FOOD PLANTS 



53 



That this is not an imaginary danger can be seen from Fig. 

 8, and from other photographs which we took but have not 

 reproduced in this bulletin, showing the work of the tent cater- 

 pillar upon trees and shrubs not on its usual bill of fare. And 

 the most suggestive fact 

 in connection with these |flB|^ 

 changes of food is to be ^*^ 

 found in the great dis- 

 similarit}' of the other 

 food plants. The apple 

 and cherry belong to the 

 great rose family of plants ; 

 botanically speaking they 

 are related to each other 

 as well as to the rose, the 

 peach, the pear, the plum, 

 the mountain ash, and 

 others. It is well known 

 that insects have family 

 preferences in the matter 

 of food ; that if a given 

 insect feeds upon a given Fig. 9— Diseased Tent Caterpillars (Original) 

 plant we need not be sur- 

 prised to find it also upon another plant closely related, belong- 

 ing to the same family. 



In view of this we should expect the tent caterpillar when it 

 was forced to increase its range of food to attack the peach, culti- 

 vated cherry, rose, and other plants of this family. This has 

 been done, and each of these is now on the tent caterpillar's 

 food list, but we have also found it feeding freely and appar- 

 ently thriving upon such widely separated plants — so far as 

 botanical kinship is concerned — as the oaks (Fig. S), the hicko- 

 ries, the birches, (see photograph on title page,) the barberry, 

 and the willows and poplars. I found a large tent even upon 

 the low evergreen known as the juniper, but the caterpillars 

 from it evidently fed upon a neighboring barberry. 



