JOIia 
Voi,. XXIV Washington, D. C., April 28, 1923 No. 4 
STUDIES ON THE TEMPERATURE OF INDIVIDUAL 
INSECTS, WITH SPECIAL REFERENCE TO THE 
HONEY BEE' 
By Gregor B. Pirsch * 
Minnesota Agricultural Experiment Station 
INTRODUCTION 
More observations have been made on the temperature of the bee 
colony than on the individual bee. Phillips and Demuth(j< 5 )^ concluded 
that bees, essentially cold-blooded animals, were capable of regulating 
their temperature when in a colony by increasing the temperature of the 
colony when the air temperature went down and lowering the tempera¬ 
ture of the colony when the air temperature went up. Since Phillips and 
Demuth have shown that the colony, which is composed of a large num¬ 
ber of individuals, acts very much as a warm-blooded animal does, the 
temperature of the individual must be of great importance. If this were 
not true, it would be difficult to understand how the colony of individuals 
could control its temperatures. For this reason and because of the wide 
variation in the results obtained by previous workers this problem was 
chosen for study. 
In a review of the literature on this subject it was found that previous 
workers had based the results of their observations on a few individuals. 
The results included in this paper are based on the readings of over i,ooo 
bees. The methods and results of the previous workers are given in the 
following review of the literature. 
REVIEW OE literature 
Hausmann (ro) was the first to establish the temperature of an indi¬ 
vidual insect. He placed a Sphinx convolvuli together with a small 
thermometer in a glass receptacle, the air temperature of which was 17^ 
JR.. (21.25° C-)- After half an hour the temperature had risen to 19° R. 
(23.75° C.) and soon after fell to 17° R. Experiments with Carabus 
hortensis gave the same results. 
1 Accepted for publication June 29, 1922. Published with the approval of the Director as paper No. 383 
of the Journal Series of the Minnesota Agricultural Experiment Station. . ^ 
2 The work on which this paper is based was done in the laboratories of the Division of Entomology of 
the University of Minnesota. To the members of the staff, and especially to Dr. R. N. Chapman, tmder 
whose immediate direction the study was conducted, acknowledgments are due for apparatus furnished 
and for constant helpful suggestions. 
* Reference is made by number (italic) to “Literature cited,*' p. 286-287. 
Journal of Agricultural Researdi, 
Washington, D. C. 
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