484 University of California Publications in Zoology 1T L - H 



The finding of scorpions in the stomachs of two meadowlarks 

 from San Diego was a surprise for two reasons. Their size and 

 sting would apparently protect them. In addition, their noc- 

 turnal habits and their habitat would seem to offer protection. 

 That more were not taken is probably due to the fact that they 

 are seldom available rather than that they are unpalatable. 



The investigation has, therefore, shown that insects suppos- 

 edly protected by noxious secretions, malodor, stings, etc., are 

 taken as food by western meadowlarks. According to the old 

 idea, the survival of these insects can be traced directly to pro- 

 tective adaptations. Earty authors even suggested almost com- 

 plete immunity from attack. In recent years this view has become 

 modified. Judd (1899) called attention to the fact that "Biol- 

 ogists have not yet entirely elucidated all the details of the nature 

 of adaptations of insects which are potently protected." The 

 same thing can be said at the present time. 



If we hold to the theory of natural selection, it is important 

 that a certain toll be taken in order to perfect adaptation. If 

 an insect had no enemies it would have little need of protective 

 adaptations. Of course it may be argued that after the adapt- 

 ation becomes perfected the enemies of insects learn to let them 

 alone. Unless the variations were of the orthogenetic type, how- 

 ever, we could hardly expect such highly differentiated protective 

 adaptations to exist as do exist. Kellogg 's view that "success" 

 is dependent on protective adaptations rests on this assumption. 

 It overemphasizes the part played by protective adaptations. In 

 the working of the principle of natural selection other principles 

 and tendencies are working against the factor of protective 

 adaptations, and it cannot be said that protective adaptations 

 gain the ascendency over all other tendencies. 



Unusual destruction of so-called protected insects and other 

 arthropods can sometimes be attributed to young birds. Finn 

 (1898) found out by experiment "that each bird has to separately 

 acquire its experience, and well remembers what it has learned. 

 Lloyd Morgan (1896) has also shown that birds have no instinc- 

 tive knowledge of the different kinds of food, but that they 

 examine and test everything. He also points out the fact that 

 they have excellent memories and are able to remember sum"- 



