Stonefly Species Research Articles

Two new species of Indonemoura Baumann, 1975 (Plecoptera: Nemouridae) from southwestern China

Two new stonefly species of nemourid genus Indonemoura Baumann, 1975, I. hamilobata sp. n. and I. parallela sp. n., are described from southwestern China and their affinity to similar species is discussed.http://zoobank.org/urn:lsid:zoobank.org:pub:8936F040-5230-4E23-804D-702A12B019CD

An unusually large genome from an unusually large stonefly: a chromosome-length genome assembly for the giant salmonfly, Pteronarcys californica (Plecoptera: Pteronarcyidae).

Pteronarcys californica (Newport 1848) is commonly referred to as the giant salmonfly and is the largest species of stonefly (Insecta: Plecoptera) in the western United States. Historically, it was widespread and abundant in western rivers, but populations have experienced a substantial decline in the past few decades, becoming locally extirpated in numerous rivers in Utah, Colorado, and Montana. Although previous research has explored the ecological variables conducive to the survivability of populations of the giant salmonfly, a lack of genomic resources hampers exploration of how genetic variation is spread across extant populations. To accelerate research on this imperiled species, we present a de novo chromosomal-length genome assembly of P. californica generated from PacBio HiFi sequencing and Hi-C chromosome conformation capture. Our assembly includes 14 predicted pseudo chromosomes and 98.8% of Insecta universal core orthologs. At 2.40 gigabases, the P. californica assembly is the largest of available stonefly assemblies, highlighting at least 9.5-fold variation in assembly size across the order. Repetitive elements (REs) account for much of the genome size increase in P. californica relative to other stonefly species, with the content of Class I retroelements alone exceeding the entire assembly size of all but two other species studied. We also observed preliminary suborder-specific trends in genome size that merit testing with more robust taxon sampling.

Response of wild aquatic insect communities to thermal variation through comparative landscape transcriptomics.

Fluctuations in temperature are recognized as a potent driver of selection pressure, fostering genomic variations that are crucial for the adaptation and survival of organisms under selection. Notably, water temperature is a pivotal factor influencing aquatic organism persistence. By comprehending how aquatic organisms respond to shifts in water temperature, we can understand their potential physiological adaptations to environmental change in one or multiple species. This, in turn, contributes to the formulation of biologically relevant guidelines for the landscape scale transcriptome profile of organisms in lotic systems. Here, we investigated the distinct responses of seven stream stonefly species, collected from four geographical regions across Japan, to variations in temperature, including atmospheric and water temperatures. We achieved this by assessing the differences in gene expression through RNA-sequencing within individual species and exploring the patterns of community-genes among different species. We identified 735 genes that exhibited differential expressions across the temperature gradient. Remarkably, the community displayed expression levels differences of respiration and metabolic genes. Additionally, the diversity in molecular functions appeared to be linked to spatial variation, with water temperature differences potentially contributing to the overall functional diversity of genes. We found 22 community-genes with consistent expression patterns among species in response to water temperature variations. These genes related to respiration, metabolism and development exhibited a clear gradient providing robust evidence of divergent adaptive responses to water temperature. Our findings underscore the differential adaptation of stonefly species to local environmental conditions, suggesting that shared responses in gene expression may occur across multiple species under similar environmental conditions. This study emphasizes the significance of considering various species when assessing the impacts of environmental changes on aquatic insect communities and understanding potential mechanisms to cope with such changes.

Taxonomy and evolutionary implications of a new fossil stonefly family (Insecta, Plecoptera) from Middle Cretaceous Kachin amber of northern Myanmar

Plecoptera, commonly known as stoneflies, represent an ancient order of aquatic insects with significant ecological importance in freshwater ecosystems. This study describes a new genus and species of stonefly, Crossoperla teslenkoae n. gen. n. sp., based on a female adult preserved in Middle Cretaceous Kachin amber. Morphological examination reveals the taxonomic placement of C. teslenkoae within the infraorder Systellognatha of the suborder Arctoperlaria. Distinctive wing venation patterns and genitalic structures differentiate C. teslenkoae from extant and extinct stonefly families. A new extinct fossil family, Crossoperlidae n. fam. is established for the new stonefly. The findings contribute to the understanding of stonefly evolution, palaeodiversity, and ecological adaptations.

A new species and a newly record species of Amphinemurinae from Yunnan, China (Plecoptera, Nemouridae)

A new stonefly species of the genus Protonemura Kempny, 1898 of the subfamily Amphinemurinae, namely Protonemura potatsoensis Qian & Bai sp. nov., is described from Yunnan, southwestern China. Sphaeronemoura poda Sivec & Stark, 2010 is newly recorded for China. Detailed descriptions, photographs of genital characters and cervical gills features are presented.

Comparative larval morphology and DNA barcodes of Kamimuria petasus Chen and Neoperla tuberculata Wu (Plecoptera: Perlidae)

The larval morphology of Perlidae is relatively understudied compared to that of their adult counterparts, making it challenging to identify species using traditional morphological methods. In this study, we describe and illustrate the larvae of two stonefly species, Kamimuria petasus Chen, 2019 and Neoperla tuberculata Wu, 1937, based on specimens collected from China. Despite sharing a close resemblance in external morphology, the larvae of K. petasus and N. tuberculata can be distinguished based on their color pattern, chaetotaxy, and details of mouthparts. In addition, we generated and compared two DNA barcoding sequences for these two larvae. The analysis revealed that while the two species share some similar sequences, they exhibit high sequence divergence, which can be used to aid in the identification of the two different species based on immature material. The larval morphology and DNA barcodes provided in this study will supplement the classification of Perlidae larvae, enabling their more accurate and reliable identification in both full-evidence phylogenetic studies and bio-monitoring practices in the field.

Thermal tolerance of giant salmonfly nymphs (Pteronarcys californica) varies across populations in a regulated river.

Warming of aquatic ecosystems is transforming the distribution, phenology and growth of the organisms dependent upon these ecosystems. Aquatic insects such as stoneflies are especially vulnerable to warming because the aquatic nymph stage of their life cycle depends on cool, well-oxygenated, flowing water habitat. We tracked thermal effects on available aerobic capacity of the aquatic nymph stage of an iconic and vulnerable stonefly species, the giant salmonfly (Pteronarcys californica), to compare habitat thermal regime measurements for two salmonfly populations from habitats separated by a gradient in summer weekly maximum temperatures. Contrary to expectations, the thermal optima range of the warmer habitat population was cooler than for the cooler habitat population. We posit that this unexpected interpopulation variation in thermal response is more strongly driven by diel and seasonal thermal variability than by the highest summer temperatures experienced within respective habitats. Additionally, we show that summer daily maximum temperatures could result in periodic limits in available aerobic capacity to support work of the warmer habitat nymphs and may be the mechanism underlying reduced abundance relative to the upstream cooler habitat population. Our findings provide insight into potential thermal and metabolic mechanisms that could regulate the success of ecological and culturally important aquatic insect species experiencing global change. We conclude that thermal regimes and thermal variation, not just mean and maximum temperatures, are critical drivers of aquatic insect responses to water temperatures.

New records and distribution data of stoneflies (Insecta: Plecoptera) from the Western Balkans

The knowledge about stoneflies of the Balkan Peninsula is still not complete, with many areas poorly investigated. During this investigation, we collected adult stonefly specimens from Kosovo, Albania, North Macedonia, Serbia and Montenegro during the period 2014-2018. In total, we found 42 species belonging to 14 genera and 7 families. Five species are recorded for the first time for Kosovo (Leuctra cingulata Kempny, 1899, Leuctra cf. olympia Aubert, 1956 Nemoura cf. lucana Nicolai & Fochetti, 1991, Nemoura uncinata Despax, 1934 and Brachyptera macedonica Ikonomov, 1983), one is recorded for the first time for Serbia (Nemoura asceta Murányi, 2007) and one for Albania (Leuctra major Brinck, 1949). This investigation contributes to the knowledge of distribution patterns of stoneflies species in the Balkan Peninsula.

Isoperla riverae, a new stonefly species from the southeast Nearctic, with notes on sympatric species including the larval description of Isoperla lenati Szczytko & Kondratieff, 2015 (Plecoptera: Perlodidae).

Isoperla riverae sp. n. is described from the southeastern USA. The new species is proposed based on details of the adult habitus, male aedeagus, vesicle, female subgenital plate, ovum chorion, and larval habitus. Supporting data includes color images, scanning electron micrographs, genetic analysis of DNA barcodes, and comparative morphology of cognate species. The larva of Isoperla lenati Szczytko & Kondratieff, 2015 is also described supported by color images.

The First Study of Mating Mistakes in Stoneflies (Plecoptera) from China, with Remarks on Their Biological Implications.

Currently, information on the biology of Plecoptera from China is scarce, particularly on mating behavior. In this paper, the existence of mating mistakes (erroneous mating attempts) involving 13 Chinese stonefly species (belonging to nine genera and three families) is reported. These erroneous mating behaviors can be included into three different categories: mating attempts between conspecific males (including the formation of erroneous mating balls), mating attempts between different taxa (including displacement attempts during copulation), and mating-related behaviors with non-living objects. From these behaviors, some aspects of stoneflies during mating, such as the physical competition between males, the sensorial mechanisms implied in triggering a mating behavior, the conditions favoring the mating mistakes, and the possible consequences of interspecific mating in the hybrid production, are discussed.

Additions to the fauna and biology of stoneflies (Plecoptera) in Taizi River Basin, Liaoning, with seven new species records to China.

An investigation report of stonefly fauna in Benxi Manchu Autonomous County, Liaoning Province, northeast China (used to be called Manchuria, now includes Liaoning, Jilin, Heilongjiang Provinces and parts of Inner Mongolia, which are adjacent to the Russian Far East and the Korean Peninsula). Materials were studied with field observation in 2018 and 2019. This paper records five families, nine genera and 14 species of stoneflies from Taizi River, Liaoning Province. Nine species have been recorded for the first time in China and the biology of several common species is also reported for the first time.

Exposure to copper increases hypoxia sensitivity and decreases upper thermal tolerance of giant salmonfly nymphs (Pteronarcys californica)

Many aquatic insects are exposed to the dual stressors of heavy metal pollution and rising water temperatures from global warming. These stresses may interact and have stronger impacts on aquatic organisms if heavy metals interfere with the ability of these organisms to handle high temperatures. Here we focus on the effect of copper on upper thermal limits of giant salmonfly nymphs (Order: Plecoptera, Pteronarcys californica), a stonefly species which is common in parts of western North America. Experimental exposure to copper reduced upper thermal limits by ∼ 10 °C in some cases and depressed the hypoxia tolerance (Pcrit) of nymphs by ∼ 0.5 mg L−1 DO. These results suggest that copper inhibits the delivery of oxygen, which may explain, in part, the strong reductions in CTMAX that we report. Fluorescence microscopy of Cu-exposed individuals indicated high levels of copper in chloride cells but no clear evidence of damage to or high levels of copper on the gills themselves. Our study indicates that populations of aquatic insects from copper-polluted environments may be further at risk to future warming than those from uncontaminated environments.

Species of Nemoura (Plecoptera: Nemouridae) from Qinghai, China.

A new species of forest stonefly, Nemoura jixiangwangi Yang Li, sp. nov., is described and compared with related taxa, based on specimens from the Qilian Mountain National Park, Qinghai Province, northwestern China. Nemoura geei Wu, 1929, Nemoura papilla Okamoto, 1922 and Nemoura securigera Klaplek, 1907 are recorded from the province and the mountain range for the first time.

A description of the male drumming call of Besdolus ventralis (Pictet, 1841) (Plecoptera: Perlodidae)

This paper gives the first description of the male drumming call of Besdolus ventralis. Based on the examination of a single male specimen of this rare stonefly species its male call is composed of 3 beat groups, each containing 3-6 beats repeated at decreasing interbeat intervals. Beat groups are separated by 184-212 ms intergroup intervals. Call duration varied between 496-549 ms at ambient air temperature 18.7-20.4 degrees of Celsius. These results show that the male call of B. ventralis is clearly different from the diphasic call of B. ravizzarum, and is rather similar to that of B. bicolor, which is the closest relative of B. ventralis regarding mitocondrial DNA sequences. The main difference between the male calls of the two species seems to be that B. ventralis produces 3-6 beats per group, while B. bicolor is reported to produce only 2 (rarely 3) beats per beat-group.

Landscape Connectivity and Genetic Structure in a Mainstem and a Tributary Stonefly (Plecoptera) Species Using a Novel Reference Genome.

Understanding how environmental variation influences population genetic structure can help predict how environmental change influences population connectivity, genetic diversity, and evolutionary potential. We used riverscape genomics modeling to investigate how climatic and habitat variables relate to patterns of genetic variation in 2 stonefly species, one from mainstem river habitats (Sweltsa coloradensis) and one from tributaries (Sweltsa fidelis) in 40 sites in northwest Montana, USA. We produced a draft genome assembly for S. coloradensis (N50 = 0.251 Mbp, BUSCO > 95% using "insecta_ob9" reference genes). We genotyped 1930 SNPs in 372 individuals for S. coloradensis and 520 SNPs in 153 individuals for S. fidelis. We found higher genetic diversity for S. coloradensis compared to S. fidelis, but nearly identical genetic differentiation among sites within each species (both had global loci median FST = 0.000), despite differences in stream network location. For landscape genomics and testing for selection, we produced a less stringently filtered data set (3454 and 1070 SNPs for S. coloradensis and S. fidelis, respectively). Environmental variables (mean summer precipitation, slope, aspect, mean June stream temperature, land cover type) were correlated with 19 putative adaptive loci for S. coloradensis, but there was only one putative adaptive locus for S. fidelis (correlated with aspect). Interestingly, we also detected potential hybridization between multiple Sweltsa species which has never been previously detected. Studies like ours, that test for adaptive variation in multiple related species are needed to help assess landscape connectivity and the vulnerability of populations and communities to environmental change.

A new stonefly from mid-Cretaceous Kachin amber reveals novel genital structure for the extinct genus Largusoperla (Plecoptera: Perlidae)

Largusoperla zhouchangfai sp. nov., a new extinct stonefly species is described based on a male adult in mid-Cretaceous Kachin amber. The new stonefly exhibits well-preserved wing pairs, dorsal and ventral abdominal segments and aedeagus. The new species is inter alia characterized by the two elongated lobes on the cleft tergum 10, inverted V-shaped epiproct sclerite, small circular hammer, subtriangular paraprocts, and the tubular aedeagus with three slender apical spines. Morphological characters of the new species are described, illustrated, and compared with related taxa.

Stoneflies (Plecoptera) of the Moravskoslezské Beskydy Mts. and the Podbeskydská pahorkatina Uplands, Czech Republic. I. Systellognatha

Abstract Publications up to 2011 record 21 species of stonefly, infraorder Systellognatha, as occurring in the Moravskoslezské Beskydy Mts. and Podbeskydská pahorkatina Uplands; however, seven of these cannot be considered part of the fauna of this area as they probably never occurred there, and one species (Perla abdominalis Burmeister, 1839) was not confirmed, despite being demonstrably recorded in 2000. In the present study, the current stonefly fauna was confirmed at 14 species, belonging to three families and eight genera. The occurrence of Isoperla sudetica (Kolenati, 1859) is published for the first time. Among the most important findings are confirmation of the occurrence of two endangered species (Perla grandis (Rambur, 1841) and Arcynopteryx dichroa (McLachlan, 1872)) and one near threatened species (Isoperla buresi Raušer, 1962). Equally important is confirmation of the occurrence of Perlodes intricatus (Pictet, 1841), based on egg morphology and DNA barcoding.

A new mid-Cretaceous fossil genus of stonefly (Plecoptera: Perlidae) from the Burmese amber

A new genus and species of stonefly is described and figured from the mid-Cretaceous Burmese amber as †Burmaperla pouilloni Jouault & Nel gen. et sp. nov. The placement of this new genus and species within the Perlidae is corroborated by an in-depth comparison of apomorphies. This new species differs from all other Acroneuriinae from the mid-Cretaceous Burmese amber biota, inter alia, owing to its wing venation with ScP reaching RA beyond ra-rp, RP with three branches, MP partially fused with the upper branch of CuA, CuA with four branches, its hammer nearly circular and its genitalia with paraprocts weakly sclerotized, abruptly upcurved, thinning towards the apex and symmetrical. This new species increases the diversity of Acroneuriinae stoneflies in the Burmese amber biota, and combined with the geological history of the Burmese terrane is used to discuss the putative presence of Antarctoperlaria in mid-Cretaceous Burmese amber.

New faunistic data on the family Capniidae (Plecoptera) from the Carpathians (Romania and Ukraine)

Zwicknia acuta is reported for the first time from the South-Eastern Carpathians (Romania and Ukraine). Additionally, another stonefly species, Zwicknia kovacsi, previously described from Romania, is added to the Plecoptera fauna of Ukraine. New faunistic data are presented for two other winter-active species, Capnia vidua rilensis and Zwicknia bifrons. Based on a combination of personal and literature data we present a checklist of Capniidae from Romania and provide a key for them.

The concept of ecological integrity may have been useful, but that does not make it real or morally valuable

In response to our article arguing that ecological integrity is neither real nor morally valuable (Rohwer & Marris, 2021), Karr et al. (2021) defend the concept of ecological integrity for its pragmatic success and intuitive appeal. We understand their attachment to a term that has no doubt felt useful to them, but we simply do not think it worth retaining as a “useful fiction” when there are defensible, specific, and measurable values that could be used more directly and more clearly. The authors argue that the construct “ecological integrity” has “led to many real-world accomplishments in river and water resource protection and later, to assessing and conserving diverse environments (freshwater, marine, wetland, and terrestrial)” (Karr et al., 2021, p. 2). We do not doubt this. In fact, we admitted as much in our piece, writing that “Where it is used as a rough proxy for complexity, diversity, and preferred historic states, it may not lead us astray in the short term” (Rohwer & Marris, 2021, p. 9). But we added a primary concern: that “where actions to protect or promote ‘integrity’ prompt us to stop ecosystems from adapting in the face of change, we may find ourselves unwittingly compromising other values we hold dear, including biodiversity” (Rohwer & Marris, 2021, p. 9). We stand by this concern. The fact that interventions taken in the name of ecological integrity have led to positive outcomes is not a convincing argument for the existence of ecological integrity. When sewers were installed in cities to combat disease because of a belief that poor sanitation created unhealthy “miasmas,” lives were undoubtedly saved, since the action had the effect of destroying habitats for deadly bacteria. Those saved lives do not prove the existence of miasma (Whorton, 2001). The authors argue that “the concept of ecological integrity—particularly, biological integrity—can be and has been translated into measurable, practicable criteria for protecting living ecosystems” (Karr et al., 2021, p?). But then why bother with the translation? Why not simply start with the measurable criteria themselves? Karr et al. appeal to intuition. “Surely,” they write, “we can agree that value is lost if a stream community harboring multiple species of mayflies, stoneflies, and caddisflies is replaced—for example, downstream of a waste treatment plant—by a community dominated by sewage sludge worms” (Karr et al., 2021, p. 2). We can agree to this! But it proves our point. The loss of value here can be captured by the specific values of biodiversity and complexity. “Integrity” is not required. The authors tout the “multimetric framework” of the index of biological integrity as a virtue. To us, this amalgamation of biodiversity measures with metrics for anthropocentric values like “fishable and swimmable” waters also proves our point: integrity is usually a proxy for biodiversity, complexity, and culturally preferred states. So why not simply say what we mean rather than using the word “integrity” inconsistently and often incoherently to try to refer to the many ways that ecosystems can be valuable? The authors say that they define integrity as “one endpoint on a gradient of biological conditions, ranging from relatively free of human disturbance to nothing left alive” (Karr et al., 2021, p. 4). Is this not simply another way of saying naturalness? If that is what they value, they should just say so. The authors seem to worry that discarding the word “integrity,” will leave no way to set conservation or restoration goals or to measure success or failure. We disagree. By speaking plainly about what we value and why, whether that be a certain suite of beloved species or a certain measure of biodiversity, we are actually better poised to achieve our goals. Progress toward these goals is easily measured—often with the same exact data we are currently collecting to measure “integrity.” If you want your river to have clean water, lots of fish, and specific native fish, just say so. You do not need the pseudo-objective term “integrity,” which ultimately obfuscates more than it clarifies. The authors declare no potential conflict of interest. Data sharing is not applicable to this article as no new data were created or analyzed in this study.