Question

why are insectivores plants are called paritial heterotrophs

Answer 1

Insectivorous plants like Pitcher plant contains chlorophyll,hence it is capable of preparing its own food like green plants.But insectivorous plants grown in swampy and Bog areas where the soil is deficient in nitrogen mineral.So,just to fulfill the nitrogen requirements they trap insects and utilise their protiens.For this reason they are called partial heterotrophs.

Answer 2

They digest insects for fulfilling the need of nitrogen which they do not get from soil. Hence must be called heterotroph.
But they can form their own food by performing photosynthesis.
That is why they are known as partial heterotrophs.