Australia’s Newest Deadly Creature: The Giant Stinging Tree

Most people are aware of the unique wildlife that inhabits Australia, from its adorable kangaroos and koalas to some of the world’s most venomous snakes and spiders. But recently, scientists have delved deeper into the secrets of what, upon first glance, looks like a harmless plant in the continent’s rainforests. The Australian stinging tree, also called the Gympie-Gympie tree, resembles any common shrub, even boasting welcoming, fuzzy green leaves that passersby are inclined to feel. But someone who so much as lays a finger on the plant would be injected with an extremely potent and painful toxin. In fact, what appears to be fuzz on the tree’s leaves is actually an array of poisonous needles ready to fire at the first touch. Centuries-old legends describe men being driven to insanity and horses jumping off cliffs after a prick of the tree’s needles. Reportedly, the toxin can remain in the body for several days, even months.

A Gympie-Gympie sting initially feels like fire, then after a few hours, transitions to a searing and aching pain. And a final stage—allodynia—lasts for days after the sting, during which seemingly innocent activities like taking a shower reignites the pain.” In recent years, the Australian stinging tree has even been nicknamed “the suicide plant,” as no form of treatment is currently known to ease the pain. However, biologists led by Dr. Edward Gilding from the University of Queensland are hoping to study Gympie-Gympie toxins to develop a better understanding of the mechanisms by which they act, ultimately aiming to improve remedies. Through various experiments, the scientists analyzed the needle-like hairs of the plant, called trichomes. Prior research had indicated that the molecule called moroidin may have been causing the pain; however, in subsequent experiments, this theory was disproved. Later analyses of the genes in the stinging tree, as well as separation and synthesis of the components of the tree’s toxin, uncovered neurotoxins named gympietides.

Gympietides have been found to overload pain receptor cells, causing them to lose control in the production of pain-inducing signals. These signals are created by a stimulus that causes pain, which then induces electrical impulses that travel from neurons to the brain to indicate damage to body tissues. The toxin acts by latching onto these cells, stopping them from reverting to their original state. Because the gympietides have a stable structure, they can remain in the body for long periods without being broken down. The gympietides are also able to resist strong painkillers like morphine through suppression of bodily mechanisms that attempt to stop pain. By affecting ion channels in nerve cells, gympietides prevent them from closing like usual, causing the cell to be unable to stop the continuous pain. As stated in The Guardian, “The Australian stinging trees make a neurotoxin that resembles a venom in both its molecular structure and how it is deployed by injection.”

At the moment, scientists are still unsure of the best way to treat a Gympie-Gympie tree’s stings. Thus, they are working with environmentalists to put up warning signs around these trees. The signs inform passerby of the dangerous toxins these trees possess. As said in The New York Times, in the case of an accidental run-in with the stinging-tree, people who frequent these forests are arming themselves with respiratory protection, heavy-duty gloves, and fistfuls of antihistamines. While Dr. Gilding’s research sheds new light on the Australian giant stinging tree, it still has not uncovered all its secrets. For example, the team is unsure of the function of its toxin. While they theorize it was used to help dissuade herbivores from eating the plant, animals such as beetles and pademelons often consume the plant, spines included. In addition, the researchers suspect that gympietides are not the only contributing factor to the toxin’s potent and lasting sting, as well as its other symptoms such as chest pain and discomfort in extremities.

Dr. Gilding and his team’s research has barely scratched the surface of the Australian giant stinging tree’s mysteries and what makes its toxin so painful. They hold high hopes that their research will propel other research projects on gympietide antidotes. "By understanding how this toxin works, we hope to provide better treatment to those who have been stung by the plant, to ease or eliminate the pain," said Dr. Vetter, a pain researcher collaborating with Dr. Gilding.

Studying the toxins produced by venomous organisms may at first seem fruitless compared to researching climate change or searching for cancer treatments. However, it brings us closer to the biodiversity of our planet as we continue learning about the unique defense mechanisms organisms use to live through each day. Furthermore, it has the potential to help us further understand the pain and its causes, which in turn will allow for the development of more pain-relieving treatments in the near future.