Worker policing

Worker policing has been suggested as a form of coercion to promote the evolution of altruistic behavior in eusocial insect societies.

[2][3][4] In rare cases, worker-laid eggs carry mimicked queen hydrocarbons and escape policing, a condition known as the anarchic syndrome.

[5] Not all forms of policing require the presence of a queen; it also occurs in a few species of ants which establish a dominance hierarchy of reproductive female workers, where top-ranking individuals reproduce.

This results in a conflict in which the queen and worker females are at odds over the proportion of male offspring they contribute, since each side tries to maximize its reproductive fitness.

Researchers who study these wasps have observed a strong positive correlation between worker relatedness and male production.

After controlling for the absolute number of eggs laid, these scientists conclude that the queen's multiple matings favor mutual worker policing.

[9] Although early theories of worker policing focused on the kin selection component, evidence from honey bees suggests that altruism is sometimes enforced.

A study of the carpenter ant Camponotus floridanus found a special surface hydrocarbon on queen-laid eggs.

Specifically, the old reproductive workers rubbed a marker hydrocarbon on the antennae of the new females, identifying them as rivals and targets for aggression.

Workers displayed higher levels of aggression toward non-nest mates and also removed some queen-laid eggs.

[8] In many of these hives, the activation of ovaries in fertile females is diminished, suggesting that there are disincentives to laying eggs.

[8] Workers in colonies of the dwarf honey bee, Apis florea, are also reported to engage in oophagy.

Using microsatellite analysis, researchers concluded that no mature drones had non-queen alleles in the colonies they investigated.

The species has gamergates, which lay eggs but rarely carry out any other tasks, so having too many of them would reduce the colony's efficiency.

The signal used by the policing workers consists of cuticle hydrocarbons transmitted only by direct contact, rather than being a pheromone detected by olfaction.

[23] In a test of worker policing, researchers examined the removal of worker-laid eggs in Vespula rufa, a wasp that has low paternity.

[24] The European Hornet, Vespa crabro, was previously thought to be under reproductive pheromone control by the queen, thus explaining why the other females did not reproduce, even though they were capable of doing so.

Anarchic syndrome is an example of selection working in opposite directions at individual and group levels.

Individuals do not act in benefit of the colony, instead opting to increase their own fitness by laying their eggs and reducing the contributions of opponents.

For example, more time spent on individual reproduction would be predicted to detract from care of the queen's offspring.