Perlid Stoneflies Research Articles

Using distribution models to identify range shifts of four Acroneuria Pictet, 1841 (Plecoptera: Perlidae) species in the Midwest USA

Regional faunal assessments of stoneflies in the United States Midwest (herein defined as Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio, and Wisconsin) indicate increasing imperilment resulting from human disturbance and climate change. Large-bodied perlid stoneflies with multivoltine life cycles are among the most at risk for regional extirpation, with losses reported in several midwestern states. Species distribution modeling was undertaken to describe distribution shifts for four widespread riverine species: Acroneuria abnormis (Newman, 1838), A. frisoni Stark & Brown, 1991, A. internata (Walker, 1852) and A. lycorias (Newman, 1839). The distribution modeling algorithm MaxEnt was selected to predict both the historical (i.e., pre-1960) and contemporaneous distributions for each species using separate occurrence datasets. These models permit the identification of suitable habitat loss through range contractions associated with human disturbance. Predictions of suitable habitat losses were recorded for multiple species but were greatest for A. abnormis and A. internata. These models serve to guide future collection efforts and to further describe patterns of regional biodiversity loss.

Two new species of Kamimuria (Plecoptera, Perlidae) from China

Kamimuria hunanensis sp. n. and Kamimuria ziwulinga sp. n., two new perlid stoneflies from Hunan and Shaanxi provinces, respectively, are described as new to science. Their morphological characters are described and compared to related congeners. The distributions of all Kamimuria species known from China are summarized.

Temperature dependence of metabolic rate in tropical and temperate aquatic insects: Support for the Climate Variability Hypothesis in mayflies but not stoneflies.

A fundamental gap in climate change vulnerability research is an understanding of the relative thermal sensitivity of ectotherms. Aquatic insects are vital to stream ecosystem function and biodiversity but insufficiently studied with respect to their thermal physiology. With global temperatures rising at an unprecedented rate, it is imperative that we know how aquatic insects respond to increasing temperature and whether these responses vary among taxa, latitudes, and elevations. We evaluated the thermal sensitivity of standard metabolic rate in stream-dwelling baetid mayflies and perlid stoneflies across a ~2,000m elevation gradient in the temperate Rocky Mountains in Colorado, USA, and the tropical Andes in Napo, Ecuador. We used temperature-controlled water baths and microrespirometry to estimate changes in oxygen consumption. Tropical mayflies generally exhibited greater thermal sensitivity in metabolism compared to temperate mayflies; tropical mayfly metabolic rates increased more rapidly with temperature and the insects more frequently exhibited behavioral signs of thermal stress. By contrast, temperate and tropical stoneflies did not clearly differ. Varied responses to temperature among baetid mayflies and perlid stoneflies may reflect differences in evolutionary history or ecological roles as herbivores and predators, respectively. Our results show that there is physiological variation across elevations and species and that low-elevation tropical mayflies may be especially imperiled by climate warming. Given such variation among species, broad generalizations about the vulnerability of tropical ectotherms should be made more cautiously.

New and little known species of Kamimuria (Plecoptera: Perlidae) from Fujian of China.

Kamimuria shiae sp. n. and K. tenuilobata sp. n., two new perlid stoneflies from Wuyi Mountains of Fujian Province, eastern China, are described as new to science. The new species are compared with similar congeners. Kamimuria robusta Wu, 1948 is rediscovered from the type locality of the same mountain.

The complete mitochondrial genome of a stonefly species, Neoperlops gressitti (Plecoptera: Pelidae)

The small genus Neoperlops only contains four species over the whole world now, and the mitochondrial genome of the genus Neoperlops is still a gap. Here, we report the complete mitochondrial genome of Neoperlops gressitti representing the rare perlid stonefly genus Neoperlops. The circular mitochondrial genome is 15,699 bp in length, which consisting of A (33.30%), G (12.5%), T (29.7%), and C (24.6%), and it is composed of 22 tRNA genes, 13 protein-coding genes (PCGs), two rRNA genes, and a control region like the other published stonefly. In all PCGs, eleven genes initial with the typical start codon ATN, the rest of the two genes (ND1, ND2) with TTG. All PCGs stop with TAG/TAA, except COIII, ND5 use incomplete T—as stop codon. Besides, the phylogenetic result based on the nucleotide of the 13 PCGs and two rRNA genes by using Bayesian (BI) method supports the sister relationship between N. gressitti and Dinocras cephalotes. The complete mitogenome of N. gressitti can provide genetics data to further explore the taxonomic status of Pelidae.

Anacroneuria flintorum Froehlich 2002 (Plecoptera: Perlidae): Notes, distribution, and life stages association using molecular tools.

Specimens of the perlid stonefly Anacroneuria flintorum from different regions of the Brazilian Atlantic Forest along the Atlantic coast of Brazil were studied. In this paper, the nymph of A. flintorum is described based on reared specimens and molecular associations. Additionally, we provide new locality records and comments about variation of the species.

The complete mitochondrial genome of the stonefly Dinocras cephalotes (Plecoptera, Perlidae)

The complete mitochondrial genome of the perlid stonefly Dinocras cephalotes (Curtis, 1827) was sequenced using a combined 454 and Sanger sequencing approach using the known sequence of Pteronarcys princeps Banks, 1907 (Pteronarcyidae), to identify homologous 454 reads. The genome is 15,666 bp in length and includes 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a control region. Gene order resembles that of basal arthropods. The base composition of the genome is A (33.5%), T (29.0%), C (24.4%) and G (13.1%). This is the second published mitogenome for the order Plecoptera and will be useful in future phylogenetic analysis.

Assessing the functional importance of large‐bodied invertebrates in experimental headwater streams

Recent theoretical advances in food web ecology emphasize the importance of body size disparities among species for the structure, stability and functions of ecosystems. Experimental confirmations of the functional importance of large species, independent of their trophic position, are scarce. We specifically examine the multiple ecological roles of large invertebrates from two distinct trophic levels in headwater streams. We experimentally manipulated the presence of large predatory invertebrates (two Perlid stoneflies) or detritivores (a limnephilid caddisfly and aPteronarcysstonefly) in a two‐by‐two design in stream channels open to immigration/emigration of smaller biota. We assessed treatment effects on the trophic structure of the benthic invertebrate community, dynamics of basal resources (benthic algae and leaf litter of cedar and alder), and stability of litter decomposition rates against an experimental pulse perturbation (fine sediment input). The presence of the large invertebrates was associated with a ten‐fold decrease in the biomass of invertebrate filterers whereas other trophic groups were unaffected by the large species. The biomass of benthic algae was lower and the rate of mass loss of alder litter was higher in channels lacking the large predators, thus revealing trophic cascades operating along both algal‐based and detritus‐based food chains. The large predators had no detectable effect on the decomposition of cedar whereas both cedar and alder disappeared faster in the presence of the large detritivores. Furthermore, the large predators and large detritivores interactively influenced the decomposition of the cedar–alder mixture through a litter diversity effect and the variability of the rate of alder decomposition after a pulse of fine sediment. Because the large invertebrates affected multiple ecosystem properties, and as their absence was not rapidly compensated for by small immigrant species, our findings support the notion that large species could be critically important in controlling ecosystem structure and functioning.

New Species of Acroneuria (Plecoptera: Perlidae: Acroneuriinae) from Tropical Southeast Asia

Abstract Two new species of perlid stoneflies, Acroneuria bachma n. sp. and A. magnifica n. sp., are described from tropical Vietnam. Descriptions of these species are given based on male and female adults, nymphs, and eggs. The adult of A. bachma is distinguished by the presence of a large dark brown marking in the interocellar area and by the absence of patches of sensilla basiconica on the 9th abdominal tergum; the nymph is distinguished by the presence of a narrow and complete M-line marking on head and by the absence of gills on paraprocts. The adult of A. magnifica is distinguished by presence of a distinct light-yellow M-line marking on head and patches of sensilla basiconica which are sparsely distributed on the 9th abdominal tergum; the nymph is distinguished by the presence of an incomplete M-line marking on head and gills on paraprocts. Line-drawings and macro-photographs of the diagnostic characters are provided. Adult and nymphal keys to Southeast Asian species of Acroneuria are also provided.

Response of a stream diatom community to top predator manipulations

I investigated the effects top predator manipulations have on the community structure of benthic diatoms in a small, third-ordered stream ecosystem. Following the concept of trophic cascades in food webs, changes in top predator abundance should, via herbivore elimination, influence community metrics and species composition of stream periphyton. Using in situ stream enclosures, I varied the density of two common stream predators, sculpin and a perlid stonefly larva. Over three weeks, in three seasons, I sampled both invertebrate prey and diatoms from tiles placed in each enclosure. Diatoms did respond to predator manipulations. Changes in diversity, species richness, evenness, and dominance varied with treatment and between seasons. Cluster analysis showed pronounced assemblage dissimilarities before and after predator manipulations. However, species composition did not change between treatments, though rankings of the ten most abundant species did shift. Top predators can alter the community composition and structure of stream benthic algae indirectly through grazer suppression and directly by disruption due to foraging activity. This study demonstrates that top predators can impact nonadjacent trophic levels and that predator type and abundance should be considered when comparing diatom communities temporally and spatially.

Multiple predator effects on microdistributions, survival, and drift of stream hydropsychid caddisflies

We studied microdistributions, survival, and drift of larval hydropsychid caddisflies in the physical and/or chemical presence of 2 types of benthic predators with different foraging modes. Sculpins (Cottus bairdi, C. cognatus) are ambush predators, whereas perlid stoneflies (Acroneuria, Paragnetina) are stalkers, and stoneflies are an intermediate predator consumed by sculpins. Hydropsychid larvae in a northern Michigan stream were significantly more abundant in crevices than on flat surfaces on real cobbles in riffles with both predators. Larval colonization on experimental substrates (bricks) in 7 riffles was greater in crevices (grooves) than on flat surfaces, and the greatest differences in larval densities between these microhabitats occurred where predator densities were highest. Mean size (head capsule width) of larvae in both microhabitats was negatively related to densities of sculpins, but not stoneflies. A multifactorial experiment done in artificial stream channels revealed that caddisflies selected crevices over flat surfaces even in predator-free conditions. Sculpin and stonefly effects on hydropsychid survival were additive, suggesting a lack of multiple predator effects. Crevices provided a refuge from predators; however, stoneflies were more effective than large sculpins (>65 mm total length) at consuming hydropsychids in crevices. Like caddisflies, stoneflies predominantly occupied crevices, but stonefly crevice use and activity were not affected by sculpins, and no stoneflies were consumed by sculpins. Caddisfly drift was ∼3 to 4× greater in the physical presence of each predator than in predator-free channels. However, drift by caddisflies in the physical presence of both predators was lower than expected (i.e., nonadditive), suggesting it is less risky to remain in retreats (i.e., immovable cases) than to drift when both predators are present. Elevated chemical cues of either predator did not trigger drift responses by these sedentary prey. Crevice use and drift appear to be key mechanisms enabling larval hydropsychid caddisflies to coexist with a multispecies complex of predators.

Impaired Acroneuria sp. (Plecoptera, Perlidae) populations associated with aluminum contamination in neutral pH surface waters.

Our aim was to quantify impairment to invertebrate predator populations, particularly to Acroneuria sp. (Plecoptera, Perlidae), downstream of an acid mine drainage-impacted tributary to the North Fork of the Powell River, southwestern Virginia. Predatory insects comprised 9.0 +/- 1.3% of the total abundance at the three stations upstream of the impacted tributary, but were significantly reduced (p = 0.0039) downstream (3.9 +/- 0.6%). Acroneuria sp. populations followed the same trend, with the upstream average (2.3 and 2.8%) being significantly higher (p < 0.05) than the downstream averages (0.2 and 0%) during 1999 and 2000, respectively. Using correlation analysis, we evaluated the relationship between the percent abundance of Acroneuria sp. throughout this reach and metal concentrations in water, sediment, and biological tissues (invertebrate predators and primary consumers). Water column aluminum (Al) concentration was the only parameter that was significantly correlated with percent Acroneuria sp. abundance, with correlation coefficients of -0.845 and -0.873 during 1999 and 2000, respectively. While this correlation exists, it may not indicate a causal relationship, and experiments should be conducted to determine the long-term toxicity of various Al species to perlid stoneflies.

Food web quantification using secondary production analysis: predaceous invertebrates of the snag habitat in a subtropical river

1. Secondary production was estimated for Plecoptera, Odonata and Megaloptera (mostly large predators) occurring on the snag habitat of a subtropical blackwater river in the southeastern U.S.A. Coastal Plain for 2 years. Production estimates and gut analyses were used in estimating species‐specific ingestion to construct a quantitative food web of the predator portion of the invertebrate assemblage. Neither basal resources (e.g. detritus) nor predaceous vertebrates (e.g. fishes) were considered in this analysis. A discharge‐specific model of snag‐habitat availability was used to convert values per m2 of snag surface to values per m2 of river bed. 2. These three orders included the major large predators on the snag habitat, as well as two detritivorous stoneflies. The major predators were the hellgrammite (Corydaluscornutus), five perlid stoneflies (Paragnetinakansensis, Perlestaplacida, Neoperlaclymene, Acroneuriaevoluta and Acroneuriaabnormis) and two dragonflies (Neurocorduliamolesta and Boyeriavinosa). The detritivores were Pteronarcysdorsata and Taeniopteryxlita. 3. Total predator production was high, but varied from only 7.1 to 7.4 g dry mass (DM) m−2 y−1 of snag surface (2.4–2.7 g DM m−2 y−1 of river bed) over two years. Corydalus was the largest predator and had the highest production (2.8–3.1 g DM m−2 of snag surface). The most productive stoneflies were Perlesta (0.7–1.0 g DM m−2 of snag surface) and Paragnetina (1.0–1.3 g DM m−2 of snag surface). The most productive dragonfly was Neurocordulia (0.7–1.9 g DM m−2 of snag surface). Production of the non‐predaceous stoneflies was 1.0–2.3 g DM m−2 of snag surface. Production values per m2 of river bed were 2–3.5 times lower than the values per m2 snag surface. 4. Measurement of ingestion fluxes within the predator portion of the food web showed that predaceous invertebrates were primarily supported by chironomid and mayfly prey. However, the greatest consumption of chironomids and mayflies was by omnivorous hydropsychid caddisflies, which had a considerably higher production than the larger predators. There was a hierarchy of feeding with Corydalus as top predator consuming all other groups, followed in order by dragonflies, stoneflies and hydropsychids. Although the feeding hierarchy suggested the presence of four predatory trophic levels within the invertebrate assemblage, calculations of trophic position indicated there were less than two. With primary consumers (e.g. midges) having a trophic position of 2, Corydalus had a trophic position of only 3.5. 5. A relatively high fraction of invertebrate production was consumed by predaceous invertebrates, ranging from 9 to &gt;100% for various primary consumer groups, with total consumption representing 52% of total production. Because these estimates do not include vertebrate consumption or emergence, it means that a high fraction of larval mortality is due to predation.

Interplay between dispersal determinants of larval hydropsychid caddisflies

We examined the interactive effects of predator (perlid stoneflies) presence, epilithic algal cover, and substrate size on drift and resettlement decisions by larval hydropsychid caddisflies in a series of experiments conducted in real and artificial streams. Predator effects on drift-entry depended on algal structural complexity. Stoneflies significantly increased hydropsychid drift from biofilm-covered rocks but not from rocks covered with a thick periphyton mat or with a macroalga (Cladophora glomerata, approx. 20% surface cover). When we manipulated degree of Cladophora cover, we found that Cladophora even in small amounts (4-13% cover) nullified stonefly effects on drift and that drift was inversely related to amount of Cladophora on rocks. However, Cladophora may only be important as a dispersal determinant until retreats (i.e., immovable cases) are constructed and vulnerability to predators decreases. Hydropsychid drift rates were positively related to gravel abundance, but Cladophora presence enhanced settlement rates on the substrate. Our study shows that multiple factors jointly influence dispersal patterns of hydropsychid larvae and that the relative strength of any one factor as a dispersal determinant varies depending on conditions of other determinants.

The Role of Stoneflies in Enhancing Growth of Trout: A Test of the Importance of Predator-Predator Facilitation within a Stream Community

Failure to understand subtle behavioral mechanisms can lead to mischaracterization of interactions within food webs. Laboratory studies indicating increased prey capture by fish when predatory invertebrates are present suggested a field experiment to evaluate the effect of stonefly removal on growth rate of fish. Individually marked juvenile cutthroat trout (Oncorynchus clarki) were introduced into replicate experimental stream channels beside a coastal Pacific rainforest stream. In stream channels with large perlid stoneflies (Doroneuria and Calineuria sp.) trout gained mass, whereas in channels without stoneflies trout lost body mass. There was no significant effect of stoneflies on trout mortality over the month-long experiments. Although total predator number and biomass were higher in channels with stoneflies (trout and stonefly biomass combined), trout apparently gained more from the way prey behavior was altered by the presence of stoneflies, than they lost from any effects of competition for common prey resources. The presence of significant facilitation amongst predators complicates our view of trophic structuring in stream communities, requiring that such non-intuitive interactions be more explicitly considered both by modelers and experimentalists seeking to evaluate the role of predators in these and in other communities.

Embryogenesis of Dinocras cephalotes, Perla grandis and P. marginata (Plecoptera: Perlidae) in different temperature regimes

1. Temperature dependence of embryogenesis of the three perlid stoneflies Dinocras cephalots, Perla grandis and P. marginata was investigated by means of incubation experiments. Special emphasis was laid on the effect of fluctuating temperatures and on intraspecific differences between populations from two different field sites in the Swiss prealps (i.e. River Necker and River Thur).2. Dinocras cephalotes embryos develop between 6.3 and 26.6 °C. The lower threshold temperature is lower than has been reported for more northern populations (i.e. from England and Norway), indicating the existence of a latitudinal gradient. Perla grandis eggs only developed between 9.9 and 18.4 °C. In P. marginata, successful embryogenesis was observed between 9.9 and 18.4 °C, but not enough eggs were available to explore the threshold temperatures.3. Embryogenesis of D. cephalotes and P. grandis was significantly faster at a 12/16 °C daily fluctuating temperature regime than at a constant 14 °C. However, no significant difference was found between the development under simulated field temperature regimes (with less distinct daily amplitudes) and constant temperatures.4. D. cephalotes, hatching of eggs from the Necker population was much less synchronous than that in the Thur population. Since the Necker discharge regime is harsher than the Thur regime, it is possible that this asynchrony spreads the risk of destruction during bed‐moving floods.

Benthic assemblages in Utah headwater streams with and without trout

In a series of high-gradient streams along the Wasatch Front in northern Utah, perlid stoneflies were more abundant in benthic samples from 14 fishless streams than in 9 similar streams which contained trout. Smaller-bodied perlodid stoneflies were more abundant in samples from streams containing trout. Herbivorous insect abundances varied substantially within groups of streams containing and lacking trout; multivariate analysis of variance using the six most abundant herbivorous taxa indicated no significant difference between the two groups of streams. Similarly, total numbers of invertebrates did not differ between streams with and without fish. Sites above and below the upstream limit of trout in three streams showed patterns in invertebrate abundances similar to that seen at the whole-stream scale. Trout may have no effect on the overall density of stream benthos because of their negative direct effects on invertebrate predators.

The effects of prey profitability and habitat complexity on the foraging success and growth of stonefly (Plecoptera) nymphs

SUMMARY The feeding behaviour of nymphs of the perlid stonefly Dinocras cephalotes when presented with two different mayfly prey types on different substrates was examined in the laboratory. Most of the evidence suggested that Dinocras cephalotes did not choose between Baetis rhodani and Rhithrogena semicolomta as, under identical circumstances: (i) the survival of both prey types was the same; (ii) the predator's overall searching behaviour was similar in the presence of either mayfly, although B. rhodani was pursued more, especially on complex substrates; (iii) the number of attacks on both prey types was the same; and (iv) the intake of dry weight prey biomass over 24 h remained the same, irrespective of prey species. The predation efficiency (no. of prey captured/no, of encounters) of D. cephalotes decreased with increasing substrate complexity—but only with R. semicolorata as prey, and also when more than one stonefly was present—but only when B. rhodani was the prey. Predator efficiency was greater at low densities of R. semicolorata but highest at a medium density of B. rhodani. Increase in the body weight of D. cephalotes was greater when nymphs were fed a monospecific diet of R. semicolorata compared with one of B. rhodani. This was despite the findings that: (i) nymphs of B. rhodani contained 31.3% more protein (per mg dry body weight) than nymphs of R. semicolorata, whereas the latter contained 81.0% more chitin; and (ii) nymphs of R. semicolorata took 2.7 times as long to consume and almost twice as long to pass through the predator's gut. The longer gut passage time may have allowed a greater assimilation efficiency which may have led to the observed better growth. Dinocras cephalotes is thought to feed opportunistically, with a certain daily food biomass intake as its primary need rather than any specific prey preference. Foraging decisions, or opportunities, affect the fitness of individual nymphs and this may be reflected in the wide size range of contemporary nymphs found in field populations. Variation in foraging efficiency by predators and evasion success by prey, across substrate types, is thought to contribute to the well‐known microdistribution patterns of species observed in lotic communities.

Relationship between Diurnal Activity Patterns, Cryptic Coloration, and Subsequent Avoidance of Predaceous Fish by Perlid Stoneflies

We demonstrate that prey (stoneflies), which are either solidly coloured or patterned, coordinate intervals of maximum daytime activity with periods when visually foraging predators (rainbow trout, Oncorhynchus mykiss) are least able to detect them. In this study, rainbow trout attacked solidly coloured stonefly nymphs (Paragnetina media) more frequently under conditions of low illumination (simulated dawn and dusk) than high illumination (simulated midday) whereas the frequency of attacks on patterned stonefly nymphs (Agnetina capitata) was reversed. Consequently, in both the presence and absence of trout, the activity (i.e. frequency of crawling) of P. media and A. capitata was highest under conditions of high and low illumination, respectively. The number of attacks by trout on all nymphs was significantly less when nymphs were on dark-brown, rather than mottled, substrates. When given a choice between dark-brown and mottled substrate, both species selected dark substrate. Suggestions that the visual acuity of predators varies as a function of light intensity and the coloration, patterning, and daytime activity of prey are corroborated for the first time.

Synergistic Interactions between Fish and Stoneflies: Facilitation and Interference among Stream Predators

A series of experiments examined rates of prey consumption by mottled sculpins (Cottus bairdi) and perlid stoneflies (Agnetina capitata) separately, and when they were together in artificial streams. Two types of Ephemeroptera prey (Ephemerella subvaria and Baetis tricaudatus) were used in separate experiments. When both types of predators were present consumption of Baetis larvae was significantly less than model predictions of combined prey consumption, indicating a negative interaction between predators. Consumption of Ephemerella was significantly higher than predicted by the model indicating a positive interaction between predators. Analysis of gut contents indicated that Agnetina captured fewer Baetis larvae in the presence of sculpins, and sculpins captured significantly more Ephemerella larvae in the presence of stoneflies. Negative effects of sculpins on the number of Baetis larvae captured by Agnetina were found even when the sculpins were unable to feed. Positive effects of Agnetina on the number of Ephemerella captured by sculpins were still found even when Agnetina density was reduced by more than half. Understanding the complexity of interaction between fish and stoneflies may provide explanations for the contradiction between observed and expected results of fish removal experiments in streams.