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How do Venus fly trap digest insects and does it matter what type of insect?
Question Date: 2015-04-29
Answer 1:

Venus fly traps and other carnivorous plants are cool, aren’t they? These plants get their energy from the sun, just like other plants. They get carbon dioxide through their leaves, just like other plants. But they live where the soil is very poor and has few nutrients. It might be a sandy area, or a bog where the water is acidic and dead stuff doesn’t break down.

Plants need nutrients to make their own cells. Carnivorous plants get some of theirs by trapping and breaking down insects for the nutrients in their bodies. It doesn’t really matter what kind of insect because all are made from the same basic building blocks (nutrients).

The plants use chemicals called enzymes to break down the unlucky bugs. There are countless enzymes in living things. Some build chemicals up. Others break chemicals down. The carnivorous plants use enzymes like the ones in your digestive system to break down their prey. Then they absorb the nutrients (such as nitrogen) and use them to make their own proteins. Some of these proteins will be the digestive enzymes that help to dissolve the next unlucky insect.

It doesn’t matter to the plant who gets dissolved, but what makes the Venus flytrap more likely to catch flies than ants? Do you think there are many carnivorous plants that have insect pollinators?

If these sorts of questions interest you, you may have a future in plant ecology.

Thanks for asking,

Answer 2:

They digest insects by trapping them inside of modified leaves and then secreting digestive enzymes. They digest insects because they need the sulfur, nitrogen, and phosphorous in the insects' bodies; the plant can get everything else it needs from the air (and the sun).

Answer 3:

Once the trap closes completely, it forms a seal along the edges and the surface of the leaf then secretes a variety of digestive enzymes to break down as many macromolecules as possible (these include proteases for proteins, and nucleases for DNA/RNA - essentially the plant needs what plants usually get from the soil, including nitrogen, phosphorous, sulfur, and other trace elements). The secretions fill up the space inside the leaf, making it a little digestive sack. Eventually, the soluble digested nutrients are absorbed by the surface of the leaf, and the leaf re-opens, leaving only the indigestible exoskeleton behind. Different bugs have different amounts of digestible and indigestible material. Speaking from experience, something like a worm will be entirely digested, while an isopod (aka a pill bug or "roly poly" ) will leave behind it's entire exoskeleton although it will be hollow (all the tissue inside is dissolved) and slightly bleached looking, so some of the pigment must also be digestible. I Hope that answers your question!

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