And it’s benefits…
This is my reference list so far. I can’t find a copy of the Ratnieks article on nature though. I will be coming back to this and trying to write a full answer on worker policing.
Colony benefits – resources aren’t wasted on excess drones.
Queen benefits – that only her eggs are nurtured.
Nature benefits – genetic diversity by worker drones being raised, can produce changes faster.
In terms of inclusive fitness, honey bee workers gain from policing other workers’ eggs because a worker is more related to her mother queen’s sons (0.25) than to other workers’ sons (0.15) (Ratnieks 1988). (Honey bee queens mate with approximately 10-30 males; the relatedness of 0.15 occurs at an effective paternity frequency of 10). Both the signal producer (queen) and the receivers (police workers) benefit from the egg-marking pheromone because it helps the colony to rear more related males (queen perspective: sons (0.5) versus grandsons (0.25); police worker perspective: brothers (0.25) versus nephews (0.15)). However, a worker is more related to her own sons (0.5) than to brothers (0.25) so there should still be selection for worker bees to lay eggs if attempted
reproduction has little cost to the colony.
Although egg policing does not directly prevent workers from laying eggs, it should greatly reduce the incentive for them to do so (Ratnieks, 1988; Visscher, 1989; Ratnieks & Reeve, 1992; Bourke, 1999). Hence, Ratnieks (1988) suggested that social policing could potentially select for workers to ‘self-police’, i.e. to choose not to reproduce even when they possess functional ovarie
Is policing a universal mechanism that can promote cooperation in biological systems? Possibly it is, although there are two caveats. First, individuals could evolve resistance to policing, which could lead to transitional ‘episodes of revolution’. For example, in some lines of anarchistic honeybees, the workers cheat by laying eggs that are not policed (Barron et al., 2001). Secondly, there are examples of conflicts where policing is simply not possible (Beekman et al., 2003). For example, in social Hymenoptera, developing females cannot be prevented from selfishly turning into queens when queens and workers are the same size and develop away from social interference in closed cells (Bourke & Ratnieks, 1999; Wenseleers et al., 2003; Wenseleers & Ratnieks, 2004). This occurs in Melipona stingless bees, where as a result of such ‘caste fate conflict’, queens are continually overproduced (Wenseleers & Ratnieks, 2004). Nevertheless, our analysis clearly demonstrates that when policing is possible, it can be a much more efficient mechanism than pure kinship for promoting cooperation within social groups (cf. Frank, 1995; Wenseleers et al., 2003; Wenseleers & Ratnieks, 2004).