Well known from the products made from their milky sap, the rubber trees that dot the floodplain forest provide an important source of food to fishes and other animals during the annual floods. During the daily few hours of hot sunlight in the rainy season, the rubber tree's seed capsules mature and explode, sending the seeds flying into the water. Then, throughout the high-water season, the floating seeds are gobbled up by animals capable of cracking or crushing the hard exterior, including large fishes foraging in the flooded forest, and birds and monkeys, which scoop the seeds out of the water. Black piranhas split the seed shells with their razor sharp teeth to eat the kernel inside. Because they digest the seeds, these animals do not act as dispersers.

Seeds that are not eaten can be carried long distances by the flood-waters. and they germinate when the floods recede. Tambaqui love rubber tree seeds so much that they will tear up seedlings to eat the remainder of the nut. Despite all the predation, rubber trees still are among the most common trees in the floodplain forest.

In the 1870's people began harvesting the sap from these trees to make rubber. This caused the Iquitos area of the Amazon basin to grow from 1500 people to nearly 24,000 within a decade. For the next 30 years, Iquitos was at once an area of great wealth and great poverty. The rubber barons became quite wealthy while the local rubber tappers were quite poor. This boom lasted until people began cultivating rubber trees in the Malay Peninsula.