 In Polistes exclamans , equal sex ratio is obtained when only 46 @.@ 3 % of investment is devoted to females as female wasps are 1 @.@ 16 times larger than male wasps . In a study done by Strassmann , it was found that sexual investment is female biased , especially during years of high predation and when nests are generally less successful . It has been seen that in Polistes exclamans , females are produced before males . This female investment bias may result from the ability of females to become either a worker or a reproductive ( this is more adaptive for the nest as it gives the nest increased flexibility compared to that of males and may be important for overall nest success ) or because females provide the colony with greater nest defense . Furthermore , even when the original queen is no longer present , the sexual investment is still biased towards females , which is not expected given the genetic implications of a new queen . 
