26 
BULLETIN" 427, U. S. DEPARTMENT OF AGRICULTURE. 
RELATION OF FOOD TO OVLPOSLTION. 
Experiments to test the effect of feeding on oviposition show 
that both the period of opposition 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 
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 mating. 
January. . . 
April./.... 
June 
August 
November 
Ovi- 
position 
period. 
Days. 
Total 
109 
247 
262 
294 
142 
September and October also showed large egg records, 27 out of 35 
adults under observation depositing over 200 eggs each. 
EFFECT OF FERTILITY ON OVrPOSLTION. 
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 in much smaller numbers. 
Table 6 shows some of the greatest variations to be found in this 
connection . 
