#protocarnivory

[cedar-glade]

Silene virginica

Along a rocky road cut in an open woodland near Falmuth KY on our way back from a job.

Virginia Catch fly, more of a woodland/sav species compared to the largest species known as Royal catch fly. I also feel like this species is much more common overall. The common name “catch fly” refers to it’s ability to trap small flys and other small insects along it’s entire stem, the largest glands are associated with the sepals and they have more glands the higher you go. The glands on royal catchfly tend to trap more insects overall in compared to any other species. Royal Catch Fly was even considered to be a potential species to be monitored for protocarnivory; however, the glands that are present do not exude protease nor do they have similar enzyme groups that could potentially systematically break down proteins or aid in overall digestion. The sites that these species live in tend to have very nutrient rich or complex soils as well which may mean that the biological and abiotic pressures involved to evolve these characteristics are not present to force such needs over evolutionary time. There could always be a development in some populations of Silene spp. that could occur over an extended time and this family, Caryophyllaceae, is known for carnivory.

With all that said the glands on these plants do act as stabilizers to keep these plants erect and upright.

[regnum-plantae]

Neoregelia kautskyi, Bromeliaceae

Pretty much anybody is familiar with what a pineapple fruit (Ananas comosus) looks like, and various species of Tillandsia, Bilbergia and Guzmania are now common houseplants, but there’s so much more diversity of shapes and adaptations within the Bromeliaceae to appreciate. The Neoregelia species in the photos, first scientifically described in the early ‘70s, is endemic to eastern Brasil and part of a genus of very showy and peculiar plants, commonly known as the ‘blushing bromeliads’, often hybridised to enhance their striking colour patterns. However, more than its coloration, which is probably an adaptation to attract pollinators, it’s what goes on at the center of the plant which surely catches the eye. Like many other species within the family, this Neoregelia forms a tight cup with its leaves which stores rainwater and effectively creates a miniature ecosystem. You can see the small three-petalled, tubular flowers (Bromeliads are monocots) emerging from the base of the inflorescence at the bottom of the ‘pond’ and I wish the numerous larvae wiggling and swimming around them were just as visible. If insect larvae are not that surprising to find there in the stagnant water, arboreal frogs and crabs are maybe more suggestive of the importance of the habitats these epiphytic plants create high in the canopy. 

But why would a plant go through the effort of evolving in this direction when water is certainly not a limiting factor in the rainforest? Well, some bromeliads are known to show a degree of protocarnivory, which means they benefit from the nitrogen and the other nutrients dissolved in the water they collect, and these nutrients come from their animal hosts in the form of droppings and unconsumed parts of their meals, but they do not actively produce digestive enzymes to speed up the process. I actually described this fascinating concept before, when writing about wild teasel (Dipsacum fullonum), a large thistle-like plant native to Eurasia which collects rainwater in its modified sessile leaves. Protocarnivory seems to be much more diffuse in the plant world than previously believed and there is still a good deal to learn, but this just shows how evolutionary pressure plays along in ways we might not even begin to imagine until we get to understand them!