AN EXPERIMENTAL INVESTIGATION OF AN APPAR- 

 ENT REVERSAL OF THE RESPONSES TO LIGHT 

 OF THE ROACH (PERIPLANETA 

 ORIENTALIS L.). 



C. H. TURNER, 

 SUMNER HIGH SCHOOL, ST. Louis, Mo. 



Roaches are nocturnal animals, they shun the light and seek the 

 darkness. This has been well known for years; according to 

 Szymanski, Graber 1 is to be credited with thoroughly demonstrat- 

 ing this. According to my observations, it would be incorrect 

 to call this a case of negative phototropism, if we use the term in 

 the sense that Loeb uses it ; for there is no orientation to the rays 

 of light, but simply a scampering hither and thither until some 

 dark hole or crevice is found, into which the roach immediately 

 rushes. Normally these roaches are exceedingly shy and any 

 attempt to touch or handle them is responded to by suddenly 

 darting away. Even the slightest touch is sufficient to cause 

 them to run away. In these experiments an attempt has been 

 made to apply the electrical punishment method devised by 

 Yerkes 2 when experimenting with white mice to a study of the 

 light reactions of one of the common roaches. 



HISTORICAL RESUME. 



To the best of my knowledge, this method has been used only 

 once in the study of insect behavior; that was by Szymanski, 3 

 who has recently made such a study of ten larval cockroaches of 

 the species Periplaneta orientalis L. He studied ten male 

 roaches all of the same age. Based on their ability to learn and 

 upon evidences of fatigue, Szymanski classifies roaches as follows; 

 those that with practice make rapid progress and fatigue slowly, 



1 Graber, V., "Grundlinien zur Erforschung des Helligskeits- und Farbensinnes 

 des Tiere," Prag, 1884, pp. 147-157. 



2 Yerkes, R. M., "The Dancing Mouse," New York, 1907, pp. 98-99. 



3 Szymanski, J. S., "Modification of the Innate Behavior of Cockroaches," 

 Jour, of An. Behavior, 1912, Vol. II., pp. 81-90. 



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