Exploitation of Opuntia cactus by birds on the Galápagos

Abstract

(1) There is a close association between Opuntia helleri (cactus) and Geospiza conirostris (cactus finch) on Isla Genovesa, and between Opuntia echios and Geospiza scandens on Isla Daphne Major. The two finch species consume nectar and pollen, pollinate the obligatorily out-crossing flowers, consume the aril around the seeds, crack the seeds and occasionally disperse them.