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Ratnieks, along with Tom Wenseleers, took the idea of worker policing further. They pointed out that the better the workers are at stopping each other's attempts at reproduction, the more likely it is for workers to give up, in effect, and simply put all their efforts into the queen's offspring rather than try to produce their own. To test this idea, the scientists compared the proportion of egg-laying workers in ten species of wasps and the honeybee; the insects vary in the effectiveness of worker policing in the nest. As they predicted, workers from species in which the policing is stringent are much less likely to try to lay their own eggs in the first place. The scientists conclude that the insects "provide evidence for something that has proved notoriously hard to demonstrate in human society: that better law enforcement can lead to fewer individuals behaving antisocially."

Ratnieks and Wenseleers also noted that the workers can control each others' reproduction in a different way, by regulating which female eggs end up as queens and which as workers. In many, though not all, social insects, this caste difference is determined during development, with future honeybee queens, for example, placed in larger cells than the plebian workers and fed more of a special substance called royal jelly that jump-starts their growth. Reproducing oneself, rather than caring for the young of others, is an attractive evolutionary prospect, but developing into a queen is only part of the process. It's rather like becoming a movie star: being stunningly beautiful, while essential, is no guarantee of red carpet status. Only a tiny fraction of the queens produced will actually make it to the Oscar-winning equivalent of starting their own hive. But it's not good for the colony if too many individuals become queens, because queens don't do any of the foraging, cleaning, or other mundane tasks of daily life. And yet, as with eager celebrity wannabes, the starlets rush to audition. As Ratnieks and Wenseleers put it, "The lottery to reproduce is so attractive that many more enter than could possibly win the prize of heading a new colony." Policing by the other workers prevents too many queens from being reared, because the larger cells in the comb for rearing queens are strictly limited.

A tropical stingless bee called Melipona provides an elegant illustration of the scope and limitation of policing. Unlike honeybees, which are reared in wax cells that are open at the top so that the workers can feed the larvae a bit at a time over their development, the stingless bee queens are about the same size as workers and are reared in sealed cells, each of which contains its own ration of food. The female Melipona thus develops into an adult without interference from other bees and can become either a queen or a worker. As a result, up to 20 percent of females are aspiring queens. But grim reality sets in once they emerge from their virginal chambers: lack of policing beforehand means that many of the new queens are set upon by the workers and torn limb from limb. The policing ameliorates this carnage by preventing too many queens from being produced in the first place.

Punishment of cheaters who try to reproduce on their own in a social insect colony is not confined to bees. Ordinarily, only queen ants produce a particular chemical on their body's surface to indicate their reproductive status. But if a worker's ovaries develop and she begins to lay eggs, the other workers detect the same odor on her body and attack their sister. Adrian Smith, Bert Hölldobler, and Jurgen Liebig painted workers with the telltale compound and induced the aggression, showing that the odor is indeed the trigger for detection of cheaters. In a colony with its queen removed, however, the newly reproductive workers are left alone.

Ratnieks and Wenseleers ask, "Can humans learn anything from insect policing? The principal lesson seems to be that policing is a common feature of social life and helps to resolve the conflicts caused by the transition from individuals