In field-collected egg masses more than 21% of the eggs were destroyed by first-instar larvae from the same egg mass. Since 39.8% of these were estimated to be nonviable, the effective reduction in number of larvae owing to egg cannibalism by undispersed first-instar larvae was 12.7%. Cannibalistic behavior has been stated to have survival value, since this food supply lengthens the life and increases the chance of finding prey by otherwise nonfed larvae. Laboratory experiments showed that cannibalism lengthens the life span, but results also in larvae which disperse from the egg mass later and are less active than noncannibalistic larvae, so their chances of finding prey are reduced. Cannibalism might still be an advantage under low-prey-density situations were it not for the known fact that this species can maintain itself and mature on substances other than prey. Therefore, this behavior may not be advantageous to the role of larvae as natural control agents.
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Robert L. Pienkowskp (1965) studied this question.