“Once a year, billions of mayflies converge on a lake in Russia’s Primorye province to mate, spawn and die… all on a single day.” The video remarks that a year ago, ‘thousands’ of mayflies laid their eggs over the Primorye lake. That translated into billions of mayflies? So later, how many of those billions were females that laid eggs? I find all these math problems so confusing…kind of like the two trains departing, math problem….always terrible at algebra. 

WILD RUSSIA Episode 7 Mayfly Hatch 

A different Russian Dance of the Mayflies by Sergei Dolmatov...blame it on my Post Op pain meds.