Observations by cksanders

EXPLORATION OF THE EPEORUS FROM THE HEPTAGENIIDAE FAMILY
By Curtis
The taxonomy of the Epeorus mayfly is starts with the Animalia kingdom, then to the phylum Arthropoda, subphylum Hexapoda, class Insecta, order Ephemeroptera, family Heptageniidae, and genus Epeorus. When identifying Epeorus morphological triats you can start with the gills. When identifying most aquatic insects the gills can be a large distinguishing factor to separate multiple genera. With Epeorus the first tracheal gills should be heart shaped or kidney shaped. Next you would look at the structure of the insect. The body of Epeorus is flattened since it is a clinger mayfly and live in stronger faster currents than the crawlers, swimmers, or diggers. Epeorus also has only two tails. This is the only mayfly that has two tails, all others will have three tails.
When distinguishing Epeorus for stoneflies, an aquatic insect that shares habitat and has two tails throughout the order, you will need to go to body structure where Epeorus won’t have the long antenna, long in proportion to body, that stoneflies have and the stoneflies won’t have the flattened body that clinger mayflies share. The color of Epeorus ranges from a dark brown to a black, but color isn’t a great factor to pick Epeorus out from other insects do to the fact that their color may not be the same that books state it is and brown is a common color among aquatic insects since it provides camouflage among rocks. With the color of Epeorus in my collection I found that some were lighter than what the book said they were to be. Being more lighter brown, not tan, with hints of olive rather than being a dark brown, but I did also collect some that were black. The size of the mayflies is 8 to 15 millimeters. The ones I collected fell into a 10 to 15 millimeter range being generally larger than the size shared in the books and articles. The habitat I found my collection in was similar in both locations. The habitat was fast current with a cobble bed found in smaller mountain rivers. The nymphs were found on the underside of the cobble.
When the Epeorus nymph goes through emergence they crawl to the bottom of the rock, where the current is weakest, they live on. Here the crawl out of their nymphal shuck and are then carried to the surface by buoyance. Epeorus adults then lay their eggs in riffles and the spinners then fall back to where they laid their eggs and are carried downstream where they are caught in backeddies where trout feed on them. Other nymphs in the family Heptageniidae don’t crawl under a rock. They’ll usually go near to shore or side channels where the current is weaker and trout are less present.

This was my findings of variation and location of the Epeorus nymph. This nymph holds its niche in the ecosystem by providing food for larger organisms and managing aquatic plant growth in mountain streams. The collection has showed how variation, isolation, and adaptation can change a species over time to fit its habitat and survive.

REFERENCES

Richmond, S. (n.d.). Yellow Quill. Retrieved May 19, 2016, from
http://www.west-fly-fishing.com/entomology/mayfly/yellow-quill.shtml