The stinging pattern of a predatory wasp is a behavioural trait, affecting the possible evolutionary changes of its niche, e.g. widening or shifting the prey spectrum. We tested the hypothesis that the ability of a predator to adjust its handling effort to the size of prey is a species-specific trait, the parameters of which depend on the size and size range of the exploited prey. We found that wasps better adjust their stinging effort to prey size if they hunt relatively larger or relatively more variable prey. This adaptability differs amongst neighbouring phylogenetic lineages. We presume that evolution of prey-handling behaviour may result in two types of tactics: the first, an application of precise techniques for optimal prey immobilization, little dependent on prey size and typical of specialists. The second tactic typical of generalists is a less precise handling, causing more general damage to the prey with an intensity dependent on its size.