The 24 carabid species investigated appeared to be polyphagous, but not equally so. Among species showing a smaller degree of polyphagy, oligophages and specialized feeders were distinguished, the latter species specializing on collembolans. The phytophagous genera Amara and Harpalus were found to behave similarly to the generalists. Cannibalism was not observed, although larvae, among which it may well occur, were not studied. Specialists are mainly confined to the Carabinae, and the literature suggests that they can also be distinguished by their morphology and behaviour, which reflect their specialization. It seems unlikely that their specialization is in response to food shortage.
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R. Hengeveld (1979) studied this question.