It depends on what you mean by communicate. Are you wanting to transmit data wirelessly between a Mayfly and another Arduino-compatible device? Or are you meaning a direct cable connection between the two devices? Either way is possible, but it really depends on a lot of factors, like what sort of data are you transferring, how often, and why.
As stated in the first post on this thread: This is the forum thread to ask general technical question about the Mayfly v1.1 board. If you’ve got a basic question such as what are the board’s features or how it differs from previous versions, this is the place to ask. If you’ve got a more complicated question or issue, then it is probably best to start your own thread. The goal of this thread is to be a great information resource for basic questions about the new v1.1 board that are common to all users.
So I’d suggest creating a new topic in the Mayfly forum for your question.