Field Notes – April, 2025

Rare Stoneflies of the Southern Appalachians

The macroinvertebrate fauna of the Southern Appalachians may be one of the most diverse in the world. Taxonomic textbooks note that there are over 300 species of mayflies and stoneflies in our streams and rivers and an incredible number of caddisflies, well over 600 species. And those are only the organisms that we know about.

Scientists are finding new species and looking for them in understudied habitats, like very small mountain streams. In a recent paper by Chris Verdone and Boris Kondratieff¹ the authors discuss the ecology of three rare stoneflies that are possibly found in the upper Laurel River watershed. These three listed species are considered highly endemic and their ecology poorly understood. The identification of these three species is very difficult and can only be confirmed by examining adult specimens, which are only present for a week or two. However, finding the larvae of these species could be evidence of their presence.

Acroneuria kosztarabi (Virginia Stone)

Acroneuria are large, free-roaming predators in the family Perlidae. Morse et al.² lists 11 species commonly found in the southeastern US; A. kosztarabi isn't among them because of its rarity. The majority of A. kosztarabi specimens collected were from Wolf Creek, Virginia, a 4th order stream with a drainage area of 42.8 km² and a mixed substrata of gravel and cobbles. Elevation at this location is 725 meters.

The authors note that they found A. kosztarabi from 22 locations and mention that "judging from existing records it is likely that this species also occurs in northern North Carolina and eastern West Virginia." The preferred habitat of A. kosztarabi seems to be pools and deep runs, rather than riffles where we would commonly collect Acroneuria abnormis (very common).

Remenus kirchneri (Blueridge Springfly)

The genus is also a common predator in streams and easily identified having only one lacinial tooth, unlike all other Perlodidae. The Morse key lists only two species found in the southeast and does not include R. kirchneri. This species is most often collected in very small first-order streams along the Blue Ridge Parkway, including one in North Carolina (Garden Creek).

The authors note that the typical stream where this species occurs has minimal flow, often only a few centimeters deep, and the substrate consists of pea-sized gravel, silt, small cobbles, woody snags, and leaf packs. Interestingly these larvae are frequently found in leaf packs, presumably searching for prey, or on the undersides of large rocks. Many of our ATBI sites appear to fit the preferred habitat of R. kirchneri.

Tallaperla lobata (Lobed Roachfly)

Tallaperla are very common in leaf packs where they feed on microorganisms and effectively shred leaf material. Morse does not speciate Tallaperla in the Clemson key but notes that Viehoperla ada and Peltoperla spp. are also found in very small, high-elevation streams.

Typical streams that this species inhabits have substrata consisting of pea-sized gravel, silt, small cobbles, bedrock, woody snags, and leaf packs. It is very likely that Tallaperla lobata can be found in our ATBI locations.

References

1)Taxonomy, Life Histories, Populations Statuses, Abundance, Distribution and Summary of Potential Threats to Three Species of Eastern Nearctic Stoneflies (Plecoptera), The Lobed Roachfly (Tallaperla lobata, Stark, 1983), Blueridge Springfly (Remenus kirchneri, Kondratieff & Nelson, 1995) and Virginia Stone (Acroneuria kosztarabi, Kondratieff & Kirchner, 1993)

2) Morse, J. C., W.P. McCafferty, B.P. Stark, & L.M. Jacobus, editors. 2017. Larvae of the Southeastern USA Mayfly, Stonefly and Caddisfly Species. Biota of South Carolina. Vol 9, Clemson University Public Service Publishing, Clemson University, Clemson, South Carolina, USA 482 pp.