Mutualism effects of within and among-tree flowering in a desert fig Ficus petiolaris

摘要

Figs (genus Ficus; Family Moraceae) represent one of the most commonly referenced obligate pollinator mutualisms. Within the obligate pollinator mutualism, each fig species relies upon a single species of pollinator wasp for pollination services while the pollinators rely upon the flowers of that single fig species to oviposit offspring within. In order to maintain reproductive assurance and mutualism function, figs at a population level must flower asynchronously among trees. This ensures that when the short-lived pollinator wasps are released from pollen donating flowers, there will also be pollen receptive flowers available. As fig populations decline, the fig and fig-wasp mutualism is expected to suffer from reproductive limitations and local wasp extinctions as the probability of among-tree reproductive phase overlap declines. In this study we investigate how asynchronous within-tree flowering and among tree floral correlations may cause us to over or underestimate the amount of pollen limitation in small populations of a desert fig Ficus petiolaris. We discuss selective pressures that influence both within and among tree flowering synchrony and how changes in flowering may influence the fate of both figs and fig-wasps, most notably those with keystone characteristics or of conservation concern.