50 



Marvels of the Universe 



THE LEAF-CUTTING ANT 



BY EDWARD STEP, F.L.S 



In tropical America there dwells an ant about the same size as the Red Ant of British .pinewoods. 

 It is known in different localities as Sauba-ant and Coushie-ant. Most naturalists who have 

 travelled in that part of the world have told us of their admiration at the sight of long processions 

 of these ants streaming down the trunks of trees and along definite tracts through the forest to their 

 great nest-heaps, every ant holding in his jaws a circular piece of leaf. The ants are almost hidden 

 by these umbrellas, and the procession looks more like a stream on whose surface the leaves are 

 floating. It was for long a puzzle what the ants did with these leaves, and it was variously suggested 



that they were used for food 

 and for lining or roofing the 

 galleries of their nests. The 

 facts of the case, as usual 

 where Nature is concerned, 

 are far more wonderful than 

 the theories. The ant packs 

 these leaves into its cellars, 

 where they rot and form a 

 soil for the cultivation of a 

 fungus which serves as food 

 for the ant-grubs. When the 

 fungus has drawn all the 

 nutriment from this leaf- 

 mould, it is carefully cleared 

 out of the nursery galleries 

 into spare-chambers, where it 

 is eaten up by the grubs of 

 certain beetles, such as ants 

 always encourage, or at least 



shape closely resembles the leaf-laden anl toleratC, iu their neStS. ShaftS 



lead from the galleries where these fungi are grown to the outer air, and the temperature and 

 humidity of the gallery is regulated by opening or stopping up the shafts as circumstances may 

 require. 



An unprotected plant-sucking insect, known as a membracid, that occurs in the same region, 

 has developed a green hood, which covers its back in such a way as to closely resemble a Coushie-ant 

 with its cut leaf, as shown in the illustration above It has been suggested that this is a case of 

 protective mimicry, and that the ants pass the membracid under the impression that it is one of 

 themselves, and similarly engaged. 



The underground galleries of this ant are very extensive. Bates tells that they had infested 

 the Botanic Gardens at Para so much as to arouse the indignation of a French gardener there, who 

 set to work to try to exterminate them, or at least to reduce their numbers. His plan was to discover 

 the main entrances to and exits from their nests, and over these to burn sulphur, and blow the heavy 

 fumes into them by means of bellows. In this he was so successful that the destructive vapour 

 entering at one point was seen to be coming out of other holes far away from the burning sulphur 

 Bates measured the distance between the entrance of the vapour and one of its exits, and found it 

 to be no less than two hundred and ten feet And all the intervening space was tunnelled by a net- 

 work of the ants' galleries. Truly a prodigious piece of engineering for creatures so small. 



THE COUSHIE OR LEAF-CUTTING ANT. 



A single ant is here shovv'n on its downward passage alon 

 portion of leaf it has just cut. The nearer insect is a membrai 



i; a branch with the 

 id that in colour and 



