The Agouti Effect

I came across an interesting story in a book I am reading called Deep Jungle -- Journey to the heart of the rainforest. It is a tale of trees and orchids and rodents and bees.

The Brazil nut tree is one of the biggest trees in the Amazonian rainforest. Brazil nut trees have been transplanted to other areas, but they only bear nuts in the rainforest. Their success in South America is the result of both flora and fauna.

Orchids grow in the rainforest along with Brazil nut trees. Male orchid bees, which never touch Brazil nut trees, use secretions from orchids to attract females, which do touch the trees. It is the female orchid bees that pollinate the Brazil nut flowers.

Once the flowers blossom, they grow into hard pods that contain up to thirty seeds. The heavy pods fall from great heights, but the pod casings seldom break. Although many animals are attracted to Brazil nuts, they are unable to break into the pods, which would have a terminal impact on the survival of Brazil nuts. Or it would have a terminal impact if not for agoutis.

Agoutis are cat-sized rodents that resemble long-legged guinea pigs. They use their strong teeth to chisel through the pods to get to the seeds, which they then hide throughout the jungle. Some are taken by other species, many are eaten by the agoutis themselves, but enough germinate to ensure the continued existence of the Brazil nut race.

Deep Jungle -- Journey to the heart of the rainforest
Fred Pearce
Eden Project Books, London, 2005
ISBN: 1903919568