Apr. 28,1923 Studies on the Temperature of Individual Insects 
285 
Tabi«^ III .—Comparison of body temperatures of Carniolian and Italian bees at various 
air temperatures 
Number of bees 
pierced. 
Air 
tempera- 
Average body 
temperature. 
Difference be¬ 
tween body and 
air temperatures. 
Maximum body 
temperature. 
Minimum body 
temperature. 
Camio- 
lians. 
Ital¬ 
ians. 
ture. 
Camio- 
lians. 
Italians. 
Carnio- 
lians. 
Italians. 
Camio- 
lians. 
Italians. 
Camio- 
lians. 
Italians. 
10 
8 
10 
8 
2.5 
5-5 
8. 0 
9.0 
30.0 
35 '0 
52.0 
•c. 
4.9 
8.5 
13 '2 
13-8 
32. I 
35 '0 
46.3 
•c. 
5 'I 
8.5 
•c. 
2.4 
3-0 
S '2 
4.8 
2 . I 
0. 0 
- 5'7 
®C. 
2. 6 
3'0 
"C. 
7 
9 
16 
16.5 
33 '0 
35 '0 
48. 0 
“C. 
6 
9 
®C. 
4 
8 
11-5 
12.5 
31*5 
34 - 5 
45'5 
^C. 
4-5 
8.0 
25.0 
12.5 
10 
25 
25 
25 
10 
13.6 
4.6 
16. 0 
freezing point 
A study of the freezing point and the phenomenon of supercooling of 
the bee was made. An ether bath and a potentiometer were used. The 
ether bath was more easily controlled than an ice bath, and the tempera¬ 
ture dropped about 0.5^ C. per minute. Care was taken not to move the 
bee or have it come in contact with anything, as the least amount of 
movement will bring about the freezing of the insect. If the insect is 
moved or shaken about the time the rebound from supercooling to the 
actual freezing point is to take place, the bee will freeze and the rebound 
is not evident. It was also found that if the temperature of the bee 
when nearing its freezing point went down slowly, the freezing would 
take place and there would be no supercooling with a rebound to the 
freezing point. However, if the temperature went down rapidly as it 
neared the freezing point, the bee was supercooled and the rebound 
occurred. Three individual bees were taken down to —2.3°, when 
there was a rebound to —0.8°, or the actual freezing point. Another 
bee was supercooled to —4.3°, when the rebound occurred, the tem¬ 
perature going up to —2°., the actual freezing point. This conforms 
with the results obtained by Bachmetjew. The variation in the results 
is probably due to the fact that individuals do not have the same freezing 
point. 
SUMMARY 
The large variation in the results obtained by the early workers was 
due to the differences in methods of performing their experiments. 
Many of the old workers used mercurial thermometers, or thermocouples, 
which were then just coming into use. Nobili and Melloni (75) were 
the first to ever use this method. Because of the wide variation and 
unrefinement of the methods used by the early workers and the results 
they obtained their work remains only of historical value. 
Bachmetjew {2) has contributed considerably to the general work 
on insect temperature by bringing together and giving a summary of 
the older works. In addition to this, he has performed many original 
experiments on the temperature of individual insects. 
Brunnich (j) is the most recent worker on the temperature of bees. 
The lack of uniformity in his results is undoubtedly due to the fact that 
