EVOLUTION OF INTERSPECIES INTEGRATION AND ECOSYSTEM 



721 



doubtless benefit from subtle physiological, 

 behavioristic, and population relationships 

 that are largely uninvestigated. 



an interspecies supraorganism. An interspe- 

 cies system with organismic attributes 

 surely exists (p. 440) and is a highly en- 



Fig. 259. Termitophilous staphylinid beetles from the nests of Constrictotermes cavifrons in 

 British Guiana: a, Spirachtha schioedtei recently emerged from pupa case, in profile; b, 

 Spirachtha mirabilis from above, physogastric form with three pairs of abdominal exudatoria; 

 c, same, in profile, showing recurved abdomen with lateral exudate glands. 



Considering the high degree of coopera- 

 tion at the individual and population level 

 of integration, it is somewhat surprising to 

 find that the evolution of interspecies co- 



Fig. 260. Ptochomyia sp., a physogastric ter- 

 mitophilous fly ( Termitoxeniidae ) with re- 

 duced wings from the nest of Macrotermes 

 natalensis, Belgian Congo. 



operation is less obvious and more difiicult 

 to demonstrate. This conclusion should not 

 be used to argue against the existence of 



lightening ecological concept (for an op- 

 posed interpretation, see Bodenheimer, 

 1938). 



The action of natural selection in guid- 

 ing the evolution of genetically continuous 

 intraspecies systems produces a degree of 

 cooperative interrelationship not attained 

 to such a marked degree when selective 

 pressures guide genetically isolated organ- 

 isms with ecological continuity. 



THE INTERSPECIES SUPRAORGANISM 



In the foregoing discussion of the evolu- 

 tion of interspecies systems, species pairs 

 have been chosen in the main because 

 they illustrate the simple, fundamental 

 ecological relations between genetically dis- 

 continuous organisms. However, even a 

 brief survey of any biocoenose reveals a 

 great multiplicity and intertwining of in- 

 numerable interrelationships. There is dan- 

 ger that the whole may not be perceived 

 from a focus on its basic parts. 



The complexity of a small biocoenose 

 may be partially illustrated by a diagram 

 (Fig. 261) of the factoral relations (Emer- 



