I 



34 TEXTBOOK OF ZOOLOGY 



Agriculture and Zoology 



It may frequently bring a smile to the lips of an onlooker to see 

 a full-grown and perhaps intelligent zoologist enthusiastically at- 

 tempting to learn what, when, and how much a little boll weevil 

 eats or when, where, and how it lays its eggs ; and yet, the discovery 

 of such information may influence the activities of our entire cotton 

 industry. A recent instance of the economic importance of zoo- 

 logical knowledge is found in the saving of the entire citrus industry 

 in Florida from the Mediterranean fruit fly. Injurious insects alone 

 cause an annual loss in the United States of more than one and 

 one-half billion dollars ' worth of products if they could be sold at 

 the price the remaining portion brings. With proper knowledge of 

 animal life and application of this knowledge it is likely that at 

 least half of this loss could be prevented. Losses almost as impor- 

 tant are caused each year by the parasitism of our domestic animals 

 by bacteria, protozoans, worms, and insects. The knowledge and 

 application of parasitology, which is a field of zoology, would avoid 

 this loss. 



Agriculture has benefited greatly from the application of the 

 principles of heredity to plant and animal breeding. Much funda- 

 mental knowledge has come from the extensive studies on the 

 genetics and breeding of the common fruit fly, Drosophila. It is 

 easily kept in the laboratory and mated. It produces a new gen- 

 eration about once every nine days. More improvement of strains 

 of animals and plants too, can be made in one man's lifetime than 

 was previously possible through ages. The United States Department 

 of Agriculture and the United States Department of Interior have 

 taken the lead in much of this type of zoology. 



Fisheries and the Application of Zoology 



A very practical and profitable application of zoology has been made 

 in the fishing industry. The annual salmon catch alone on the Pacific 

 coast has been known to be worth $25,000,000. The fishing industry 

 cultures, collects, and markets not only fish of many kinds but also 

 oysters, clams, lobsters, crabs, shrimp, and even sponges. The United 

 States Fish and Life Service does an extensive and remarkable work 

 in the study, propagation, and care of this natural zoological re- 

 source. Even with this work and that of all the State Fisheries 

 Departments, the natural fish life does not flourish as it might, had 



