Holy crap, that's cool. An entire new kind
It's a monocot, too! The bromeliads have company! Must be really unrelated to any other known carnivore.
The actual journal article (https://www.pnas.org/content/118/33/e2022724118
) seems to be paywalled, but I happen to have university access to PNAS. Some highlights:
- The plant is Triantha occidentalis, aka false asphodel, which grows in wetlands on the west coast of North America and has sticky hairs on the flower stems.
- A previous group found that T. occidentalis had a deletion in the chloroplast gene NADH dehydrogenase-like (NDH-1), which I'm not familiar with but apparently some other carnivores have that deletion. So this group decided to test it for carnivory.
- They fed some fruit flies with radioactively labeled nitrogen, put them on the stems, and then measured the amount of labeled nitrogen in the plant 1-2 weeks later. As controls, they did the same with Drosera rotundifolia and a non-carnivore.
- The Triantha stems and the sundew leaves both absorbed similar amounts of labeled nitrogen, while the non-carnivore didn't absorb any. Very solid evidence of carnivory there! It can definitely absorb nitrogen from insects trapped on the stems.
- The nitrogen seems to get exported out of the stems after a while. They suspect some is going to the fruits and some is getting stored in the roots/leaves/etc.
- Based on some calculations, they estimate that 64% of the nitrogen in the leaves is from insects eaten in previous years. They say this might be overestimating a bit, but either way it's pretty close to D. rotundifolia's 76%.
- They also showed that the stems are producing digestive enzymes (specifically some kind of phosphatase) using a chemical that glows when digested by phosphatases. This makes Triantha the first monocot that's ever been proven to both trap and digest prey all by itself - the bromeliads use microbes and insects to break theirs down.
- It's also the first time a carnivorous plant has ever been known to eat solely through the flower stalk, which raises all sorts of questions about nutrient storage and pollination. The plant is pollinated by bees/butterflies but doesn't seem to trap them, so either it's only sticky enough to trap smaller insects or the stem is only attractive to smaller insects or both.
- There are three other species in the genus Triantha, and at least one of them (T. glutinosa) has been seen with insects stuck to the flower stalks. Could be more carnivores on the way!
- They close by pointing out that it's especially cool that this plant is fairly common near some major cities, and we just now realized it's carnivorous! How many other carnivores are hiding right under our noses??
I feel like the next step is gonna be making sure that people collect it responsibly, because I could see it becoming a lot less common in a hurry from poaching... : (