Myrmecophily 111 



the ants, many of the thorns are depopulated. This 

 seamy side awakens a suspicion that the fitness of 

 the mutual benefit society may have been exaggerated. 



The ant-loving acacias and other plants are called 

 "myrmecophilous," and the theory of myrmecophily 

 is that certain peculiarities of the plants have arisen 

 as adaptive answers-back to the very advantageous 

 presence of the partner-ants. Professor Schimper 

 and other botanists of distinction have lent support 

 to this not unreasonable theory. The food-bodies seem 

 to be transformed glands, but Schimper pointed out 

 that they are "distinguished from all other known 

 glands by definite characters which may, with reason- 

 able certainty, be regarded as special adaptations 

 for the ants' benefit, such as greater size, prolonged 

 persistence, richness in albumen, and easy detach- 

 ment when touched." Moreover the same peculiar 

 food-bodies occur in some plants not related to 

 acacias, and some of these have also partner-ants. 

 Another interesting feature is that the crater-like 

 nectary is away from the usual position of nectaries ; 

 it is extra-floral, situated at the base of the midrib of 

 the leaf. These peculiarities are suggestive of special 

 adaptive arrangements that have arisen in the course 

 of evolution in response to the tenancy of the ants, 

 and in relation to the broad fact, which many natu- 

 ralists confirm, that the ants form an effective body- 

 guard, defending their host from men, cattle, and 

 various kinds of insects. 



But the results of recent investigation have rather 

 shaken the theory of ant-loving plants. There is no 



