Finding a port's dependency which requires universal?

[MK-MacPorts at techno.ms]

I wanted to try out wxmaxima and realize now that dozens of ports get rebuild in their universal variant...

How can I locate which of wxmaxima's deps requires the universal variant in the first place?

Perhaps there is a way to avoid this whole rebuilding…

Why do I need universal after all in this case? Can it be that some functionality cannot be implemented with 64 bits and therefore needs the i386 architecture?