Happy Macroinvertebrate Monday from the American Salmonfly/Giant Black Stonefly (Pteronarcys dorsata)! These are the largest species of stonefly in the eastern and midwestern United States. They reside in moderate- to high-gradient streams. These streams are primarily cold-water, some often cool-water, with high levels of dissolved oxygen. During months with warmer water temps, P. dorsata nymphs have been found living in mats of aquatic vegetation when present.
Dorsal view highlighting the large, armor-like plates on their pronotum and thorax
P. dorsata are a popular species to imitate with nymphs by the fly fishing community as they offer a large presentation to the resident fishes. They are also a great indicator species of water quality by having low tolerance to chemistry changes and temperature/dissolved oxygen limitations. These nymphs feed on decaying plant matter and algae in the water column. Emerging adults have only one goal in mind and that is to reproduce. They do not eat and live for less than a month
Ventral view of P. dorsata showing the large gill tufts they use to breath underwater
Fun fact, the nymphs of the American Salmonfly can take 2-4 years to fully develop before emerging from their aquatic lives!
Comments