ANIMAL BEHAVIOR, WITH EXAMPLES 



219 



The Rose-Chafer 



VERY year seems to have its 

 prevailing insect pests. Exces- 

 sive numbers of certain species 

 often appear as the result of a 

 lack of the natural enemies that 

 exercise a checking influence over 

 them. In Michigan, I found the 

 rose-bug especially abundant in 

 June, 1906. Originally, it was 

 doubtless a frequenter of the wild 

 rose, but owing, in some degree at 

 least, to the cultivation of the 

 ground and the consequent spread- 

 ing of domestic plants, it has so 

 multiplied and changed its habits 

 that few orchard trees escape its depredations. Its feeding 

 habits also cause it to attack the grape and forest trees, as well 

 as a number of shrubs. I have found it especially troublesome 

 to grapes from the fact that it feeds on the blossoms. Simi- 

 larly, in the year mentioned above, the young peaches were 

 attacked, materially affecting this crop of fruit. 



In the accompanying photographic plate, I have portrayed 

 the rose-chafers in various positions on the wild rose. After 

 feeding a few days on the plants they are capable of eating the 

 blossoms and riddling the leaves with holes. One would think 

 that the sassafras, with its aromatic juices, might be immune 

 from the rose-bug's attacks, but I found the luscious green 

 leaves, upon which the insects gathered in pairs or gregarious 

 colonies, honeycombed, as the result of their voracious appetites. 

 We have noted in another chapter how the large robber-fly 

 attacks the rose-bug and in this way is of great importance in 

 keeping down excessive numbers of these insects. 



Harris says that "the rose-bugs come forth from the ground 

 during the second week in June (Massachusetts), or about 



