What is the symbiotic relationship between leaf hoppers and black ants?

Question

I have noticed several types of leaf hoppers on the Sunflowers in the garden. Black ants seem to be interacting with them but do not harm them.
The ants travel all over the plant, while the leaf hoppers are mainly on the underside.

Hemiptera is the order and I'm fully aware of what symbiotic means.

Answer 1

Some species of homoptera like leaf hoppers secrete a sugary liquid. The ants get it for food and offer protection from other insects that would eat the the leaf hoppers.