How did carnivorous plants evolve?
We know these botanical meat-munchers evolved to make the most of a low-nutrient niche. But how they got there is a different question. Most plants don’t produce digestive enzymes, so where did carnivorous plants get theirs?
There’s not a single, definitive answer to this. But at least some of the origins of plant carnivory are probably rooted in plant defense, said Rice. Those digestive enzymes may have begun as compounds meant to ward off insects.
In another example, Rice explained that the sticky, glue-trap hairs that are all over sundews could’ve once been something like the gummy, protective hairs that cover tomato stems.
Modern pitcher plants may have been preceded by an ancestor that simply had slightly cupped leaves, which helped it retain water or capture nutrients. Thus, what originated as an incidental trait variation became advantageous and selected for.
Recent research has only just begun to trace the origins of the genes that encode for plant carnivory. In one example, scientists determined that the prey absorption genes in the modified leaves of Venus flytraps and sundews are derived from DNA that would normally be expressed in a plants’ roots, according to a 2020 study published in Current Biology.
What’s clear is that it’s not that hard for plants to turn into meat eaters. Carnivory is thought to have emerged at least 11 times in different lineages across plant evolutionary history, said Rice.
