Most mayflies lay their eggs immediately after mating; the eggs then take anywhere from 10 days to many months to hatch. Cloeon cognatum is an exception. This species is ovoviviparous, which means that a mated female holds her eggs internally until embryonic development is complete (about 18 days), after which she lays them in water and they hatch immediately. This female was dropped onto the water surface moments before the video started. Video credit: David H. Funk
Does anybody reading along know if the time frame here is relative to all mayflies ???
This video led me to another from stroud research on DR. Ruth Patrick.
From what I've read this is a member of the baetis family?
Was this found in the US? I read that it is a UK bug. Please enlighten me.
Video was shot in Pennsylvania. And yes, most people now consider cognatum a synonym of dipterum, but no one has officially sunk it and our North American populations fit the old world cognatum concept. Cloeon dipterum in the broader sense is native to Eurasia and is undoubtedly a complex of species. It is not native to North America, but probably came over on ships in the mid 20th century. I have "barcoded" our local population (using the mitochondrial COI gene) and it matches exactly a specimen collected in Bulgaria. This species is now very common in northeast North America, especially in fishless ponds.