THE BIOLOGIC RELATIONS BETWEEN PLANTS AND ANTS. 1 



By Dr. Heim, 



Associate of the Faculty of Medicine at Paris. 



Ill the study of natural sciences it is often an excellent plan to begin 

 by stating a well-worn truism. To say, in the present state of our 

 knowledge, that close relations exist between plants and insects is to 

 utter such a truism. 



At the close of the last century the wonderful discoveries of Koel- 

 reuter followed by those of Sprengel had already demonstrated such 

 relations. It was upon the teachings of that genial thinker that was 

 built a great part of the theory of selection given definitive form by 

 the labors of Darwin. At that period, however, the relations between 

 plants and insects, even when viewed by the light of evolution, were 

 considered almost solely with regard to the cross-fertilization of vege- 

 table organisms. The biologic relations between plants and ants have 

 been fully examined only by our contemporaries. Though the topic is 

 one of extraordinary fecundity, it is but little known to the general 

 public. 



Among the subjects that biology offers for our consideration some are 

 especially fortunate in that their exposition requires no personal talent, 

 their interest depending upon a mere recital of facts. One of these 

 privileged subjects is the relations of plants and ants, and this selfish 

 consideration has led me to choose it for my remarks. 



As a preliminary to the study of the relations of ants to living vege- 

 table forms it will be well to rapidly examine the organs that insects 

 use in establishing such relations. We need not dwell upon their legs, 

 which are very movable and constructed upon the general plan of the 

 legs of insects. The claws that terminate them are used by ants in 

 clinging to rough surfaces, in scratching the ground, iu rejecting refuse, 

 in holding food. Between the claws are found very delicate organs, 

 the pulvilli, by whose aid the insect can cliug to smooth surfaces, 

 whether vertical or horizontal, against the force of gravity, by 

 means of an oily secretion that causes the foot to adhere by capillary 



'Translated from the Compte Rendu de la 24me Sess. de l'Association Francaise 

 pour l'Avancement des Sciences, 1895, premiere partie, pp. 31-75. 



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