Several problems. "Insecte" is plural, therefore it cannot be either "el" or "este". Also, this sentence is about sole existence ("there are"), not about what something is (e.g. "it is") - so you shouldn't present an extra pronoun at all.
I got this wrong and when the correct version came up at the bottom it said Există, not sunt. I think that is a new word and it is rather confusing to have two versions of the same sentence given as the correct one.