Jason E. Andersen

Bonus Fun Fact: Mayflies have two penises. Well, technically they aren’t penises — that was a purposeful deception in the name of humor. They are actually penis-like appendages called aedeagi (or aedeagus in the singular). An aedeagus is the arthropod equivalent of the mammal penis, which is to say it’s the male reproductive organ through which sperm is secreted. Definitions aside, mayflies have two of them.

A devoted reader requested I do a fun fact on mayflies, given the season. Wanting to deliver, I did some research. Mayflies are very interesting creatures. They live as immature nymphs in fresh water bodies for most of their lives. They are most known for their sudden transformation into adulthood, where an entire local population will emerge at the same time, sending clouds of mayflies into the air that can number in the hundreds of thousands.

Bonus Bonus Fun Fact: Although mayflies are named after the month of May, their emergences may occur beginning early April through June, depending on local conditions and weather.

The adults only live for a brief period, usually not more than 24 hours, just long enough to reproduce and lay eggs, starting the process over again. Also, they have two sets of genitalia. When I read that, I knew it had to be my fun fact. That’s the kind of science I truly appreciate.

Bonus Bonus Bonus Fun Fact: The males are not alone in their dual-wielding of sexual weaponry — female mayflies also have two corresponding genitalia called gonopores. 

Bonus Bonus Bonus Bonus Fun Fact: There are reportedly 109 species of mayflies in Iowa and almost 630 species across North America.