Question

The Venus fly trap and pitcher plant perform photosynthesis, yet they trap insects.why?

Answer 1

because Venus fly trap and Pitcher plant belongs to the region where there is deficiency in nitrogen so they are not able to perform photosynthesis properly and are dependent on insects to gain energy.

Answer 2

Carnivorous or insectivorous plants grow in soil where the nutrient level is very low.

By performing simple photosynthesis they cannot derive these nutrients.(Especially nitrogen).

So they trap insect to derive nutrients and nitrogen from it.

So Pitcher plant and Venus fly trap derive necessary nutrients components by digesting insects

Hope it helps you!