110 
Psyche 
[December 
CANNIBALISM AMONG LEPIDOPTEROUS LARVAE 
V. G. Dethier 
Biological Laboratories, Harvard University 
The occurrence of the carnivorous habit in lepidopterous 
larvae is known in certain rather widely separated groups, 
one of which, the Lycaenidae, is outstanding (Brues, 1936). 
It is known also that some phytophagous larvae will become 
carnivorous for a period of time either regularly or in the 
absence of a plentiful food supply (Brues, 1920). I have ob- 
served this and also cannibalism many times while breeding 
various species. 1 A few examples may be cited. 
When larvae of the Arctiid, Apantesis arge Drury, were 
confined to a limited area (three to four larvae to eight square 
inches) with a moderate supply of food, the smallest, least 
healthy, or least active larva was usually attacked while still 
alive and almost entirely eaten by a more robust specimen. 
Fifty of these larvae were divided into lots of two, three, and 
four, each lot being limited to an area of eight square inches. 
In nearly seventy-five percent of all cases cannibalism oc- 
curred. It was noted more frequently when four larvae were 
confined together or when one larva was smaller or weaker 
than its neighbors, as stated above. Moore (1912) reported 
that Phcebis eubule L., when confined even in the presence of 
an ample food supply, ate smaller larvae of its own species. 
The more aggressive individuals also devoured the more 
peaceful ones. Perkins (1928) found that Nemoria viridata 
L. in the presence of an abundance of food also showed can- 
nibalistic tendencies. The larvae from a large batch of eggs 
feasted upon one another till there was but one left. This 
animal pupated and a normal adult emerged. Subsequent 
breedings with other batches of eggs of the same species 
revealed no further cases of cannibalism. 
I have observed that larvae of Estigmene acrxa Drury and 
Diacrisia virginica Fab. when confined with those of other 
"Tor cases of oophagy see Schultz (1928, 1935). 
