Scybalium fungiforme is a little-known fungus-like plant species of the family Balanophoraceae. It has bunches of tiny pale flowers that are surrounded and housed by a hard surface of bracts. Because of their scale-like shape, the bracts must be opened or peeled back to expose the flowers and nectar to pollinators such as bees. While most Balanophoraceae species are primarily pollinated by bees and wasps, São Paulo State University researchers hypothesized something different.
In the early 1990s, São Paulo State University’s Professor Patrícia Morellato first made the prediction that opossums, with their opposable thumbs, would be a key pollinator for Scybalium fungiforme due to the challenging bracts covering the flowers.
Professor Morellato and her colleagues studied the plant and once spotted an opossum with nectar on its nose. The observations went unpublished because they did not record or obtain direct evidence of the opossums pollinating the flowers.
São Paulo State University’s Dr. Felipe Amorim did not encounter the plant until 2017, but hypothesized that a non-flying mammal is needed for pollination based on the flower morphology. His students independently hypothesized that rodents could act as the main pollinators of this species.
“At that time, neither of us knew anything about the unpublished observations made by Professor Morellato in the 1990s,” Dr. Amorim said.
In May 2019, the researchers went to Serra do Japi Biological Reserve in Brazil and set up night-vision cameras to record the activity of nocturnal flower visitors.
The cameras captured opossums removing bracts from Scybalium fungiforme and pushing their faces into the flowers to eat the nectar. It was the first direct evidence of opossums pollinating the plant.
“We sent Professor Morellato the footage. When she watched the videos, she sent me a voice message as excited as we were when we first saw the opossum visiting the flowers, because it was the first time she saw something she predicted two and a half-decades ago,” Dr. Amorim said.
A violet-capped Woodnymph hummingbird visits the inflorescence. Image credit: Felipe Amorim.
The researchers had made the opossum prediction based on ‘pollination syndrome’ — the concept that floral attributes such as color, morphology, scent, and size reflect the adaptation of a plant species to pollination by a certain group of animals.
Opossums are capable of peeling back the scale-like leafs covering the flowers of Scybalium fungiforme.
The plant does have other floral visitors that act as secondary pollinators once the bracts are removed — bees and wasps dominate the crowd, but a surprising additional visitor was several hummingbirds.
“Based on the flower morphology, we could safely predict that this plant should be pollinated by non-flying mammals, but the occurrence of hummingbirds coming to the ground to visit these flowers was something completely unexpected to me,” Dr. Amorim said.
The team’s work was published in the journal Ecology.
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Felipe W. Amorim et al. Good heavens what animal can pollinate it? A fungus-like holoparasitic plant potentially pollinated by opossums. Ecology, published online February 11, 2020; doi: 10.1002/ecy.3001
