This takes place throughout the summer and early autumn and involves the sexual progeny of the queen (normal males and the females she has turned into queens) mating to ensure the colony survives the winter. At this point, the grubs within the nest that worker wasps have been surviving on start dying, forcing them to find alternative sustenance, which is when they become a more visible nuisance to humans trying to eat outside. This is the point at which exterminators will normally be contacted.