Article VII. — The General Entomological Ecology of the Indian 

 Corn Plant* Bv Stephen A. Forbes. 



Ecologj' being the science of the interactions between an organism 

 or a group of organisms and its environment, and between organisms in 

 general and their environment in general, this complex of relations may, 

 of course, be divided in various ways. The division here used implies 

 a centripetal grouping of the facts of relationship around single kinds of 

 organisms, and the group of facts to be discussed is that of which the corn 

 plant is the center and the insects of its environment are the active factors. 



A prolonged .study, extending over many years, of the entomology 

 of the corn plant, the economic results of which have been published in my 

 seventh and twelfth reports as State Entomologist of Illinois (the Eigh- 

 teenth and Twent_\--third of the office series), has left in my possession a 

 considerable body of information capable of treatment from the stand- 

 point of pure ecology, and the beginnings of such a treatment are here 

 assembled because of the rising interest in ecological investigation and 

 the promise which it gives of interesting and important results, and be- 

 cause of a wish to illustrate in some measure the general scientific value 

 of such materials of which, it scarcely need be said, the economic ento- 

 mologists of this country have accumulated a large amount. 



Insect Infestation of the Corn Plant 



We know of some two hundred and twenty-five species of insects 

 in the United States which are evidently attracted to the corn plant be- 

 cause of some benefit or advantage which they are able to derive from it. 

 The principal groups of this series are ninety species of Coleoptera, fifty- 

 six species of larvae of Lepidoptera, forty-five species of Hemiptera and 

 twenty-five species of Orthoptera. The other insect orders are. repre- 

 sented by seven or eight species of Diptera and one or two of Hymenop- 

 tera. Every part of the plant is liable to infestation by these insects, 

 but the leaves and the roots yield the principal supplies of insect food, 

 either in the form of sap and protoplasm sucked from their substance bv 

 Hemiptera or in that of tissues and cells devoured by the subterranean 

 larvtC of Coleoptera and by caterpillars, grasshoppers and beetles feeding 

 above ground. 



Lack of Special Adaptations 



Notwithstanding the great number of these insects and the variety 

 and importance of the injuries which they frequently inflict upon the corn 

 plant, there is little in its structure or its life history to suggest any spe- 



* Repriiiteil from The .Vmtrican Naturalist, Vol. XLIII, No. 5011. Ma.v. litO'.i. 



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