The general appearance of this species is like a small grasshopper nymph. The body is dark brown dorsally, and lighter in color ventrally. The legs are yellow, darker at joints, and quite long, especially the hind legs, which are more than twice the length of the abdomen. The wings are very small and vestigial (micropterous), and seldom extend beyond the thorax. The wing venation is reduced to major veins, with few cross veins. The eyes are large and prominent, and the antennae are long, with around 35 segments. The maxillary palpi are long. The thorax is stout with oversized legs, and wings on the dorsolateral margins. The abdomen is as long as the head and thorax combined. Abdominal cerci are one-segmented.
Overview
Species Common Name Wahkeena Falls Flightless Stonefly
This species is a narrow Columbia Gorge endemic, only known from one watershed. Sites range in elevation from 380 to 470 m (1,250 to 1,540 ft.). Known habitat includes a large seepage area and a large spring head. Likely requires cold, spring-fed and seep habitat for nymphs and intact riparian systems for adults Nymphs are likely found in detritus and mosses at the edges of seeps and springs.
Limiting factors
Primary threats are habitat alteration and degradation, recreational use, and climate change. Its very limited range places this species at greater risk of extinction from various imminent and potential threats to its habitat. Predicted alterations to hydrologic regimes associated with climate change will also threaten this species.
Data gaps
Collect life history information. Obtain current population size and trend data. Research specific microhabitat requirements.
Conservation actions
Monitor populations and habitat. Protect habitat from disturbance.
Key reference or plan
Blackburn, M., S. Foltz Jordan, and E. Scheuering. 2020. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Nanonemoura wahkeena. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 26 pp. Read here
