A plant that grows in bogs along the west coast of North America has been spotted using its flowers to eat insects. Until now, researchers had no idea it was carnivorous.
Carnivorous plants absorb nutrients from insects and sometimes vertebrates. Before now, there were 11 known groups of such plants, with the last being described in 2012.
Now, Qianshi Lin and her colleagues at the University of British Columbia in Canada have demonstrated that a small flowering plant called Triantha occidentalis is also a meat-eater.
“It is not just another species of known carnivorous plants,” says Lin. “This is a totally new group of carnivorous plants.”
The researchers decided to look at T. occidentalis after previous research found the plant had lost genes that were also missing in carnivorous plants. They examined the concentration of nitrogen within the plant and found it comparable to carnivorous plants, suggesting it could be acquiring the nitrogen from insects.
To find out more, the researchers placed fruit flies that had been fed nitrogen-15 isotopes onto the clustered flowers on the plant’s stems, which are known as inflorescences. They later found this isotope inside the plant at higher concentrations than before the fruit flies were introduced, which indicated that it had consumed the fruit flies.
“Somewhat unique is that they capture insects with inflorescences,” says Gerhard Gebauer at the University of Bayreuth in Germany. “Most carnivorous plants capture insects with their leaves so this is unexpected in a certain way.”
Gebauer had previously suspected that plants within Triantha are carnivorous after observing that the nitrogen concentrations of Tofieldia calyculata, a plant in that family found in the Austrian Alps, were different to those of non-carnivorous plants in the region.
“Nobody else before has expected carnivorous plants in this taxonomic group, except for [Tofieldia calyculata],” says Gebauer.
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