colony production and greater efficiency. Moreover, based on the kin-selection theory, it is collectively beneficial for all the individuals in the community to have the queen to lay eggs rather than the workers lay eggs. This is because if the workers lay eggs, it benefits the egg-laying worker individually, but the rest of the workers are now twice removed from this worker's offspring. Therefore, though it is beneficial for one individual to have its own offspring, it is collectively beneficial to have the queen lay the eggs. Therefore, a system of worker and queen policing exists against worker-laid eggs. One form of policing occurs by the oophagy of the worker-laid eggs, found in many ant and bee species. This could be done by both or either the queen or the workers. In a series of experiments with honeybees (Apis mellifera), Ratneiks & Visscher found that other workers effectively removed worker-laid eggs in all colonies, whether the eggs were from originated from the same colonies or not. An example of a combination of queen and worker policing is found in ants, in the genus Diacamma, in which worker-laid eggs are taken by other workers and fed to the "queen". In general, these signals that identify the eggs as queen-laid are likely incorruptible, since it must be an honest signal to be maintained and not be used by cheating workers. The other form of policing occurs through aggression towards egg-laying workers. In a species of tree wasp Dolichovespula sylvestris, Wenseleers et al. found that a combination of aggressive behavior and destruction of worker-laid eggs kept the number of worker-laid eggs low. In fact, 91% of the worker-laid eggs were policed within one day. They also found that about 20% of workers laying eggs were prevented from doing so through both the queen's and workers' aggressive behavior. The workers and the queen would grab the egg-laying worker and try to sting her or push her off the cell. This usually results in the worker removing her abdomen and not depositing her eggs. Policing/punishment in other organisms Aggression and punishment are not just found in insects. For example, in naked mole rats, punishments by the queen are a way she motivates the lazier, less-related workers in their groups. The queen would shove the lazier workers, with the number of shoves increasing when there are fewer active workers. Reeve found that if the queen is