8 B.C. ExTOJiOLOGiCAL Society. 



I'>ut I shoukl liUe to refer to some very interesting partuersliips where not only .1 

 temporary acquaintance is made witli eacli otlier, bnt wliere botli insect and plant 

 have found it to their mutual advantage to live friendly. 



Ants protect Plants. 



Perhaps the most outstanding example is to be found in Mexico. The mere 

 mention of that country may give a clue to the reason for the partnership. In 

 Mexico there is an Acacia (,Acacia sphwroccpliala) which is subject to the attacks 

 of herbivorous quadrupeds. A common means of protection against these has been 

 adopted by converting the stipules into spines. This not being sufficient, an arrange- 

 ment has been made for a fierce race of stinging-ants to act as a standing army, 

 which the Acacia has undertaken to keep, in peace or war. 



The ants pierce the bases of the spines and eat out the interior; this stimulates 

 the spines to increase in size, sufficient to accommodate several of these soldiers in 

 each cavity. The Acacia^ has compound pinnate leaves, and at the tips of the leaflets 

 small grain-like food-bodies are produced. The ants are continually running over the 

 plant attending to these, picking and eating them when matured. 



In addition to free board and lodgings, the ants are provided with free drinks, 

 in the form of nectar exuded by minute saucer-shaped nectaries borne on the midrib 

 of the leaf. 



Altogether, the ants have some reason to defend this hospitable Acacia, and, in 

 return, unwelcome visitors are accorded such a warm reception that it has proved 

 a quite successful means of defence. 



Plants protect .Vnts. * 



In tropical forests ants often find difficulty in keeping their accumulations of 

 debris together on account of the liability of being washed away by heavy rains. 

 These heaps are usually formed on the branches of trees because the surface of the 

 earth is more or less swampy, but the ants have found that by including seeds and 

 small portions of certain plants an abundance of roots ramify throughout the heap, 

 and help to keeiJ it together ; whilst the mass of foliage covering it is sufficient to 

 break the force of the rain, or help in divertiug it from the ant's home. We find 

 that many plants grow best in such situations, and on this account are included 

 amongst the myrmecophilous, or ant-loving, plants. 



One genus of plants, round in Malacca and New Guinea, has been named 

 Hijfliwphytum foiinicaruin on account of its symbiotic relationship with ants. The 

 plant is epiiihytic (living on the branches of trees), and at an early stage in its 

 development it is attacked by black ants, who eat their way into the tuber. 

 Ultimately a large irregular-shajied ball-like structure develops, through which a 

 whole mass of galleries and i)assages ramify and anastomose, serving as a hom(! 

 with many doors for entrance and exit. One can readily understand that the tuber 

 now transformed into an anfs nest will be well looked after b,y the inhabitants. 



Inqenuity of Methods of Higher Plants. 



I can only briefly refer to the insectivorous plants, and if I had time to describe 

 the ingenious traps of Dionwa, 'Nepenthes, Utricuiaria, Drosera, and others, I think 

 you'd agree that truth is certainly stranger than fiction. 



To hear how some plants set miniature rat-traps to Instantaneously capture 

 insects ; how others tempt insects by intoxicating fluid, and that when under its 

 irffluence they are drowned and utilized as food ; how other jjlauts lure the unwary 

 insect to partake of an imaginary feast only to find that the apparent drops of nectar 

 were viscid glands ou the ends of sensitive hairs which, like the arms of a gigantic 

 octopus, envelop the struggling creature, I am sure you'd agree that their ingenuity 

 would be hard to beat. 



