In the summer of 1989, Jack Dumbaher was a fresh person an ornithologist training at his maiden expedition to the lush tropical forests of Papua New Guinea. One sticky in the afternoon, he noticed an unusual bird with nasty black and orange feathers entangled in his fog. But while Dumbacher tried to release him, the hood of Pitohui scratched him.
“They are birds the size of a Jay with sharp nail and bills needle,” says Dumbaher, who instinctively put a cut on his lips. “My mouth began to tingle and burn, and then shuddered, continued until night.”
When Dumbacher consulted with his local guides, they nodded consciously, telling him how the peasants would avoid the “garbage birds”, eating them only if they were “leather and specially prepared”. Curiosity Piqued, a then student at the University of Chicago, spent next year collecting Pitohui samples and looking for a chemist at home that could determine the source of special sensations.
In 1992, Dumbacher and his associates announced their amazing discoveries: a hood of Pitohuis carrying Batrotoxin. The toxin is more rammed than cyanide and is one of the most domestic substances in the animal kingdom. It is the same substance found in certain poisonous frogs in the middle of the world.
Since then, at least a dozen other bird species, out of more than 10,500 known to science, have been identified as toxic. Some members of this selected group – such as European quail, North American rude and European hoops – have been found outside New Guinea and contain various toxins. The majority, however, are batrotoxin and endemic for the world’s second largest island, including at least five other Pitohui species and blue limited IFRIT.
But at the age of 35, Dumbacher’s Serendipitis Discovery, a very mystery to the poisonous birds of New Guinea. “There is a tone that we do not know – from the bird’s environment to how they use Batrotoxin for defense and where they get it,” says Dubacher, now the California curator of the California Academy of Bird and Mammal Sciences.
He last visited the island in 2011 and another team of scientists – led by the environmentalist Knud Yonson of the Swedish Museum of Natural History and Biologist of Evolution and Community Casun Bodivat at the University of Copenhagen – the studies of Dumbacher continue. They have already made entry, identifying two new species for toxic birds in 2023, the first discovery of nearly two decades. They plan to visit Papua New Guinea annually until 2028.
They hope to answer a key question: where does the toxin – report to protect birds from predators and parasites – originated from?
You are what you eat
One theory of the origin of this poison is the bird’s diet.
“It is chosen that they eat these custine beetles and so they get their toxin,” says Jonson. “But in reality we don’t know.”
Dumbacher-which in 2004 is the first to describe how Batrotoxin is present in both birds and beetles-does not believe that toxin comes from tiny insects of rice size.
“The bigger part of the information suggests that beetles cannot produce such steroid alkaloids,” he says. “So it is very possible for beetles to receive it from another source like soil mites or even a plant.”
In order to track the origin of Batrotoxin, researchers plan to collect poisonous birds and compare the contents of their stomach with insects caught in the nearby traps. “The idea is to try to home for potential elements of prey that have a toxin,” explains Jønsson. “A lot is looking for a needle in hay, but this is the first step we can do.”
They have also partnered with Christine Bielmans, a chemist at the German University of Saarland, to determine Batrotoxin and molecularly similar toxins in the samples already collected.
Tests show that poisonous birds contain a mixture of toxic derivatives – the Beemelmanns laboratory has identified six so far – which can vary in concentration between individuals and species.
Pitohui with a hood is one of several poisonous birds that are documented in Papua New Guinea. While poisonous birds are documented in North America and Europe, the majority known in science is found in this region of the South Pacific. Photos of Knud Jønsson
How do birds remain immunized?
Another lasting mystery is how birds protect themselves from the deadly toxin they carry.
Batrotoxin binds to sodium ion channels in the nerves, muscles and heart cells, leading to numbness, convulsions, paralysis and even death. “He sits on these channels and keeps them open so that the nerves just continue to tremble,” says Jonson.
Poison birds contain far less toxin than the golden poisonous frog that carries enough Batrotoxin to kill 10 grown men. Pitohui with hood – the most toxic bird species – are not deadly when processed or consumed.
The long -standing theory that explains how birds are “not killing” is that they, like the frogs of poisons, contain mutations in their sodium channels, which do not allow the toxin to connect, says Daniel Minor, a biophysicist at the University of California, San Francisco, who does not participate in John and the underlying research.
The same feature is found in Fugu fluff, octopus with blue rings and other poisonous animals that remain impenetrable to the toxins they carry.
In fact, when Jonson and his associates compare the genomes of six toxic bird species to their non -toxic cousins in the same families, they found that poisonous birds contain multiple mutations in a gene encoding a specific sodium channel.
However, when the MINOR team conducted electrophysiological tests on genes cloned by the southern variable Pitohui in a separate set of experiments, they were “distracted” to find that sodium channels remain sensitive to batrotoxin – they create their mutations.
Minor now believes that bird resistance lies in a still unidentified protein, which acts as a “toxin sponge” binding to Batrototoxin and sequent. The work of he and his colleagues on Saxitoxin, another protein that binds to sodium channels, has provided this insight.
“Our laboratory has shown that a socyphylline, a protein, naturally found in toad of poisonous arrows, can be inserted and binding to high affinity with Saxitoxin,” he explains. “So maybe it’s the same for Batroxin.”
Jønsson and Bodawatta believe the two mechanisms can be complementary. “Birds, anyway, have to transport batrotoxin from intestines to skin,” said prickly. “So they have to have a transport protein that makes it easier.”
Is there more?
Scientists are willing to know if there are more toxic birds.
Jønsson thinks it’s very likely. “The poisonous birds of New Guinea belong to Corvides Super Family of Birds that contain approximately 700 species worldwide,” he says. New Guinea is home to 140 of them, and his team has so far studied only one fifth of them.
From this November, his team will collect “as many Corvides samples” from different parts of the island and screen them for Batrotoxin. They also plan to consistently as a little individual species to identify mutations of sodium channels.
A more comprehensive genome set of data will also allow scientists to identify possible toxin fungal proteins, adds Bodawatta.
The broader, the researchers want to study the “super cool and crazy convergent evolution”, which is allowed for this special resistance to toxins in both frogs and birds, as well as unrelated bird species in New Guinea and other places around the world, says Bodavata.
“Understanding convergent natural selection adaptations is a central goal of evolutionary biology,” Yonson adds.
The more scientists they learn what exists, the more questions they will be able to ask why they do it.
“Maybe in two to three years we will have some new sharing insights,” Bodawatt says. “This is just the beginning.”