106 COACTION: THE INTERRELATIONS OF ORGANISMS 



the prairie chicken, mammals smaller than the fox, fishes smaller than 

 the full-grown carp, etc. In addition to this, scatology, pellet study, 

 and the observation of browsed plants have contributed important 

 results for a few of the larger forms. 



Among higher forms occur the various reproductive coactions, in- 

 cluding those of the family as such, which necessarily lead to certain 

 types of social interaction. Naturally, they are likewise part of a 

 composite coaction that includes home making or the securing of 

 food, and they are often combined with disturbance reactions. Out 

 of these basic coactions arise a variety of secondary or correlated 

 ones, more or less distinctive in character but constituting only one 

 feature of a behavior sequence. Such are hunting, storing, combat for 

 the purpose of securing food, materials, territory, slaves or mates, 

 defense and protection, courting, communication, play, etc. In their 

 expression, these are largely an outcome of life form, life history, or 

 life habit, and their development has led to a further specialization 

 of behavior in particular genera and families. 



Consequences of Coaction. In a broad sense, all interactions be- 

 tween organisms may be characterized as helpful, harmful, or destruc- 

 tive to certain species, to the community as a whole, or to man's selfish 

 interests, though there are many degrees of each, and consequent 

 gradations between them. Quite apart from the inequality of coactor 

 and coactee, moreover, is the fact that the same process frequently 

 produces both helpful and harmful effects. This is notably true of 

 aggregation, in which the consequences may be beneficial or injurious 

 to the species concerned, or the two may be combined in varying 

 degree. When the first outweighs the second, the result is coopera- 

 tion in some measure ; if the scales are reversed, the outcome may well 

 be termed disoperation. This comprises several types, of which com- 

 petition is the most important, ranging from mere subordination or 

 displacement at one extreme of efi'cct to complete destruction at the 

 other. 



In respect to individuals, destruction is the typical outcome of food 

 coactions, though this may often affect only parts of the coactee. It 

 is but infrequently the result of coactions involving materials, such 

 as those of leaf-cutting ants and the beaver, but with the noteworthy 

 exception of man as a superinfluent. However, even with respect to 

 food, it is evident that symbiosis and slavery exemplify cooperation, 

 often in a high degree, while the destruction wrought by saprophytism 

 is secondary and of a very different type. Parasitism runs the whole 

 gamut from relations that involve at least a modicum of cooperation 

 through an ascending series of disoperations that terminate in the de- 



