Question

Angraecoid orchids provide nectar to the African moths. The moths in turn help in pollinating the plant . What type of evolution do these two species follow

Answer 1

I believe you mean species interaction? If you do mean evolution, please elaborate and I would be happy to help you with that, too. 

The species interaction is mutualism. Mutualism is a symbiotic interaction where both individuals benefit from the relationship - in this case, the orchids provide nectar to the moths which benefit the moths, and the moths pollinate the plant, which benefits the plant.