Inga / Ice-cream Bean

Overview

Inga edulis — known in Costa Rica as guabillo, cuajiniquil, or ice-cream bean — is one of the most ecologically important trees in Tortuguero’s understory. A fast-growing member of the legume family (Fabaceae), it fixes atmospheric nitrogen through a symbiosis with Bradyrhizobium bacteria in root nodules, enriching soils and accelerating forest succession on disturbed ground. The genus Inga — with over 300 species — is one of the most species-rich tree genera in lowland Neotropical forests, and several species in the complex are common throughout Tortuguero.

The tree produces long seed pods (20–100 cm) containing seeds embedded in a white, cottony, sweet pulp — hence the English name “ice-cream bean.” The pulp is edible and widely consumed by people and wildlife alike: monkeys, bats, rodents, toucans, and tanagers all exploit the fruit. Extrafloral nectaries on leaf stems attract ants that defend the tree against herbivores in a mutualistic arrangement documented throughout the genus.

Why Tortuguero

In a park defined by its canals, the canal-edge vegetation is the zone most visitors actually see from a boat. Inga species are among the most common canal-margin trees in Tortuguero — their spreading crowns overhang the water, their flowers attract pollinating bats and hummingbirds at night and day respectively, and their fruiting pods bring in a diverse parade of birds. A flowering Inga tree along a canal is worth a slow stop: the succession of visitors (crowned woodnymph, rufous-tailed hummingbird, collared aracari, spider monkey) is often better than anything downstream.

Nitrogen fixation also means Inga plays a structural role in maintaining the fertility of Tortuguero’s leached, waterlogged soils — a function that is less photogenic than the fruit display but just as important for the forest community.

How to see them (honestly)

• Inga trees are common along every canal in the park; identification at a distance rests on the characteristic feathery compound leaves with a winged rachis between leaflets.
• Fruiting pods — long, green, and cylindrical — hang visibly from branches when ripe.
• To identify I. edulis vs. other Inga spp., look for the very long pod (often > 40 cm) and the winged petiole axis between leaflet pairs.
• A flowering Inga at any hour is worth watching from the boat for 5–10 minutes: hummingbirds are predictable, bats come at dusk.

Status note

Inga edulis is Least Concern globally — it is widespread, adaptable, and widely planted for shade, soil improvement, and fruit in agroforestry systems from Mesoamerica to Amazonia. In Tortuguero, the species and its congeners face no direct threat within the park. The principal concern for Inga ecology in the region is upstream deforestation and agricultural intensification, which reduces the nutrient-fixing forest cover that stabilises the watershed feeding Tortuguero’s canal system.