INSECT ECOLOGY 393 



V. COMMUNITIES 



In a given habitat the fauna and flora together constitute a biota. 

 'he term fauna is generally used in connection with classification or 

 geographical distribution, as is also the term flora. In reference to 

 :ological relations, however, the animals or plants of a given habitat 

 ;onstitute a community. 



As animals and plants, according to their structural resemblances or 

 lifferences, fall into species, genera, families, orders, etc., so do animal 

 >r plant communities, according to their ecological likenesses or unlike- 

 tesses, fall into mores, consocies, strata, associations, and formations; 

 tch of these orders being inclusive of the preceding kind; there the 

 ^semblance ends. The animals of a community agree in their reactions 

 the factors that they encounter. If they meet environmental influ- 

 ences in the same way, they are said to be ecologically similar; if they 

 meet the same influences in different ways, they are ecologically equiva- 

 lent. Thus a caterpillar that meets low temperature by making a co- 

 .coon, and one that gets the same result by digging into the ground, 

 are ecologically equivalent/ Animals select their habitats, probably by 

 trial and error ; and their behavior becomes adjusted to the surrounding 

 conditions. (Shelf ord.) " The habitat is the mold into which the organ- 

 ism fits. Since habitats are different, animal communities occupying 

 different habitats are physiologically different. Communities are sys- 

 tems of correlated working parts." (Shelford.) 



"Mores -are groups of organisms in full agreement as to physiological 

 life histories as shown by the details of habitat preference, time of 

 reproduction, reactions to physical factors of the environments, etc. 

 The organisms constituting a mores usually belong to a single species 

 but may include more than one species. 



"Consocies are groups of mores usually dominated by one or twoof 

 the mores concerned and in agreement as to the main features of habitat 

 preference, reaction to physical factors, time of reproduction, etc. 

 Example: the prairie aphid consocies. The aphids dominate a group of 

 organisms which for the most part prey upon them, as, for instance, 

 certain species of lacewing, lady beetles, syrphus-flies, etc. 



"Strata are groups of consocies (and animals not so grouped) occupy- 

 ing the recognizable vertical divisions of a uniform area. Strata are in 

 agreement as to material for abode and general physical conditions but 

 in less detail than the consocies which constitute them. 



"For example, a forest-animal community is clearly divisible into 



