11 Enchanting Quirks of the Rare Ghost Orchid
7. It was long thought to rely on just one moth for pollination
giant sphinx moth, Cocytius antaeus
The giant sphinx moth (Cocytius antaeus) with its tongue extended.
Politikaner / Wikimedia Commons
The ghost orchid's pollen is hidden deep within its flowers, and so it can only be pollinated by an insect with a proboscis long enough to reach all the way inside.
For ghost orchids, the long-tongued pollinator was long ago identified as the giant sphinx moth, which is native to South and Central America but relatively rare in North America, with only occasional sightings in Florida and a few other southern U.S. states.
It's widely described as the sole pollinator of ghost orchids, thanks to its long proboscis and a lack of evidence for any other pollinators. Its larvae feed on the pond apple tree, which is also an important host for ghost orchids.
8. Its pollination might not be as simple as we thought
fig sphinx moth, Pachylia ficus
The fig sphinx moth (Pachylia ficus), pictured here on Grand Cayman island, seems to be an overlooked pollinator of ghost orchids.
Charles J. Sharp / Wikimedia Commons / CC BY-SA 4.0
Despite conventional wisdom about the ghost orchid's reliance on giant sphinx moths, photos taken in Florida suggest the reality is more complicated.
Wildlife photographer Carlton Ward Jr. set up a camera trap in Florida Panther National Wildlife Refuge, located just northwest of Big Cypress National Preserve, and caught images of five different moth species visiting ghost orchids. As National Geographic reports, two of these moths—the fig sphinx and pawpaw sphinx—had ghost orchid pollen on their heads.
This was later backed up by another photographer, Mac Stone, who captured images of a fig sphinx moth visiting a ghost orchid with the plant's pollen on its head. Both photographers also got photos of giant sphinx moths visiting ghost orchids, but none were carrying ghost-orchid pollen, raising the possibility that giant sphinx tongues are long enough to "steal" nectar from ghost orchids without actually pollinating them. These findings were published in the journal Scientific Reports.3
If the ghost orchid really does have multiple pollinators—with or without the giant sphinx—it would be welcome news, since it would mean the orchid's reproduction doesn't depend entirely on one rare insect. And that may be especially valuable now, given the threat of pesticides and other factors fueling the widespread decline of insects around the world, including many important pollinators.
9. Its habitats are becoming more hazardous
In Florida, ghost orchids tend to grow on just three tree species—pop ash, pond apple, and bald cypress—but in Cuba, they've been found growing on at least 18 different host trees.
"Although populations of D. lindenii in southern Florida and Cuba are separated by only 600 km, this species appears to occupy two different habitats and colonizes a different set of host trees," researchers noted in a study published in Botanical Journal.4
Ghost orchids in Florida also grow slightly higher off the ground than in Cuba, the authors noted, possibly because stagnant water prevents seedlings from growing on submerged tree surfaces during South Florida's rainy season.
In both countries, however, the ghost orchid's habitats "are undergoing rapid, irreversible change imposed by climate change and other factors," the researchers added. "Both regions, for example, are vulnerable to sea-level rise this century given their low elevation, and the severity and frequency of tropical cyclone activity is another concern."4
Ghost orchids have already experienced a steady decline in the wild,2 and based on simulations of habitat changes, "hurricanes and similar disturbances could result in near-certain extinction in short time horizons," researchers reported in 2015, possibly within a period of 25 years.5
The orchid faces another obstacle from encroaching human development, which is prompting changes in the water table and the fire cycle, according to a report published in the journal Wetland Science & Practice.6
Yet another threat comes from the emerald ash borer, an invasive insect that kills ash trees. It hasn't reached Florida yet, but if it infects mature stands of pop ash trees in places like Florida Panther National Wildlife Refuge—where 69% of all ghost orchids grow on pop ash—it could have a devastating effect on the species.
giant sphinx moth, Cocytius antaeus
The giant sphinx moth (Cocytius antaeus) with its tongue extended.
Politikaner / Wikimedia Commons
The ghost orchid's pollen is hidden deep within its flowers, and so it can only be pollinated by an insect with a proboscis long enough to reach all the way inside.
For ghost orchids, the long-tongued pollinator was long ago identified as the giant sphinx moth, which is native to South and Central America but relatively rare in North America, with only occasional sightings in Florida and a few other southern U.S. states.
It's widely described as the sole pollinator of ghost orchids, thanks to its long proboscis and a lack of evidence for any other pollinators. Its larvae feed on the pond apple tree, which is also an important host for ghost orchids.
8. Its pollination might not be as simple as we thought
fig sphinx moth, Pachylia ficus
The fig sphinx moth (Pachylia ficus), pictured here on Grand Cayman island, seems to be an overlooked pollinator of ghost orchids.
Charles J. Sharp / Wikimedia Commons / CC BY-SA 4.0
Despite conventional wisdom about the ghost orchid's reliance on giant sphinx moths, photos taken in Florida suggest the reality is more complicated.
Wildlife photographer Carlton Ward Jr. set up a camera trap in Florida Panther National Wildlife Refuge, located just northwest of Big Cypress National Preserve, and caught images of five different moth species visiting ghost orchids. As National Geographic reports, two of these moths—the fig sphinx and pawpaw sphinx—had ghost orchid pollen on their heads.
This was later backed up by another photographer, Mac Stone, who captured images of a fig sphinx moth visiting a ghost orchid with the plant's pollen on its head. Both photographers also got photos of giant sphinx moths visiting ghost orchids, but none were carrying ghost-orchid pollen, raising the possibility that giant sphinx tongues are long enough to "steal" nectar from ghost orchids without actually pollinating them. These findings were published in the journal Scientific Reports.3
If the ghost orchid really does have multiple pollinators—with or without the giant sphinx—it would be welcome news, since it would mean the orchid's reproduction doesn't depend entirely on one rare insect. And that may be especially valuable now, given the threat of pesticides and other factors fueling the widespread decline of insects around the world, including many important pollinators.
9. Its habitats are becoming more hazardous
In Florida, ghost orchids tend to grow on just three tree species—pop ash, pond apple, and bald cypress—but in Cuba, they've been found growing on at least 18 different host trees.
"Although populations of D. lindenii in southern Florida and Cuba are separated by only 600 km, this species appears to occupy two different habitats and colonizes a different set of host trees," researchers noted in a study published in Botanical Journal.4
Ghost orchids in Florida also grow slightly higher off the ground than in Cuba, the authors noted, possibly because stagnant water prevents seedlings from growing on submerged tree surfaces during South Florida's rainy season.
In both countries, however, the ghost orchid's habitats "are undergoing rapid, irreversible change imposed by climate change and other factors," the researchers added. "Both regions, for example, are vulnerable to sea-level rise this century given their low elevation, and the severity and frequency of tropical cyclone activity is another concern."4
Ghost orchids have already experienced a steady decline in the wild,2 and based on simulations of habitat changes, "hurricanes and similar disturbances could result in near-certain extinction in short time horizons," researchers reported in 2015, possibly within a period of 25 years.5
The orchid faces another obstacle from encroaching human development, which is prompting changes in the water table and the fire cycle, according to a report published in the journal Wetland Science & Practice.6
Yet another threat comes from the emerald ash borer, an invasive insect that kills ash trees. It hasn't reached Florida yet, but if it infects mature stands of pop ash trees in places like Florida Panther National Wildlife Refuge—where 69% of all ghost orchids grow on pop ash—it could have a devastating effect on the species.
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06 September 2023
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