38 
Psyche 
[March 
FOOD PREFERENCES OF THE COLORADO POTATO- 
BEETLE, LEPTINOTARSA DECEMLINEATA SAY. 
By Charles T. Brues 
Biological Laboratories, Harvard University 
The experiments 1 here described were undertaken some 
years ago (1923-25), but no account of them was published 
at that time as a report on work of a somewhat similar na- 
ture by others appeared while my own was still in progress. 
More recently one or two additional papers relating to the 
choice of food-plants by the Colorado potato-beetle have been 
published and the whole question appears worthy of review 
with incorporation of the data secured by the present writer. 
Aside from its importance as an insect pest of cultivated 
potatoes the Colorado potato-beetle is of particular interest 
on account of an apparent shift in its food-habits which oc- 
curred less than a century ago when it was first noted as 
feeding on the foliage of the potato. However, the food 
preferences of this beetle are not so clear as might appear 
from this statement and they have already furnished in- 
teresting material for study at the hands of several ento- 
mologists in this country and in France where the species 
has been naturalized since about 1920. 
The potato-beetle was described by Thomas Say in 1824 
from the western plains region and was regarded by him as 
native to the United States. There seems to be no reasonable 
doubt that this supposition was in error and that the origi- 
nal habitat was Mexico. At the time of its discovery by 
Say and for several decades later the beetle appears to have 
restricted its feeding to the foliage of a common weed of the 
Southwest, Solanum ( Androcera ) rostratum. This plant in 
turn is of Neotropical origin and is thought to have preceded 
the beetle, and to have become naturalized in the United 
1 1 wish to express my gratitude to the Elizabeth Thompson Fund for 
a grant which made possible the construction of a series of large out- 
door cages in which the breeding experiments were conducted. 
