“…Empirically, acquiescence can explain the observed low levels of reproductive workers found in insect societies with effective policing, such as the honeybee (Ratnieks 1993) or the common wasp (Foster and Ratnieks 2001a), and the rarity by which females cheat on their intended worker fate, which only occurs at low levels in a minority of genera (e.g., in some stingless bees; Engels and Imperatriz-Fonseca 1990;Imperatriz-Fonseca and Zucchi 1995;Ribeiro and Alves 2001;Wenseleers et al 2003;Wenseleers et al 2005c) and is entirely absent in most (e.g., in the honeybee; Winston 1987). The ultimate endpoint of acquiescence is the evolution of obligate worker sterility in some species, for example, in Atta, where workers are unable to lay viable eggs (M. Dijkstra, personal communication) and in Linepithema, Monomorium, Pheidole, and Solenopsis ants and Frieseomellitta and Duckeola stingless bees, where workers have evolutionarily lost ovaries altogether (Oster and Wilson 1978;Cruz-Landim 2000). However, because it is currently unknown whether these genera ancestrally had queen or worker policing, we cannot test whether worker sterility has indeed evolved in response to policing or whether alternative factors may have been the main cause.…”