Yellow-jacket wasps live to serve their mother, the queen, but will kill her if she fails to secure more than one mate.
Colonies of yellow-jacket wasps (Dolichovespula arenaria; pictured) have a single queen that generates female workers, which rarely reproduce, and reproductive males. But Kevin Loope at Cornell University in Ithaca, New York, found that just under half of colonies eventually revolt, with the workers killing their queen and producing their own males. To find out why, Loope collected wasp nests and measured the workers' relatedness. Matricide was most common in colonies where workers were more closely related to each other.
This means that the queen had only one mate, making workers less closely related to the queen's sons than to the sons of other workers. Workers prefer males that are more closely related to them, so it benefits them to overthrow the queen and produce their own sons.
Curr. Biol. http://doi.org/8vz (2015)