ZD 



J3Ui.LETlJSI rzt, JJ. S. DEPARTMENT OF AGEICULTTJEB. 



EELATION OF POOD TO OVIPOSITION. 



Experiments to test the effect of feeding on oviposition show 

 that both the period of oviposition and the number of eggs laid may 

 be increased by feeding. In these experiments some of the moths 

 were kept in dry vials, some in vials with a little water, and others in 

 vials with sugar water. Those kept with water were under condi- 

 tions more like those outdoors, while the ones in dry vials would be 

 under extreme laboratory conditions. 



The results are shown in Table 4. 



Table 4. — Relation of food to oviposition of the potato tuber moth. 



Nature of experiment. 



Number 



of 

 adults. 



Total 

 eggs de- 

 posited. 



Average 

 number 



of eggs 

 per 



female. 



Without food 



10 

 10 

 10 



1,138 

 1,472 

 2,094 



114 



Water. 



147 





209 







Temperature also has a very important effect, not only on the 

 rapidity with which eggs are laid, but on the number as well. During 

 the winter months, when the nights become cool, very few eggs are 

 deposited by an adult, and these are well scattered. The period of 

 oviposition is longer during a season of cool nights, but even this 

 does not make up for the fewer eggs laid, as will be seen in Table 5. 



Table 5. — Effects of temperature on oviposition of the potato tuber moth. 



Pair of adults matiag. 



Ovi- 



Total 



position 



egga 



period. 



laid. 



Days. 





17 



109 



14 



247 



8 



262 



9 



294 



13 



142 



January. . . 



April 



June 



August 



November 



September and October also showed large egg records, 27 out of 35 

 adults luider observation depositing over 200 eggs each. 



EFFECT OF FERTILITY ON OVIPOSITION. 



Unfertilized females were isolated at different seasons of the year 

 to test the effect on oviposition. Almost all of these deposited eggs 

 at some time during their lives, but the eggs were deposited irregularly 

 and m much smaller numbers. 



Table 6 shows some of the greatest variations to be found in this 

 connection. 



