LITERATURE FOR 1916 ON THE BEHAVIOR OF 

 SPIDERS AND INSECTS OTHER THAN ANTS 



C. H. TURNER 



Sumner High School, St. Louis. Mo. 



TROPISMS AND RELATED PHENOMENA 



Winn (119) thinks that certain butterflies exhibit phototro- 

 pisms. 



A trap net, with a bright lantern as a lure, was hauled across 

 a field on a slowly moving wagon. A much larger variety of 

 insects was captured than were enticed into stationary lure 

 nets. Hence Holloway (48) concludes that a moving light has 

 a greater attraction for insects than one that is fixed. 



Runner (90) describes experiments upon the effects of roent- 

 gen rays on the cigarette beetle. 



Richardson (86) finds that the house-fly is attracted by both 

 ammonium hydrate and ammonium carbonate. He also notes 

 (85) that the odor of ammonia attracts a varied dipterous aggre- 

 gation; and that all of the species thus responding are known to 

 spend at least part of their lives in some animal excrement. 

 Since practically all animal excrement gives off ammonia, he 

 concludes that it is probably the ammonia gas which attracts 

 flies to manure. 



In the behavior literature of today, the tropism hypothesis 

 holds a prominent place. There have been protests against its 

 universal application; but, so v/idespread is the impression that 

 the complex acts of insects can be resolved into tropisms that 

 these protests are popularly considered the anthropomorphic 

 effusions of non-critical minds. Each year the number of stu- 

 dents who are unwilling to subscribe unreservedly to the tropism 

 hypothesis increases. This year Pictet (79), after a critical 

 analysis of numerous experiments, concludes that the locomo- 

 tions of insects are not phototropisms. According to him: 

 ' The tropism theory does not harmonize with the variety of 

 ways an organism responds to a given stimulus. ... It 

 has not been demonstrated that the ascending and descending 



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