Pteronarcys californica - Newport, 1848
Giant Salmonfly
Taxonomic Status: Accepted
Related ITIS Name(s): Pteronarcys californica Newport, 1848 (TSN 102473)
French Common Names: Ptéronarcys de Californie
Unique Identifier: ELEMENT_GLOBAL.2.112052
Element Code: IIPLE2V020
Informal Taxonomy: Animals, Invertebrates - Insects - Stoneflies
 
Kingdom Phylum Class Order Family Genus
Animalia Mandibulata Insecta Plecoptera Pteronarcyidae Pteronarcys
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Concept Reference
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Concept Reference: Stark, B.P. 1996. Last updated 16 February 2001. North American Stonefly List. Online. Available: http://www.mc.edu/campus/users/stark/Sfly0102.htm.
Concept Reference Code: N96STA01EHUS
Name Used in Concept Reference: Pteronarcys californica
Taxonomic Comments: An analysis of gene sequences from populations across North America revealed an eastern North American origin and 2 distinct genetic lineages with most of the current population structure in both lineages explained by a pattern of restricted gene flow with isolation by distance (presumably the result of dispersal via connected streams and rivers), but also some long-distance, overland dispersal (Kauwe et al., 2004).
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 31Aug2011
Global Status Last Changed: 18Jun1998
Rounded Global Status: G5 - Secure
Reasons: Range includes the Coast, Cascade, Rocky, and Sierra Nevada Mountains northward to Alaska and Yukon. The species has been well-studied because it is widely used by the commercial and recreational fly-fishing community at large. Populations have largely been considered secure but recent anecdotal evidence in Montana indicates a significant portion of the state's populations have declined over the last 70 years (particularly last 30 years) mostly through loss of habitat through siltation on increasing water temperatures beyond the species thermal limits. Similar declines have not yet been observed in other populations but studies have not been undertaken in this regard, either.
Nation: United States
National Status: N5 (01Jun2005)
Nation: Canada
National Status: N4N5 (27Apr2017)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alaska (SNR), Arizona (SNR), California (SNR), Colorado (SNR), Idaho (S5), Montana (SNR), Nevada (SNR), New Mexico (SNR), Oregon (SNR), Utah (S3?), Washington (SNR), Wyoming (SNR)
Canada Alberta (SU), British Columbia (S4S5), Yukon Territory (SU)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent: 20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Range Extent Comments: Range includes the Coast, Cascade, Rocky, and Sierra Nevada Mountains northward to Alaska and Yukon and southward to Mexico where it has been recorded disjunctly in Durango (Stewart and Oswood, 2006). It is found throughout the northern and eastern Basin and Range province of the western U.S. but is conspicuously absent in the western Great Basin, where P. princeps is the sole representative of the genus (Baumann et al., 1977; Kauwe et al., 2004; Sargent et al., 1991; Sheldon, 1979; Stark and Armitage, 2000; Stark et al., 1998; Stewart and Oswood, 2006; Stewart and Stark, 2002).

Number of Occurrences: > 300
Number of Occurrences Comments: Gaufin et al. (1972) cite Montana distribution as Beaverhead (Big Hole River), Flathead (Camas Creek, Kintla Creek, Swan River), Gallatin (Gallatin River, Madison River, West Gallatin River), Glacier (Elizabeth Creek), Granite (Flint Creek, Gilbert Creek, Rock Creek, Stony Creek), Lake (Swan River), Lewis and Clark (Prickley Pear Creek), Lincoln (Fisher River), Madison (Madison River, Spring Creek), Missoula (Blackfoot River, Lolo River, Rock Creek), Park (Yellowstone River), Ravalli (Bitterroot River, East Fork Bitterroot River, Cameron Creek, Camp Creek), and Sweet Grass (Boulder River) Cos. Baumann (1973) recorded it from Utah. Branham and Hathaway (1975) conducted a growth study on a population in the Provo River, Utah. Call and Baumann (2002) cite southern Utah distribution as Beaver Valley, Pine Valley Mountains, Sevier Plateau, Tushar Mountains, Wasatch Plateau, and Capitol Reef. Newell et al. (2006) report it from Glacier National Park in western Montana. Rockwell and Newell (2009) studied mortality in a population on the Jocko River, Montana. Gregory et al. (2000) documented emergence in streams in the Henry's Fork catchment, Idaho. In California, Jewett (1960) cited Butte, Kern, Marin, Mendocino, Placer, Plumas, San Mateo, Santa Clara, Sonoma, and Stanislaus Cos. Kauwe et al. (2004), in an analysis of global phylogeography, examined specimens from California (Lake, Mendocino, Shasta, Siskiyou Cos.), Idaho (Clark, Custer, Elmore, Fremont, Valley Cos.), Nelson and Hanson (1971) documented specimens from California, Colorado, Idaho, Montana, New Mexico, Oregon, Utah, Wyoming, and the Yukon. Montana (Madison, Park Cos.), Nevada (Elko Co.), New Mexico (San Miguel Co.), Oregon (Benton, Grant, Jackson Cos.), Utah (Beaver, Cache, Emory, Garfield, Utah, Weber Cos.), Washington (Walla Walla Co.), and Wyoming (Lincoln, Park, Pine Dale, Sheridan Cos.). Stewart and Ricker (1997) report the species from the Yukon for the first time from Klusha Creek on the Klondike Highway. Townsend and Pritchard (1998) documented it in the Crowsnest River in southern Alberta. Stewart and Oswood (2006) cite occurrences in British Columbia (Clearwater Lake, Okanagan River at Osoyoos Lake, Yellow Lake near Kaleden) and Yukon (Albert Creek, Little Rancheria Creek).

Population Size: >1,000,000 individuals
Population Size Comments: Locally, it can be very common in large to medium sized rivers at lower elevations (Stark et al., 1998); likely with millions of individuals worldwide.

Number of Occurrences with Good Viability/Integrity: Very many (>125)

Overall Threat Impact: Unknown
Overall Threat Impact Comments: Rockwell and Newell (2009) documented mortality due to cold air temperature following early emergence on the Jocko River in Montana. Also, throughout Montana, Stagliano (2010) concluded a significant portion of the state's populations to an estimated sum of ~350 river miles (~70 in the past 30 years) mostly through loss of habitat through siltation on increasing water temperatures beyond the species thermal limits. Otherwise, specific threat information has not been assessed.

Short-term Trend: Decline of <30% to relatively stable
Short-term Trend Comments: Throughout Montana, Stagliano (2010) concluded a significant portion of the state's populations have declined to an estimated sum of ~350 river miles (~70 in the past 30 years) mostly through loss of habitat through siltation on increasing water temperatures beyond the species thermal limits. Of particular concern are the Big Hole from Melrose to Browns Bridge and below Melrose, Madison River below Ennis Lake, Smith River above Camp Baker, and the Clark Fork River below the Milltown Dam site and below Missoula; and also sections of rivers (Big Hole, Rock Creek) that have experienced salmonfly decreases during the worst drought years but have rebounded in recent years.

Long-term Trend: Decline of <30% to increase of 25%

Intrinsic Vulnerability: Not intrinsically vulnerable
Intrinsic Vulnerability Comments: A recent analysis of gene sequences from populations across North America revealed an eastern North American origin and 2 distinct genetic lineages with most of the current population structure in both lineages explained by a pattern of restricted gene flow with isolation by distance (presumably the result of dispersal via connected streams and rivers), but also some long-distance, overland dispersal (Kauwe et al., 2004). The ability of the species to adapt and survive via long-distance dispersal makes it less vulnerable to random extirpation on a global level.

Environmental Specificity: Narrow. Specialist or community with key requirements common.
Environmental Specificity Comments: Rockwell and Newell (2009) documented mortality due to cold air temperature following early emergence on the Jocko River in Montana.

Other NatureServe Conservation Status Information

Distribution
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Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) Range includes the Coast, Cascade, Rocky, and Sierra Nevada Mountains northward to Alaska and Yukon and southward to Mexico where it has been recorded disjunctly in Durango (Stewart and Oswood, 2006). It is found throughout the northern and eastern Basin and Range province of the western U.S. but is conspicuously absent in the western Great Basin, where P. princeps is the sole representative of the genus (Baumann et al., 1977; Kauwe et al., 2004; Sargent et al., 1991; Sheldon, 1979; Stark and Armitage, 2000; Stark et al., 1998; Stewart and Oswood, 2006; Stewart and Stark, 2002).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AK, AZ, CA, CO, ID, MT, NM, NV, OR, UT, WA, WY
Canada AB, BC, YT

Range Map
No map available.

Ecology & Life History
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General Description: A full description is provided in Needham and Claassen (1925):
Color dark brown, paler beneath. Head blackish, supra-antennal plate ends in a sharp erect tooth. Median line on disc of prothorax obscurely reddish, widened toward its ends. Legs dark brown. Wings with blackish veins. Tails brown in middle, paler toward both ends. Pronotum nearly as long as broad, its front and sides straight, its hind margin convex, its angles obtuse.
Males. Ninth ventral segment little produced backward and not entirely covering the 10th sternite and set off at each side of the pleura by an impressed fold. Tenth tergite deeply divided above into two erect bluntly rounded lobes. Supra-anal plate developed as a corneous, and complicated sperm conveyor. Its superior margin runs out to rearward and ends in a free bifid tip; before this tip is a laterally flattened ventrally directed branch, that bears the sperm cup on its proximal side, just before an apical dilatation; subanal plates broad.
Female. Eight ventral segment bears just before its apical margin two somewhat equilateral-triangular processes whose tips reach the middle of segment 9.

Nymph morphology can be found in Stewart and Stark (1993).

Anatomy and morphology of adults and nymphs are discussed in Nelson and Hanson (1971).

Diagnostic Characteristics: This is the very largest species of all mayflies, stoneflies, and caddisflies, up to 2.5 inches long. Range only overlaps with two other potentially confusing species; the American salmonfly, Pteronarcys dorsata, and the ebony salmonfly, Pteronarcys princeps. P. princeps is generally darker and typically found in small streams on the west coast primarily but also in isolated mountain ranges of Nevada, eastern Oregon, and southwestern British Columbia. The tenth sternum (= ventral plate; essentially the very last segment) is greatly narrowed ventrally (as opposed to broad like in most species or absent in P. dorsata and P. pictetii). P. dorsata resembles P. californica in coloration but the ninth abdominal sternum (= ventral plate) of males projects over the tenth and is notched on the posterior margin (making the tenth plate appear absent); plus it only gets as far west in the Rocky Mountains as the Mississippi-Missouri drainage basin. In adults, the tenth abdominal tergum (= dorsal plate on the last segment) is rounded with raised lobes (unlike P. dorsata which is not raised) projecting about as high as their width unlike P. princeps where the lobes are plate-like (not rounded) and project higher than the width. In females, the posteromesal processes of the subgenital plate (= projections extending from the tail) are produced backward (unlike P. dorsata where they are reduced) and are about as long as they are wide at their base (unlike P. princeps where they are longer).

In mature nymphs, the prothoracic (= corner) teeth are directed outward and are sharp and longer than their basal width (unlike P. dorsata and P. princeps whose corner teeth are blunt and short and no longer than their basal width).

Reproduction Comments: This species has a semivoltine (2-, 3-, or rarely 4-year) life cycle including a 9-11 month diapause (Branham and Hathaway, 1975; DeWalt and Stewart, 1995; Freilich, 1991; Gaufin et al., 1972; Stewart and Stark, 2002). After three years in the water, mature nymphs emerge along the shoreline but emergence is earlier with higher water temperature (Gregory et al., 2000). Cold air temperature can kill emerging nymphs as was demonstrated on the Jocko River, Montana; where nymphs emerge earlier (early April through early May) than other streams in the United States (Rockwell and Newell, 2009). Emergence is timed with spring water temperature (Gregory et al., 2000). Small scale migration is heaviest near dawn and dusk. Adults are present in Alaska and western Canada mostly in May and June (Stewart and Oswood, 2006). Emergence time in the contiguous states is generally April to June (Stark et al., 1998), mid- to late May to as late as mid-June in eastern Idaho depending on water temperature (Gregory et al., 2000), early April through early May in northwestern Montana (Rockwell and Newell, 2009), and throughout May in southern Alberta (Townsend and Pritchard, 1998). It is on the wing in western mountains during June, July, and August (Needham and Claassen, 1925). Townsend and Pritchard (2000) studied aspects of egg development.
Ecology Comments: Movement patterns and gut content analysis were analyzed by Freilich (2006), who found the species has a three-year life cycle, females are larger than males at all ages, most movements are short as stoneflies stayed within a few meters of their first capture point, significant patch size is a stream reach 24 m long, and guts contained 75% diatoms, 15% vascular plant material, and 8% animal remains with females eating more than males.
Habitat Type: Freshwater
Non-Migrant: Y
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Nymphs were found to move a few (perhaps tens) meters each day with the fastest tagged individual moving 40 m in four days (or 22 m upstream in a single day) (Freilich, 1991). Small scale migration is heaviest near dawn and dusk.
Riverine Habitat(s): CREEK, High gradient, MEDIUM RIVER, Riffle
Special Habitat Factors: Benthic
Habitat Comments: Adults and larvae are associated with fast-moving mountain streams or large to medium sized rivers (2nd to 7th order streams) at relatively low to moderate elevations (Schwiebert, 2007; Stark et al., 1998; Merritt and Cummins, 1996). Streams are often clean and of moderate to high velocity and nymphs are frequently found in medium to large-sized, unconsolidated rocky substrates (Elder and Gaufin, 1973; Kauwe et al., 2004). Freilich (1991) found nymphs most abundant in areas of fast, deep water with large, loosely embedded cobbles, and never in pools or on areas with silty bottoms in the Grand Teton National Park.
Immature Food Habits: Detritivore
Food Comments: Nymphs are considered major shredders of CPOM (coarse particulate organic matter) in stream systems (Cummins et al., 1973; Short and Maslen, 1977) but are poorly adapted to digest detrital polysaccharides (Martin et al., 1981). Gut content was found to be 75% diatoms, 15% vascular plant material, and 8% animal remains (Freilich, 1991). Richardson and Gaufin (1971) conducted feeding studies.
Adult Phenology: Circadian
Immature Phenology: Nocturnal
Phenology Comments: It is on the wing during June, July and August with the easternmost specimen the earliest in season (April 25) (Needham and Claassen, 1925). Although adults, when they hatch, are active during daylight, Elder and Gaufin (1973) indicated this species has nocturnal habits as nymphs and this was supported by Freilich (1991). Elder and Gaufin (1973) stated the aquatic stage lasts three years in the Provo River, Utah, although the basis for this statement is unclear. Branham and Hathaway (1975) used larval body mass and estimated a four-year larval life cycle in the same river. Freilich (1991) reported a three-year larval life cycle in Pacific Creek, Wyoming. DeWalt and Stewart (1995) found a 9- to 10-month egg stage and estimated a 38-month larval life cycle in the Rio Conejos, Colorado. Townsend and Pritchard (1998) concluded embryonic development, incorporating an early diapause, accounts for approximately one year of the life cycle followed by a further four years in the larval stage in Alberta. Examination of genetic differentiation among cohorts from Utah suggests four and five year life cycles comprising an approximate one year embryonic diapause followed by either three or four years of larval development (Schultheis et al., 2008).
Length: 3.2 centimeters
Economic Attributes
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Economic Comments: The giant salmonfly is an important food source for trout. As such, both the larvae and adults are used extensively both live and as models by fly fishermen to create natural and artificial lures (Schwiebert, 2007).
Management Summary Not yet assessed
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Population/Occurrence Delineation
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Group Name: Stoneflies

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical presence or current presence of single or multiple specimens (including nymphs or adults) at a given location with potentially recurring existence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information. A photograph may be accepted as documentation of an element occurrence for adults only (nymphs and subimagos are too difficult to identify in this manner) provided that the photograph shows diagnostic features that clearly delineate the species from other species with similar features. Sight records, though valuable, should not be accepted as the basis for element occurrences. Instead, such records should be utilized to further study an area to verify the element occurrence in that area.
Separation Barriers: Within catchments there are likely no significant barriers to movement of adults between microhabitats, with even extensive sections of inappropriate waterway or major obstructions to flow being readily traversed by adults during dispersal following emergence.
Separation Distance for Unsuitable Habitat: 3 km
Separation Distance for Suitable Habitat: 3 km
Alternate Separation Procedure: None
Separation Justification: Stoneflies (Order Plecoptera) are a relatively small insect order with an immature larval stage that is entirely aquatic in North America. Nymphs of most genera occur in cold lotic habitats, with several occurring in warm lotic systems, comparatively few in cold lentic habitats, and none in warm lentic habitats (Baumann, 1979). Dispersal is primarily accomplished stochastically by nymphs and actively by winged adults; although the adult of Capnia lacustra Jewett, 1965, is entirely aquatic (Jewett, 1962) and Capnura fibula (Claassen, 1924), and Allocapnia vivipara (Claassen, 1924) are apparently wingless (Jewett, 1960). Numbers of described North American species (in nine families) have steadily grown from 350 (Jewett, 1960) to 537 (Stark et al., 1986) to 550 (Stewart and Stark, 1993) to 575 (DeWalt and Stewart, 1995) and most recently 614 (Stark et al., 1998).

Separation distances (unsuitable and suitable) have been set at three km based upon several life history characteristics that limit occurrences to the area of emergence, among them: (1) most stoneflies require some form of moving water for development of nymphs (Hynes in Stark and Armitage, 2000; Jewett, 1960); (2) although some species occur in cool lentic habitats, no stonefly genera occur in warm lentic habitats and most cool lentic taxa live along active, wave-swept areas of shorelines (Hynes in Stark and Armitage, 2000; Stark et al., 1996); (3) although drift does occur for some species, drft tendency is low for stoneflies (Stewart and Szczytko, 1983); (4) stonefly adults generally remain in the area (within m) of larval emergence and mate on nearby solid substratum (Brittain, 1990; Bubb et al., 2004; Cummins and Merritt, 1996); (5) the known life cycle of North American stoneflies is either univoltine (one year) or semivoltine (two or three years) (Hynes in Stark and Armitage, 2000; Stewart and Ricker, 1997; Stewart and Stark, 1993); (6) flying ability (particularly for adult females) is not strong with dispersal rarely exceeding a few km (Malmqvist, 2000) wherein, according to Stewart and Stark (1993), "most students of plecopteran biogeography have emphasized low vagility of adult stoneflies and the necessity for former land bridges or vicariant events to account for range disjunctions"; (7) recently, limited wind-driven dispersal of adults between tributaries has been demonstrated wherein Bubb et al. (2004) showed that between 0.1% and 0.2% of a population of Leuctra inermis moved a distance of 1 km while a very small percentage of a population of Peltoperla tarteri demonstrated genetic flow over 0.5 to 2.0 km (Schultheis et al., 2002).

Date: 18Oct2004
Author: Cordeiro, J.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 31Aug2011
NatureServe Conservation Status Factors Author: Cordeiro, J.
Element Ecology & Life History Edition Date: 31Aug2011
Element Ecology & Life History Author(s): Cordeiro, J.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
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  • Baumann, R.W. 1973. Studies on Utah stoneflies (Plecoptera). Great Basin Naturalist 33:91-108.

  • Branham, J.M. and R.R. Hathaway. 1975. Sexual differences in the growth of Pteronarcys californica Newport and Pteronarcella badia (Hagen) (Plecoptera). Canadian Journal of Zoology 53(5):501-506.

  • Call, R.G. and R.W. Baumann. 2002. Stoneflies (Plecoptera) of southern Utah with an updated checklist of Utah species. Monographs of the Western North American Naturalist 1:65-89.

  • Clifford, H.F. 1991. Aquatic Invertebrates of Alberta. University of Alberta Press: Edmonton, Alberta. 538 pp.

  • Cummins, K.W., R.C. Petersen, F.O. Howard, J.C. Wuycheck, and V.I. Holt. 1973. The utilization of leaf litter by stream detritivores. Ecology 54:336-345.

  • DeWalt, R.E. and K.W. Stewart. 1995. Life histories of stoneflies (Plecoptera) in the Rio Conejos of southern Colorado. The Great Basin Naturalist 55(1):1-18.

  • Elder, J.A. and A.R. Gaufin. 1973. Notes on the occurrence and distribution of Pteronarcys californica Newport (Plecoptera) within streams. Great Basin Naturalist 33:218-220.

  • Freilich, J.E. 1991. Movement patterns and ecology of Pteronarcys nymphs (Plecoptera): Observations of marked individuals in a Rocky Mountain stream. Freshwater Biology 25:379-394.

  • Freilich, J.E. 2006. Movement patterns and ecology of Pteronarcys nymphs (Plecoptera): Observations of marked individuals in a Rocky Mountain stream. Freshwater Biology 25(2):379-394.

  • Gaufin, A.R., E.R. Ricker, M. Miner, P. Milam, and R.A. Hays. 1972. The stoneflies (Plecoptera) of Montana. Transactions of the American Entomological Society 98(1):1-161.

  • Gregory, J.S., S.S. Beesley, and R.W. Van Kirk. 2000. Effect of springtime water temperature on the time of emergence and size of Pteronarcys californica in the Henry's Fork catchment, Idaho, U.S.A. Freshwater Biology 45:75-83.

  • Jacobi, G.Z., S.J. Cary, and R.W. Baumann. 2005. An updated list of the stoneflies (Plecoptera) of New Mexico, U.S.A. Entomological News 116(1): 29-34

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  • Kruse, Jim. 2003. University of Alaska Museum Insect Omnibus: a Preliminary checklist of the Insects of Alaska. Order Plecoptera, Stoneflies. Available: http:/www.uaf.edu/museum/Insect_Omnibus/Plecoptera/index. Updated 7 April 2003. Accessed: 16 April 2003

  • Merritt, R. W. and K. W. Cummins. 1996. An Introduction to the Aquatic Insects of North America. Third Edition. Kendall/ Hunt Publishing Company: Dubuque, Iowa. 862 pp.

  • Nebeker, A.V. and A.R. Gaufin. 1966. New stoneflies from Idaho (Plecoptera). Entomological News 77: 36-43.

  • Needham, J.G. and P.W. Claassen. 1925 [reprinted 1970]. A Monograph of the Plecoptera or Stoneflies of America North of Mexico. Thomas Say Foundation of the Entomological Society of America, Volume 2: Lafayette, Indiana. 397 pp.

  • Nelson, C.H. and J.F. Hanson. 1971. Contribution to the anatomy and phylogeny of the family Pteronarcidae (Plecoptera). Transactions of the American Entomological Society 97(1):123-200.

  • Newell, R.L., R.W. Baumann, and J.A. Stanford. 2006. Pages 173-186 in F.R. Hauer, J.A. Stanford, and R.L. Newell. 2006. International Advances in the Ecology, Zoogeography, and Systematics of Mayflies and Stoneflies. University of California Press, Ecology series, Volume 128. 311 pp.

  • Richardson, J.W. and A.R. Gaufin. 1971. Food habits of some western stonefly nymphs. Transactions of the American Entomological Society 97:91-121.

  • Rockwell, I.P. and R.L. Newell. 2009. Note on mortality of the emerging stonefly Pteronarcys californica on the Jocko River, Montana, USA. Western North American Naturalist 69(2):264-266.

  • Sargent, B.J., R.W. Baumann, and B.C. Kondratieff. 1991. Zoogeographic affinities of the Nearctic stonefly (Plecoptera) fauna of Mexico. The Southwestern Naturalist 36(3):323-331.

  • Schultheis, A.S., J.Y. Booth, M.R. Vinson, and M.P. Miller. 2008. Genetic evidence for cohort splitting in the merovoltine stonefly Pteronarcys californica (Newport) in Blacksmith Fork, Utah. Aquatic Insects 30(3):187-195.

  • Schwiebert, E.G. 2007. Nymphs. Volume II. Stoneflies, Caddisflies, and Other Important Insects Including the Lesser Mayflies. Lyons Press: Guilford, Connecticut. 787 pp.

  • Sheldon, A.L. 1979. Stonefly (Plecoptera) records from the basin and ranges of Nevada and Utah. Great Basin Naturalist 39:289-292.

  • Short, R.A. and P.E. Maslin. 1977. Processing of leaf litter by a stream detritivore: Effect on nutrient availability to collectors. Ecology 58:935-938.

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  • Stark, B.P. 1996. Last updated 16 February 2001. North American Stonefly List. Online. Available: http://www.mc.edu/campus/users/stark/Sfly0102.htm.

  • Stark, B.P. and B.J. Armitage (eds.). 2000. Stoneflies (Plecoptera) of eastern North America. Volume 1. Pteronarcyidae, Peltoperlidae, and Taeniopterygidae. Bulletin of the Ohio Biological Survey New Series 14(1):1-99.

  • Stark, B.P., S.W. Szczytko, C.R. Nelson. 1998. American Stoneflies: A Photographic Guide to the Plecoptera. Caddis Press, Columbus, Ohio. 126 pp.

  • Stewart, K.W. and B.P. Stark. 1993. Nymphs of North American Stonefly Genera (Plecoptera). Second Edition. University of North Texas Press, Denton, Texas. 460 pp.

  • Stewart, K.W. and B.P. Stark. 2002. Nymphs of North American Stonefly Genera (Plecoptera). 2nd edition. The Caddis Press: Columbus, Ohio. 510 pp.

  • Stewart, K.W. and M.W. Oswood. 2006. The Stoneflies (Plecoptera) of Alaska and Western Canada. The Caddis Press: Columbus, Ohio. 325 pp.

  • Stewart, K.W. and W.E. Ricker. 1997. Stoneflies (Plecoptera) of the Yukon. Pages 201-222 in H.V. Danks and J.A. Downes (eds.), Insects of the Yukon. Biological Survey of Canada (Terrestrial Arthropods): Ottawa. 1034 pp.

  • Sutton, M.Q. 1985. The California salmon fly as a food source in northeastern California. Journal of California Great Basin Anthropology 7:176-182.

  • Townsend, G.D. and G. Pritchard. 1998. Larval growth and development of the stonefly Pteronarcys californica (Insecta: Plecoptera) in the Crownest River, Alberta. Canadian Journal of Zoology 76(12):2274-2280.

  • Townsend, G.D. and G. Pritchard. 2000. Egg development in the stonefly Pteronarcys californica Newport (Plecoptera: Pteronarcyidae). Aquatic Insects: International Journal of Freshwater Entomology 22:19-26.

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Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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