AUTHOR 8 ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE, OCTOBER 5. 



THE RELATIVE INFLUENCE OF FOOD AND OXYGEN 

 IN CONTROLLING SEX IN ROTIFERS 1 



DAVID DAY WHITNEY 



Zoological Laboratory, University of Nebraska 



FOUR FIGURES AND FOUR DIAGRAMS 



It has been shown in a former paper that in five different 

 species of rotifers the production of male-producing females and 

 female-producing females can be regulated at will by certain 

 manipulations of the food supplies. In some species a continu- 

 ous diet of a colorless flagellate, Polytoma, caused only female 

 producing females to be produced but when a green flagellate, 

 Chlamydomonas, was substituted for the colorless flagellated 

 food nearly all male-producing females were produced. In one 

 species, the only one upon which such experiments were made, a 

 scanty diet of pure cultures of the green flagellate, Chlamydo- 

 monas, caused all or nearly all female-producing females to be 

 produced while a more abundant diet of the same pure cultures 

 of Chlamydomonas caused as high as 90 per cent of male-produc- 

 ing females to be produced. 



Shull and Ladoff working with Hydatina senta have since sug- 

 gested and indicated in the results of their experiments that an 

 excess of oxygen in the culture water may cause a greater pro- 

 duction of male-producing females than in experiments without 

 an excess of oxygen. 



Since the publication of the former paper experiments have 

 been carried on with four additional species of rotifers which also 

 showed that a scanty diet of food caused female-producing fe- 

 males to be produced while a copious diet caused male-producing 

 females to be produced. These species used were identified by 

 Harry K. Harring, Custodian of the Rotatoria in the United 

 States National Museum, to whom I am greatly indebted. 



1 Studies from the Zoological Laboratory, The University of Nebraska, No. 

 118. 



101 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 24, NO. 1 



