ECOLOGICAL 207 



ANOTHER ILLUSTRATION: INTER-RELATIONS OF 

 TERMITES 



The idea of ecological linkages between organisms may be usefully 

 illustrated by taking one kind of animal and showing how many 

 other vital circles its circle intersects. A very good case is furnished 

 by the Termites or White Ants, forming the order or sub-order 

 Isoptera, not in any way related to the true ants, which are included, 

 along with bees and wasps, in the order Hymenoptera. The social 

 organisation of the termites is discussed in connection with social 

 animals; here it is only necessary to say that a typical termitary 

 contains (i) the so-called "king" and "queen", the functional male 

 and female; (2) and (3) two different kinds of fertile "comple- 

 mentals" or reserves, which may be promoted if some evil befalls 

 the royal pair; (4) and (5), normally sterile workers and soldiers, 

 arrested individuals of both sexes, thus differing from the workers 

 among ants and bees, which are always arrested females. 



Most termites live on dead wood or decaying vegetation, and thus 

 they not only assist in the general circulation of matter, but have 

 some role as pruners of trees. That they can thrive on dry-as-dust 

 food is explained by the presence of numerous symbiotic Inf usorians 

 in the food-canal, for these prepare the minute particles for further 

 utilisation by the insects. Most termites are more or less blind and 

 they are perturbed by the glare of day. They also like a slightly 

 humid and very stagnant atmosphere. These conditions are afforded 

 by the nests or termitaries, which are made of salivated earth or 

 chewed wood or both, and though the constructions are often strong 

 enough to bear a man's weight, they submit to weathering in the 

 course of time, and thus contribute to soil-making. The lucifugous 

 workers make earthen tunnels up the stems and along the branches 

 of the trees, and although these are usually very hard, they break 

 down in the long run, and the component particles may be swept 

 away by the torrential tropical rains to swell the alluvium of a dis- 

 tant valley. Thus, in some measure, termites act as soil-makers, 

 though their role in this connection is not nearly so important as 

 that of earthworms. 



Although white ants are not related to true ants, there are some 

 remarkable parallelisms in their habits. Thus both of them some- 

 times cultivate edible fungi, and the termites make intricate laby- 

 rinths of masticated wood, on the walls of which the palatable fungi 

 are grown — another instance of wheels within wheels. Various 

 insects, the "termitophiles", habitually live in association with 

 termites, just as other kinds do with ants; and in both cases the 

 associates may be grouped as predatory intruders, actual parasites, 

 tolerated guests, and much-esteemed pets. The last exude secretions 



