A team of biologists from the Universities of Guelph and Toronto has discovered that a species of carnivorous plant called the northern pitcher plant (Sarracenia purpurea) in Ontario’s Algonquin Park wetlands consume not just bugs but also young spotted salamanders (Ambystoma maculatum).
Pitcher plants (family Sarraceniaceae) growing in wetlands across Canada have long been known to eat small creatures — mostly insects and spiders — that fall into their bell-shaped leaves and decompose in rainwater collected there.
But until now, no one had reported juvenile salamanders caught by a pitcher plant in North America.
“Pitcher plants may have become carnivorous to gain nutrients, especially nitrogen, that are lacking in nutrient-poor bog soil,” said Dr. Alex Smith, an integrative biologist at the University of Guelph.
“Other flesh-eating plants grow in nutrient-poor environments around the world. They include sundews, which use their sticky leaves to catch insects, and the Venus flytrap.”
Monitoring pitcher plants around a single pond in the Algonquin Park in 2018, Dr. Smith and colleagues found almost one in five pitcher plants contained young spotted salamanders, each about as long as a human finger. Several plants contained more than one captured salamander.
Those observations coincided with ‘pulses’ of juvenile salamanders crawling onto land after changing from their larval state in the pond.
“These bog ponds lack fish, making salamanders a key predator and prey species in food webs,” Dr. Smith said.
“Some of the animals may have fallen into the plants, perhaps attracted by insect prey. Others may have entered the plants to escape predators.”
Prey caught inside the plant’s specialized leaves is broken down by plant digestive enzymes and other organisms in the water held inside the leaf.
“This discovery opens new questions for biologists,” Dr. Smith said.
“Are salamanders an important prey source for pitcher plants? Are the plants important predators of the amphibians? Might the salamanders compete with plants for insect prey — and even ‘choke’ the plant?”
The team’s paper was published in the journal Ecology.
Patrick D. Moldowan et al. Nature’s pitfall trap: Salamanders as rich prey for carnivorous plants in a nutrient-poor northern bog ecosystem. Ecology, published online June 5, 2019; doi: 10.1002/ecy.2770