The Stream Doctor

May 10th, 2004

Email YOUR Questions directly to the Stream Doctor. This is your opportunity to get an experts professional opinion on anything stream related.

Q. Thank you for your kind answer to my earlier question about Ephemerella "X". My question for this month is as follows: The other day I noticed some mayfly spinners in flight above a trout stream. They were flying straight up into the sky and then stopping and "gliding" down with their wings spread out. They would do this in a vertical column, up and down. They would rise to about 15 feet in the air and then drop to about 10 feet or so. It almost looked like they were playing, but insects don't "play". Is this some sort of mating ritual to attract the opposite sex? That is my guess. Thank you for your response, I look forward to reading it.

A. Thanks for the kind words. Your guess is right on the money; what you observed is the typical mating "dance" that many mayflies perform. The males are the ones doing the up-and-down "dancing." The females fly through the swarms and are seized from below by the males who then mate with them.

If you have a question, please feel free to contact me.
~ C. E. (Bert) Cushing, aka Streamdoctor
105 W. Cherokee Dr.
Estes Park, CO 80517
Phone: 970-577-1584

The 'Stream Doctor' is a retired professional stream ecologist and author, now living in the West and spending way too much time fly-fishing. You are invited to submit questions relating to anything stream related directly to him for use in this Q & A Feature at

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