"It turns out that 64% of the nitrogen within the plant is obtained via insect digestion"

I suspect that this is way more common than we think. This plant has sticky stems and they digest insects that stick.

It must be quite easy for plants to add insectivore to the skillset. They often already have a symbiosis with insects for reproduction. There are plenty of saps and other sticky substances available to deal with shuffling water and nutrients around. The fly trap is a bit fancy and complicated but the simple honeydew type arrangement must surely be way more common than we think it is.