LH,

An additional question: Since Mayflies never reach a legal age to be able to vote, are they disenfranchised?

I presume this would apply to any animal that did not live at least 18 years (according to current law). This actually answers the amoeba question- if they are "new" individuals upon fission, then they are not old enough to vote. But if they are still the same ( single) individual, then it is certainly old enough: in fact, the oldest living thing, I suspect.