^{(Photograph = Opuntia megasperma var megasperma, wildlifetravel.com)}

Introduction

The Galapagos Islands are far from the mainland of South America. At some time in the distant past, iguanas, birds, Opuntia, and other organisms made their way there and diverged over time into new species not found on the mainland.

The Details

It depends how you count them, but there are at least four species of Opuntia on the Galapagos Islands, each with several varieties. The four species are O. echios, O. gigantea, O. helleri, and O. megasperma. Overall, there are about 12 varieties on the islands. The various varieties are found on one of a few islands each, but no species or variety is found over the whole chain.

The Opuntia species are part of the islands’ food chain feeding birds, iguanas, tortoises, and many insects. The Opuntia  are especially important because they provide cladodes, fruit, and seeds during dry times when other food is limited.

Opuntia on islands with long-necked tortoises are tall and have no lower cladodes, maybe because they have all been eaten. In corollary, short Opuntia are found on islands with no tortoises.

Related Reading: Exploitation of Opuntia Cactus by Birds on the Galapagos

Who Eats Opuntia

Opuntia megasperma, Herpetologist

Opuntia species with immature fruit, Andy Jones

Opuntia Flower, Sally Taylor

Opuntia echios var. barringtonensis, Jason Hollinger

Opuntia echios var zacana, Haplochromis

Opuntia megasperma var megasperma, wildlifetravel.com