult 

 Wheeler, and further details are to be found in the two volumes of 

 Forel. In the case of the bird-insect nesting relations described by 

 Moreau (1936; Myers, 1929, 1935), an incomplete symbiosis appears 

 to be involved in certain cases, but little is known of the cause and 

 nature of the coaction in which birds build their nests alongside those 

 of social insects. 



