Given the short life span of the adult pollinating fig wasps and the lack of synchrony of fig production, how then is the relationship maintained? Usually on emergence the female wasps have to leave the tree they bred on, because the figs in a particular crop are normally all at the same stage of development. Some Ficus species, however, have figs at different stages of development within the same crop and in these cases the female wasp has only to fly a short distance to locate a receptive fig. The cycling of the mutualism can, therefore, continue on the same tree. More commonly the cycling phenomenon relies on the presence of a suitably sized population of trees of a particular species in a given area, so that somewhere within the population there will be a tree with figs that are receptive for pollination. The lack of synchrony in fig crop production between trees is an essential trait to ensure this. If all the trees in a population produced figs at the same time, the fig wasp population would die out. Local extinctions of wasps do occur, when they are not able to locate a tree with figs in the receptive phase, and there will also be abortions of fig crops that pollinators have not managed to locate. Nevertheless, in the larger picture this is a very successful interaction, which is borne out by the high diversity of both fig trees and fig wasps.