THE GRANARY WEEVIL 
Table 1. — Resistance of the granary weevil to starvation 
15 
Date 
Num- 
ber of 
days 
starved 
Number of adult weevils 
found dead at— 
Date 
Num- 
ber of 
days 
starved 
Number of adult weevils 
found dead at — 
55° F. 
60° F. 
68° F. 
70° F. 
85° F. 
55° F. 
60° F. 
68° F. 
76° F. 
85° F. 
1920 
June 24... 
25 
7 
8 
9 
10 
11 
12 
14 
15 
16 
17 
19 
20 
21 
22 
23 

5 



7 
3 


5 
3 
2 
4 
6 
5 




4 
7 

5 
3 
2 



3 


11 
5 



7 


4 


5 

6 
12 
2* 
1920 
July 12... 
14... 
15... 
16... 
17... 
18... 
19... 
20... 
21... 
23... 
29... 
Aug. 3... 
10... 
21... 
25 
27 
28 
29 
30 
31 
32 
33 
34 
36 
42 
47 
54 
65 



3 

2 


1 

1 
1 
1 
1 
7 
6 
2 

7 


3 

1 

3 

4 


3 

2 
12 
4 ! 4 
2 
14 
26 
27... 
28... 
29 
3 
2 

1 
7 
2 

7 
July 1... 
2 
3 
4 
6 
1 
7 
g 
9 
10 
The weevils subjected to a temperature of 85° F. were very active; 
more than 50 per cent died at the end of the first week of starvation, 
a few lingered on for some clays, and one survived for 19 days. The 
weevils kept at 55° F. were sluggish; 50 per cent survived for three 
weeks and one for 65 days. 
DURATION OF ADULT LIFE WITH FOOD 
The average length of life with food, as indicated by the data in 
Table 2, is between 7 and 8 months. 
This is the average of 35 females observed for oviposition records. 
Several individuals not included in this table lived considerably 
longer. Of a number of weevils that emerged on May 1, 1921, one 
female lived until July 2, 1922, and two females until July 10, 1922, 
a period of a little more than 14 months. The effect of a moderately 
low temperature, which permits occasional feeding but at which the 
adults are decidedly sluggish, is greatly to prolong life. Thus, of 30 
adults placed, on September 18, 1921, hi a refrigerator of the ordinary 
type, which maintained a temperature between 50° and 60° F., one 
lived two years and five months and four were still alive on January 15, 
1924. Although adult life may be prolonged to cover a two-year 
period, it is not likely that conditions favoring such a long life obtain 
under normal warehouse conditions. The average length of life, as 
stated above, is about seven or eight months, with certain individuals 
living well over one year. 
PREOVIPOSITION PERIOD 
The data of Table 2 indicate that the granary weevil begins ovi- 
positing from 6 to 148 days after emergence. In early spring females 
begin ovipositing about three weeks after emergences. Later, in 
the summer, the preoviposition period is reduced to approximately 
one week. Weevils emerging late in the fall have the longest preovi- 
position period, since they usually do not begin to oviposit until the 
following springy 
