That is an interesting question. I never think they need a pollinator and wonder how they pollinate, but I do know that they have both male and female flowers in the same bloom. Most of them bloom and fruit by their own. That must have meant that they are self pollinator. So that means you don't need a cross pollinator plant. However, the question remains, can bananas cross polinate among species? I'm sure they do because I do have a banana that is a cross between Zebrina and Gran Nain to produce Sumatrana X. How they do it, I have no idea. Back to your question, you can be sure that your banana will produce fruit without another partner. However, some varieties of bananas do not produce edible fruit. Orinoco will give you edible fruit.

I am almost sure they are self fertile, but to encourage fruiting, use fertilizers that are potassium rich

Here is a link that might be useful: Jeremy- Moths and Butterflies