why insectivorous eat insects

Why Do Insectivorous Plants Eat Insects? (11 Examples)


Insectivorous plants are plants like any other, except that in addition to being able to synthesize organic matter from water, carbon dioxide, minerals, and light, they can, like animals, take advantage of the organic matter provided by a prey.


You are probably wondering why insectivorous plants eat insects? Well, it’s actually quite simple: Plants need nitrogen, however, these plants have developed in nitrogen-poor regions.


Since these plants cannot assimilate nitrogen through their roots, because there is very little of it, they are forced to get it from their prey.


Why do some plants feed on insects?

Most green plants can only assimilate nitrogen through their roots, and in the form of nitric ion, possibly nitrous ion or ammonia. It is then, in the plant, that this nitric nitrogen is reduced to ammoniacal nitrogen, (NH4+), then incorporated in the form of amino acids.


Insectivorous plants, on the other hand, are adapted to life in regions poor in assimilable nitrogen. Their means of survival: organic nitrogen, from a prey. Most often, it is a small insect, which will be either drowned in an urn, or held prisoner between two parts of leaf.


However, once trapped, and whatever the capture technique, the insect must be transformed into assimilable nitrogen. This is why it must be digested. Digesting prey means cutting them into “bricks” small enough to enter the cells.


In this, the process is the same as that which governs human digestion. Unlike animals, however, an insectivorous plant does not have a digestive system.


How do insectivorous plants digest insects?

Little by little, the prey is cut into tiny pieces, the amino acids, which are easily absorbed by the plant. After a few hours, the amino acids circulate in the leaves in vessels called xylem. They then pass in the stem and go down to the roots.


Two to three weeks will be necessary for complete digestion. Finally, almost complete: in the trap, there is still a desiccated carapace. Indeed, insectivorous plants do not have enzymes capable of digesting the insects’ exoskeleton.


What insects do insectivorous plants eat ?

Most insectivorous plants eat only small prey. The majority of insectivorous plants are called “insectivores”.


The famous Dionaea muscupula eats flies, butterflies, and other flying insects that come within its reach. Plants of the genus Genlisea feed on protozoa, the micro-organisms present in water.


Crustaceans, slugs, worms… the preys are varied. And depending on the size of the trap, some insectivorous plants can even eat amphibians such as frogs, newts… or even small mammals, such as rats or mice! This is the case of the swollen nepenthes, nepenthes rajah, to which the name “insectivorous plant” is perfectly appropriate.


How do insectivorous plants trap insects?

Insectivorous plants are varieties of plants that trap small insects, such as mites, insects and small slugs. They are distinguished by their different trapping techniques.


Some insectivorous plants move more or less, and these movements are more or less rapid. Thus, there are active traps, semi-active traps and passive traps.

The active traps: these plants have a more or less rapid movement of closing leaves on their prey.


Semi-active traps: these plants have slow movements, from a few minutes to a few hours.

Passive traps: the plants are completely immobile, they capture their prey without making any movement.


Why are some plants insectivorous?

Peat bogs, sandy soils, marshes: in acid soils, poor in bacteria and oxygen, the decomposition and mineralization of plants is slowed down. The soil is then poor in major nutrients such as nitrogen, potassium and phosphorus.


Faced with this lack, some plants have set up a form of “parallel” feeding, to complete their supply of nutritive elements. An insect represents a significant contribution in macroelements as well as in trace elements: the plant will then be able to assimilate the nutrient that it lacks, to leave aside what does not interest it.


11 plants that eat insects

1. The Dionée flycatcher

The Dionea is a famous insectivorous plant that can easily be found in plant shops. It consumes flies, butterflies and other flying insects. 


2. Drosera

Drosera attracts insects on its sticky hairs.  


3. The Sarracenia

The Sarracenia has urns in which insects fall and are digested. 


4. The Sarracenia

The plant produces an odor that attracts insects. They land on the leaves and get stuck. Then the leaf wraps around them very slowly.


5. Pinguicula

The plant produces an odor that attracts insects. They land on the leaves and get stuck. Then, the leaf wraps around them very slowly.


6. The Nepenthe

The Nepenthe looks like an urn. The prey falls in and is killed by the digestive liquid.


7. Drosophyllum

The Drosophyllum works like a flypaper, the insects remain attached to it.


8. Cephalotus

The Cephalotus works with a trap in the shape of an urn, the insects fall in. 


9. The Cephalotus

The Cephalotus works with a trap in the shape of an urn, the insects fall in. 


10. Utricularia

This insectivorous plant eats prey thanks to the utricles. These small “bags” suck the small insects as soon as it touches the sensitive hairs.


11. Heliamphora

From the Sarracenia family, this insectivorous plant works exactly the same way. Its funny urn-shaped leaves allow it to feed on insects.

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