Yellowstone Area Mayflies – More Than Meets the Eye

Mayflies are aquatic insects that only live in clean, well oxygenated, cold water. They are important indicators of high water quality. They are also pretty. My husband, Verne, has been taking pictures of some of the ones that live in Mill Creek north of Yellowstone in Paradise Valley for a fly fishing magazine article. Mayflies are an important part of a trout’s diet. They have four stages in their life cycle, two in the water, the egg and nymph stages, and two on land, the subadult or dun and the adult or spinner.
Most mayflies are fairly small. A nymph is usually about ½ inch long or shorter, as are the adult stages, not counting their tails, which can be fairly long.

A Mayfly Nymph
A Mayfly Nymph

Because mayflies are fairly small Verne uses microscope lens to take some of his photographs of them. He used a Zeiss Luminar lens on the mayfly nymph below. He took about 15 photos of it at slightly different focus points. He then “stacked” only the focused parts of each photo to create the photo you see below.

“Stacked” Green Drake Mayfly Nymph
“Stacked” Green Drake Mayfly Nymph

The following photo of a Flavilinea nymph is about 50 photos stacked together. It looks quite vicious don’t you think? I find it interesting that the nymph’s eyes are clean while the rest of its body is covered in algae. Can’t say that I have ever watched a nymph clean itself so I don’t know how they do that.

Stacked Flavilinea Nymph
Stacked Flavilinea Nymph

The green drake in the following photo is larger than many mayflies. It is only about 10 photos stacked together. It is a dun or subadult, a life cycle stage unique to mayflies. Subadults can fly but they can’t eat because they don’t have a digestive system or mouthparts. As a result they last less than 24 hours.

Stacked Green Drake Dun or Subadult
Stacked Green Drake Dun or Subadult

The adult or spinner below is about 25 photos stacked together. The spinner stage follows the dun stage. Spinners can’t eat either, in fact all they do is mate, the female lays eggs, and then they die, all within a few hours.

Stacked Mayfly Spinner or Adult
Stacked Mayfly Spinner or Adult

The closeup of a mayflies eye in the following photo is over 100 photos stacked together.

Our photos are available at www.vernelehmberg.com. Watch for an upcoming sale soon.

A Mayflies' Eyes
A Mayflies’ Eyes

3 thoughts on “Yellowstone Area Mayflies – More Than Meets the Eye

  1. They are vicious looking little things. I’m glad they don’t get very big. I am always learning something from you, Judy. Great photos and an interesting article. Thank you.

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