Stock Photo - Mayfly clings to marsh grass Yellow mayfly with grey eyes Mayflies live one to four years in the river bed or ponds and emerge to mate and die shortly after They have very short lifespan as adults ranging from one hour to about a day They are favorite food for fish and frogs Mouth is vestigal and digestive system is filled with air They do not eat as adults They are unique that they have paired sexual organs Males have double penis and female, double gonopores Front legs are developed, but not hind legs Mayflies with two long cerci at end of body are Epeorus, Compound eyes with three ocelli Significant insect in food chain Status unknown Srbsko, Czech Republic