The glass slipper of the greenhouse: what is the cost of the orchid trade?

Slipper orchids, despite being threatened in the wild, can be found in greenhouses all around the world © iStock

By |2022-06-21T14:36:02+00:00May 5th, 2022|Asian Species, Captive Breeding, Orchid Specialist Group, Plants, Southeast Asia|Comments Off on The glass slipper of the greenhouse: what is the cost of the orchid trade?

The protection of endangered plants is often overlooked in the world of conservation. But not only is the conservation of plant species vital for overall ecosystem survival, there are also specific threats facing plant species which need to be tackled and protecting them is a far more fascinating endeavour than you might expect. Anna Heath describes the evolutionary tricks which make orchids so striking and how the orchid trade is threatening the future of a particularly rare group: the slipper orchids.

When you think of an endangered species in Southeast Asia, what do you think of? For most people, this is probably an orangutan or an elephant, perhaps a pangolin.

The vast majority of people would not think of an orchid, even though there are 124 species of orchid in South and Southeast Asia currently listed as Endangered or Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.

A striking orchid with white and pink petals in a green setting

This beautiful bamboo orchid often grows in the same place as the much rarer Paphiopedilum agusii orchid, so perhaps this noticeable species can be used as an indicator to identify the more elusive and less vibrant species. Image © Destario Metusala

Orchids: A diversity of trickery

Orchids are the world’s most diverse group of flowering plants, and it is estimated there are over 27,000 species of orchids. But did you know that some species use trickery to entice pollinators?

Unlike most other flowering plants, which produce nectar to lure pollinators to them, many orchids instead rely on deception to attract their pollinators. The bee orchid, for example, takes advantage of male bees looking for a mate. Unwitting male bees scouting for females are enticed by a female bee scent and a large petal that has evolved to resemble a female of a specific species of bee sitting on a flower (it is even hairy!). While the male bee believes he is having a successful encounter with a female bee, the orchid sneakily dumps pollen onto his back, which is transferred to another bee orchid if he is foolish enough to be tricked twice.

A furry brown bee is faux-copulating with the furry brown petal of an orchid with otherwise pink petals (there is another flower next to it where we can see the brown furry petal properly but it does not look very bee like...)

Eucera bee fooled by a bee orchid (Ophrys tenthredinifera). Image: Ferran Pestaña CC BY-SA 2.0

Another group of orchids known as slipper orchids has favoured food deception over sexual deception. They rely on deceit combined with a clever bit of structural design to attract their pollinators of choice – hoverflies. Many species in this group have spots resembling aphids, which is a specific lure for pregnant hoverflies that like to lay their eggs in aphid colonies. Once the hoverflies have been lured in, they fall into a slipper-like pouch under the fake aphids. From here, they are only able to escape via a carefully structured tunnel that forces them to rub their bodies along specific parts of the orchid – the parts which distribute and collect pollen.

An orchid with one large green petal with long dark stripes going upwards and two thinner green petals growing outwards with little dark spots. Underneath the centre of the flower is a brown receptacle-shaped petal or 'slipper'.

The Java slipper orchid Paphiopedilum javanicum. Image © Orchid Specialist Group

These intricate relationships (fraudulent as they are) with their pollinators add to why orchids are so vulnerable. If an orchid is reliant on just one species of insect to pollinate it, anything that affects the population of that insect will also impact the orchid.

This level of specialisation is also what leads to the high variety of beautiful flowers associated with orchids. This is what makes them so attractive to collectors for the plant trade – a key driver of their decline, particularly in Southeast Asia.

Unfortunately, the slipper orchids mentioned above are one of the groups that is in great demand and are amongst the most threatened wild orchids on Earth. IUCN Red List assessments of this group show that most of them are threatened with extinction.

Filling in knowledge gaps

Concerned by the plight of Southeast Asian slipper orchids, and as part of its mission is to support conservation for overlooked and underfunded species, Synchronicity Earth supported the IUCN Orchid Specialist Group to carry out a baseline study to find out more about the level of threat faced by slipper orchids.

The study focused on the orchid tra