Ficus Aurea - Ecology

Ecology

Ficus aurea is a strangler fig—it tends to establish on a host tree which it gradually encircles and "strangles", eventually taking the place of that tree in the forest canopy. While this makes F. aurea an agent in the mortality of other trees, there is little to indicate that its choice of hosts is species specific. However, in dry forests on Great Exuma in The Bahamas, F. aurea establishes exclusively on palms, in spite of the presence of several other large trees that should provide suitable hosts. Eric Swagel and colleagues attributed this to the fact that humus accumulates on the leaf bases of these palms and provides a relatively moist microclimate in a dry environment, facilitating seedling survival.

Figs are sometimes considered to be potential keystone species in communities of fruit-eating animals because of their asynchronous fruiting patterns. Nathaniel Wheelwright reports that Emerald Toucanets fed on unripe F. aurea fruit at times of fruit scarcity in Monteverde, Costa Rica. Wheelwright listed the species as a year-round food source for the Resplendent Quetzal at the same site. In the Florida Keys, F. aurea is one of five fruit species that dominate the diet fed by White-crowned Pigeons to their nestlings. F. aurea is also important in the diet of mammalian frugivores—both fruit and young leaves are consumed by black howler monkeys in Belize.

The interaction between figs and fig wasps is especially well-known (see section on reproduction, above). In addition to its pollinators (Pegoscapus mexicanus), F. aurea is exploited by a group of non-pollinating chalcidoid wasps whose larvae develop in its figs. These include gallers, inquilines and kleptoparasites as well as parasitoids of both the pollinating and non-pollinating wasps.

The invertebrates within F. aurea syconia in southern Florida include a pollinating wasp, P. mexicanus, up to eight or more species of non-pollinating wasps, a plant-parasitic nematode transported by the pollinator, mites, and a predatory rove beetle whose adults and larvae eat fig wasps. Nematodes: Schistonchus aureus (Aphelenchoididae) is a plant-parasitic nematode associated with the pollinator Pegoscapus mexicanus and syconia of F. aurea. Mites: belonging to the family Tarsonemidae (Acarina) have been recognized in the syconia of F. aurea and F. citrifolia, but they have not been identified even to genus, and their behavior is undescribed. Rove beetles: Charoxus spinifer is a rove beetle (Coleoptera: Staphylinidae) whose adults enter late-stage syconia of F. aurea and F. citrifolia. Adults eat fig wasps; larvae develop within the syconia and prey on fig wasps, then pupate in the ground.

As a large tree, F. aurea can be an important host for epiphytes. In Costa Rican cloud forests, where F. aurea is "the most conspicuous component" of intact forest, trees in forest patches supported richer communities of epiphytic bryophytes, while isolated trees supported greater lichen cover.

Florida International University ecologist Suzanne Koptur reported the presence of extrafloral nectaries on F. aurea figs in the Florida Everglades. Extrafloral nectaries are structures which produce nectar but are not associated with flowers. They are usually interpreted as defensive structure and are often produced in response to attack by insect herbivores. They attract insects, primarily ants, which defend the nectaries, thus protecting the plant against herbivores.