Why do Insectivorous plants exist?

If you find insectivorous plants strange and fascinating then this blog is for you.

What are insectivorous plants?

Insectivorous plants are those plants that derive some nutrients by trapping and consuming animals, mainly insects.

Categories of being insectivorous

There are essential two things that a plant has to do to be considered insectivorous:-

  1. Ability to take nutrients from dead prey:- a plant should have the ability to trap the prey and absorb nutrients from it. Those prey is usually insects or small vertebrates like, salamanders. It is not enough for the plant just to have defenses that can kill an animal that’s trying to snack on it. It also has to get it’s animal’s nutrients.
  2. At least have one adaption:- the plant need to have one adaption that actively lures in, catches, or digests it’s prey.

Doing at least one of these things and absorbing the nutrients for it’s benefit make it a insectivorous plant.

Plant traps

Over millions of years and across hundreds of species, plants have developed five different types of traps, most of them are from different times. And traps can be passive, if prey just fall into them and can’t escape, or active, if plant actually moves to catch its prey.

  1. Pitcher plant:- pitfall traps are the standard and passive trap used by plants like pitcher plants. Prey lands on the plants slippery surface and slides down into a pool of digestive juices.
  2. Sundews:- these are flypaper traps in which the prey become stuck in a sticky substance that is produced by the plant leaves. These traps can be passive as well as active. Sundews have sticky moving tentacles that react to contract with prey.
  3. Venus fly trap:- these are snap traps which are active, using rapid modified leave
  4. Bladderworts: they have bladder-suction. This creates little negative pressure vacuum inside their traps, which, when triggered by prey, pop open and suck the victim inside before snapping close.
  5. Lobster-pot trap:- they passive traps that force prey to move towards the plant’s digestive organ by having little inward pointing hairs that keep prey from moving backward out of the trap.
Venus fly trap
Lobster-pot trap
Pitcher plant

All of these unrelated plants have not only developed the same kinds of traps but it looks like they have also developed that same molecular mechanism for digesting their prey.

Reason of existence

It goes back to idea of convergent evolution. All these different insectivorous plants are responding to similar environmental pressure:-

  1. Found in open sunny places that have moist but nutrients – poor – acidic soil. Many of them live in bogs and fens.
  2. In these kind of habitat where nitrogen and phosphorus is not present in the soil, the plant tend to developed two kinds of leaves one for normal photosynthesis and one that are modified onto their particular type of trap.
  3. This results them to invest more in modified leaves than normal photosynthesis leaves as they have to live in a place with enough sunlight as well as to trap preys

Insectivorous plants can stop paying carnivorous temporally once they’re put in nutrients rich soil and if they don’t get enough sunlight and water.

Insectivorous plants are pretty rare and they are only found in certain kinds of habitats, they are just less likely to fossilize than other kinds of plants that are more widespread.