Is it possible to transfer mayflies from a lake to a pond for establishment? Anyone tried this and any idea if it would be worthwhile?

Have you considered why you don't already have an established Mayfly presence? What is the fish population ratio to pond size in carnivores and omnivores? Are other insect specie present such as Damselflies, Dragonflies, Midges etc.?

There have been posts on doing this on the forum in the past. Usually flying insects will colonize news BOW's if the correct conditions exist. Now if the lake you would be getting your mayflies from is so distant that they wouldn't reach your pond then transporting some adults mayflies to your pond may help them in seeding it.

It is better to transfer the immature bottom dwelling nymphs. Adults may not lay eggs. Adults only live one day in the final instar. The do not eat, their only mission as final instar adults is reproduction.

The lake that I go to is about 100 miles away. I may try to grab a few next time they hatch. I assume i would have to hope they lived for a 2 hour drive home. I guess I could try to scoop up some nymphs, but i'll have to research what they look like. And yes, there are dragonflies around here