Carnivorous plants are known for a steady diet of creepy crawlers, mostly small insects and spiders. But according to a new study, they’ll also savor a bigger, juicier meal should the opportunity arise.
Scientists in Canada recently discovered a pitcher plant that feeds on baby salamanders—drowning the amphibians in a special brew of acidic fluid, and slowly digesting their flesh. This marks the first documentation of salamander-eating plants in North America in modern scientific literature, the new study published in Ecology last week noted.
The discovery happened last year when ecologists were surveying Ontario’s Algonquin Provincial Park, a protected natural space that hosts a wildlife research station.
Alex Smith, an integrative biologist at the University of Guelph, was exploring “the wonderful world of bogs” with a group of undergraduate students and happened upon a pitcher plant—specifically the purple pitcher plant, or Sarracenia purpurea—containing a young salamander, Smith said in an email.
He shared this news with Patrick Moldowan, a PhD candidate at the University of Toronto’s Department of Ecology & Evolutionary Biology, who told Smith that in 2017 a student had also found S. purpurea feeding on a salamander.
“There is a conspicuous absence of vertebrate prey” in scientific records about the plant’s diet, the study notes. “More work needed to be done,” Smith said.
Over the course of 2018, Smith and Moldowan, along with four other colleagues, conducted several surveys of S. purpurea at an amphibian-rich bog in Algonquin Provincial Park.
Two efforts in late 2018 revealed that 132 plants held a total of 34 salamanders, representing roughly 20 percent of the plants surveyed. This was enough to categorize pitcher plants as a “considerable mortality source for young salamanders,” according to the study.
The prey species was always the yellow-spotted salamander, or Ambystoma maculatum, which breeds in the area.
It’s not clear whether the salamanders crawled or fell into the pitchers. But the study theorizes that some escaped their leafy tombs by being flushed out with rainwater.
The unlucky ones decomposed quickly, the study adds. “Instances of foul odor” were sometimes observed, “suggesting prey overloading and putrefaction.”
Carnivorous plants often occur in locations with poor soil, like bogs, and must derive energy from other, meatier sources. S. purpurea uses digestive enzymes and symbiotic bacteria to dissolve prey into nutrients such as nitrogen. According to the study, a single salamander could provide “an amount of nitrogen equivalent to that contained in three pitchers.”
Smith believes that pitcher plants may be eating salamanders more often than we know, but documentation is challenging partly due to their swift rate of decay.
“This study and survey are only the beginning,” he said.