Some habits are rather difficult to give up.
Carnivory is one that I cling to although the balance has shifted from animal
remains to plant material. I have always drawn the line at eating live or
injured animals. In that regard, I’m in line with Woody Allen and don’t shuck
live oysters to wash them down with lots of alcohol.
As
I said, I’ve shifted towards obtaining more of my proteins and fats from the
plant kingdom and am anticipating enormous health benefits from the change. I
am fortunate in that I can make that choice. I can trundle off to the local
store when I’m getting hungry and fill my bag with lots of plant bits rather
than steaks.
Not
every carnivore can do that. What if you’re not mobile? Well, you just have to
sit and wait to see what’s available. Carnivorous plants are in that patient
species group, but this is not necessarily by preference. Millett et al in the New Phytologist considered the plight of sundew
plants who sit around in Swedish bogs (1, 2).
The
sundews catch flies, suck up the protein to get the nitrogen they need to grow,
prosper and set up little sundews to come after them. But is a carnivorous
lifestyle their preferred mode of living or would they prefer to be like most
other plants and let the good earth provide and not bother with trying to bring
those annoying flies to the sticky end that they truly deserve?
The
“New Phytologist” paper indicates that they would prefer to move away from
carnivory. Millett et al checked the Nitrogen levels in Swedish bogs and showed that
those that were more highly polluted with Nitrogen from modern farming
practices had sundews that were cutting back on their carnivory in favor of the
nutrition in the bog water. In the more pristine bogs, they got 57% of their
Nitrogen need from flies, but this had dropped to 22% in some bog locales that
were richer in Nitrogenous water.
However,
carnivory as a lifestyle choice may be better for the sundews in the longer
term as they have less competition in the Nitrogen poor habitats and they don’t
have big root systems to make them good competitors in Nitrogen rich bogs. In
the most Nitrogen rich bogs, they had to go back to eating more flies so that
33% of their Nitrogen came flying by.
- http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2012.04139.x/abstract
- http://www.bbc.co.uk/nature/18416601
