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Cannibalism, the process of killing and consuming conspecifics, can become enhanced by various environmental stresses. Organisms inhabiting Mediterranean habitats are better adapted for coping with competition-an adaptation that can manifest itself in increased cannibalism. Conversely, desert environments are characterized by long periods of food shortage, also selecting for cannibalism to overcome starvation. We tested for differences in the frequency of cannibalism between Mediterranean and desert populations of pit-building antlions. We also quantified the frequency of cannibalism within and between these populations. We could not detect a significant geographic variation in the frequency of cannibalism. We suggest that strong plastic responses to environmental stresses buffer against divergent selection, and thus no significant differentiation in cannibalism rate should occur. Cannibalism frequency was higher in mixed pairs comprised of individuals originating from different populations within and between climate regions, compared with that observed within populations. We suggest that this intraspecific discrimination ability is mediated by behavioral and/or chemical cues, associated with co-occurrence in a common environment, as well as by genetic relatedness.