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.

A phylogenomic perspective on the evolutionary history of the stonefly genus Suwallia (Plecoptera: Chloroperlidae) revealed by ultraconserved genomic elements.

Evolutionary biologists have long sought to disentangle phylogenetic relationships among taxa spanning the tree of life, an increasingly important task as anthropogenic influences accelerate population declines and species extinctions, particularly in insects. Phylogenetic analyses are commonly used to identify unique evolutionary lineages, to clarify taxonomic designations of the focal taxa, and to inform conservation decisions. Advances in DNA sequencing techniques have increasingly facilitated the ability of researchers to apply genomic methods to phylogenetic analyses, even for non-model organisms. Stoneflies are non-model insects that are important bioindicators of the quality of freshwater habitats and landscape disturbance as they spend the immature stages of their life cycles in fresh water, and the adult stages in terrestrial environments. Phylogenetic relationships within the stonefly genus Suwallia (Insecta: Plecoptera: Chloroperlidae) are poorly understood, and have never been assessed using molecular data. We used DNA sequence data from genome-wide ultraconserved element loci to generate the first molecular phylogeny for the group and assess its monophyly. We found that Palearctic and Nearctic Suwallia do not form reciprocally monophyletic clades, and that a biogeographic history including dispersal, vicariance, and founder event speciation via jump dispersal best explains the geographic distribution of this group. Our results also strongly suggest that Neaviperla forcipata (Neave, 1929) is nested within Suwallia, and the concept of the genus Suwallia should be revised to include it. Thus, we formally propose a new taxonomic combination wherein Neaviperla forcipata (Neave, 1929) is reclassified as Suwallia forcipata (Neave, 1929). Moreover, some Suwallia species (e.g., S. amoenacolens, S. kerzhneri, S. marginata, S. pallidula, and S. starki) exhibit pronounced cryptic diversity that is worthy of further investigation. These findings provide a first glimpse into the evolutionary history of Suwallia, improve our understanding of stonefly diversity in the tribe Suwallini, and highlight areas where additional research is needed.

Genomic signatures of parallel alpine adaptation in recently evolved flightless insects.

Natural selection along elevational gradients has potential to drive predictable adaptations across distinct lineages, but the extent of such repeated evolution remains poorly studied for many widespread alpine taxa. We present parallel genomic analyses of two recently evolved flightless alpine insect lineages to test for molecular signatures of repeated alpine adaptation. Specifically, we compare low-elevation vs. alpine stonefly ecotypes from parallel stream populations in which flightless upland ecotypes have been independently derived. We map 67,922 polymorphic genetic markers, generated across 176 Zelandoperla fenestrata specimens from two independent alpine stream populations in New Zealand's Rock and Pillar Range, to a newly developed plecopteran reference genome. Genome-wide scans revealed 31 regions with outlier single nucleotide polymorphisms (SNPs) differentiating lowland vs. alpine ecotypes in Lug Creek, and 37 regions with outliers differentiating ecotypes in Six Mile Creek. Of these regions, 13% (8/60) yielded outlier SNPs across both within-stream ecotype comparisons, implying comparable genomic shifts contribute to this repeated alpine adaptation. Candidate genes closely linked to repeated outlier regions include several with documented roles in insect wing-development (e.g., dishevelled), suggesting that they may contribute to repeated alpine wing reduction. Additional candidate genes have been shown to influence insect fecundity (e.g., ovo) and lifespan (e.g., Mrp4), implying that they might contribute to life history differentiation between upland and lowland ecotypes. Additional outlier genes have potential roles in the evolution of reproductive isolation among ecotypes (hedgehog and Desaturase 1). These results demonstrate how replicated outlier tests across independent lineages can potentially contribute to the discovery of genes underpinning repeated adaptation.

Tolerance of aquifer stoneflies to repeated hypoxia exposure and oxygen dynamics in an alluvial aquifer.

Aquatic insects cope with hypoxia and anoxia using a variety of behavioral and physiological responses. Most stoneflies (Plecoptera) occur in highly oxygenated surface waters, but some species live underground in alluvial aquifers containing heterogeneous oxygen concentrations. Aquifer stoneflies appear to be supported by methane-derived food resources, which they may exploit using anoxia-resistant behaviors. We documented dissolved oxygen dynamics and collected stoneflies over 5 years in floodplain wells of the Flathead River, Montana. Hypoxia regularly occurred in two wells, and nymphs of Paraperla frontalis were collected during hypoxic periods. We measured mass-specific metabolic rates (MSMRs) at different oxygen concentrations (12, 8, 6, 4, 2, 0.5 mg l-1, and during recovery) for 111 stonefly nymphs to determine whether aquifer and benthic taxa differed in hypoxia tolerance. Metabolic rates of aquifer taxa were similar across oxygen concentrations spanning 2 to 12 mg l-1 (P>0.437), but the MSMRs of benthic taxa dropped significantly with declining oxygen (P<0.0001; 2.9-times lower at 2 vs. 12 mg l-1). Aquifer taxa tolerated short-term repeated exposure to extreme hypoxia surprisingly well (100% survival), but repeated longer-term (>12 h) exposures resulted in lower survival (38-91%) and lower MSMRs during recovery. Our work suggests that aquifer stoneflies have evolved a remarkable set of behavioral and physiological adaptations that allow them to exploit the unique food resources available in hypoxic zones. These adaptations help to explain how large-bodied consumers might thrive in the underground aquifers of diverse and productive river floodplains.

Complex and nonlinear climate-driven changes in freshwater insect communities over 42 years.

The ongoing biodiversity crisis becomes evident in the widely observed decline in abundance and diversity of species, profound changes in community structure, and shifts in species' phenology. Insects are among the most affected groups, with documented decreases in abundance up to 76% in the last 25-30 years in some terrestrial ecosystems. Identifying the underlying drivers is a major obstacle as most ecosystems are affected by multiple stressors simultaneously and in situ measurements of environmental variables are often missing. In our study, we investigated a headwater stream belonging to the most common stream type in Germany located in a nature reserve with no major anthropogenic impacts except climate change. We used the most comprehensive quantitative long-term data set on aquatic insects available, which includes weekly measurements of species-level insect abundance, daily water temperature and stream discharge as well as measurements of additional physicochemical variables for a 42-year period (1969-2010). Overall, water temperature increased by 1.88 °C and discharge patterns changed significantly. These changes were accompanied by an 81.6% decline in insect abundance, but an increase in richness (+8.5%), Shannon diversity (+22.7%), evenness (+22.4%), and interannual turnover (+34%). Moreover, the community's trophic structure and phenology changed: the duration of emergence increased by 15.2 days, whereas the peak of emergence moved 13.4 days earlier. Additionally, we observed short-term fluctuations (<5 years) in almost all metrics as well as complex and nonlinear responses of the community toward climate change that would have been missed by simply using snapshot data or shorter time series. Our results indicate that climate change has already altered biotic communities severely even in protected areas, where no other interacting stressors (pollution, habitat fragmentation, etc.) are present. This is a striking example of the scientific value of comprehensive long-term data in capturing the complex responses of communities toward climate change.

Cambios Complejos y No Lineales Causados por el Clima en Comunidades de Insectos de Agua Dulce durante 42 Años Resumen La continua crisis de la biodiversidad se vuelve evidente en la ampliamente documentada declinación en la abundancia y diversidad de especies, cambios profundos en la estructura de las comunidades y modificaciones en la fenología de las especies. Los insectos se encuentran entre los grupos más afectados; se han documentado reducciones en la abundancia de hasta el 76% en los últimos 25-30 años en algunos ecosistemas terrestres. La identificación de los causantes subyacentes es un gran obstáculo porque la mayoría de los ecosistemas están afectados por varios factores estresantes simultáneamente y con frecuencia faltan las medidas in situ de las variables ambientales. Investigamos un flujo naciente perteneciente al tipo de arroyo más común en Alemania ubicado dentro de una reserva natural sin impactos antropogénicos importantes a excepción del cambio climático. Usamos el conjunto más completo disponible de datos cuantitativos de largo plazo para insectos acuáticos que incluye las medidas semanales de abundancia de insectos a nivel especie, las medidas diarias de la temperatura del agua y la descarga del flujo y las medidas de variables físico-químicas adicionales durante 42 años (1969 - 2010). En general, la temperatura del agua incrementó 1.88°C y los patrones de descarga cambiaron significativamente. Estos cambios estuvieron acompañados por una declinación del 81.6% en la abundancia de insectos, pero también de un incremento en la riqueza (+8.5%), la diversidad Shannon (+22.7%), la uniformidad (+22.4%) y la renovación interanual (+34%). Además, la estructura trófica y la fenología de la comunidad cambiaron: la duración del surgimiento incrementó en 15.2 días y el pico del surgimiento ocurrió con 13.4 días de anticipación. Observamos fluctuaciones a corto plazo (<5 años) en casi todas las medidas, así como respuestas complejas y no lineales de la comunidad hacia el cambio climático que podrían haber sido ignoradas si sólo se usaran datos instantáneos o series de tiempo más cortas. Nuestros resultados indican que el cambio climático ya ha alterado seriamente a las comunidades bióticas, incluso en áreas protegidas en las que no están presentes otros factores estresantes en interacción (contaminación, fragmentación del hábitat, etc.). Ésto es un ejemplo notable del valor científico que tienen los datos completos de escalas de tiempo a largo plazo para la captura de las respuestas complejas de las comunidades ante el cambio climático.

Changes in species composition of water insects during 25-year monitoring of the Danube floodplains affected by the Gabcíkovo waterworks.

This study was based on the complex environmental monitoring of the Danube River in Slovakia. Out of 23 monitored sites, three were chosen for the aim of this study. The three sites were sampled regularly three times per year during a 25-year period, which started in 1990, 2 years before the Gabcíkovo waterworks became operational. Each site represented one of the main potamal types, which we recognised according to the habitat characteristics as eupotamal, parapotamal and plesiopotamal. In order to assess changes which occurred during the 25 years, we studied taxocoenoses of Ephemeroptera, Plecoptera and Trichoptera, which sensitively reflect anthropogenic impacts. The changes caused by the Gabcíkovo waterworks manifested in a decrease of the species diversity in eupotamal because of the disappearance of rheophilous taxa. In the parapotamal and plesiopotamal sites, the initial decrease was followed by a partial recovery of biodiversity due to the artificial floodings. After they were stopped, the decrease occurred again and until 2015, the insect taxa became rare. Conversely, in the eupotamal site, there was an increasing trend in biodiversity since 2011 until 2015. Overall increase in the floodplain index values indicated a loss of connectivity between the floodplain habitats and their fauna with the main channel during the last 25 years. In this paper, we also extended the floodplain index with data on habitat values and indication weight for several stonefly species.

Climate-induced glacier and snow loss imperils alpine stream insects.

Climate warming is causing rapid loss of glaciers and snowpack in mountainous regions worldwide. These changes are predicted to negatively impact the habitats of many range-restricted species, particularly endemic, mountaintop species dependent on the unique thermal and hydrologic conditions found only in glacier-fed and snow melt-driven alpine streams. Although progress has been made, existing understanding of the status, distribution, and ecology of alpine aquatic species, particularly in North America, is lacking, thereby hindering conservation and management programs. Two aquatic insects - the meltwater stonefly (Lednia tumana) and the glacier stonefly (Zapada glacier) - were recently proposed for listing under the U.S. Endangered Species Act due to climate-change-induced habitat loss. Using a large dataset (272 streams, 482 total sites) with high-resolution climate and habitat information, we describe the distribution, status, and key environmental features that limit L. tumana and Z. glacier across the northern Rocky Mountains. Lednia tumana was detected in 113 streams (175 sites) within Glacier National Park (GNP) and surrounding areas. The probability of L. tumana occurrence increased with cold stream temperatures and close proximity to glaciers and permanent snowfields. Similarly, densities of L. tumana declined with increasing distance from stream source. Zapada glacier was only detected in 10 streams (24 sites), six in GNP and four in mountain ranges up to ~600 km southwest. Our results show that both L. tumana and Z. glacier inhabit an extremely narrow distribution, restricted to short sections of cold, alpine streams often below glaciers predicted to disappear over the next two decades. Climate warming-induced glacier and snow loss clearly imperils the persistence of L. tumana and Z. glacier throughout their ranges, highlighting the role of mountaintop aquatic invertebrates as sentinels of climate change in mid-latitude regions.

First Mitochondrial Genome from Nemouridae (Plecoptera) Reveals Novel Features of the Elongated Control Region and Phylogenetic Implications.

The complete mitochondrial genome (mitogenome) of Nemoura nankinensis (Plecoptera: Nemouridae) was sequenced as the first reported mitogenome from the family Nemouridae. The N. nankinensis mitogenome was the longest (16,602 bp) among reported plecopteran mitogenomes, and it contains 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes and two ribosomal RNA (rRNA) genes. Most PCGs used standard ATN as start codons, and TAN as termination codons. All tRNA genes of N. nankinensis could fold into the cloverleaf secondary structures except for trnSer (AGN), whose dihydrouridine (DHU) arm was reduced to a small loop. There was also a large non-coding region (control region, CR) in the N. nankinensis mitogenome. The 1751 bp CR was the longest and had the highest A+T content (81.8%) among stoneflies. A large tandem repeat region, five potential stem-loop (SL) structures, four tRNA-like structures and four conserved sequence blocks (CSBs) were detected in the elongated CR. The presence of these tRNA-like structures in the CR has never been reported in other plecopteran mitogenomes. These novel features of the elongated CR in N. nankinensis may have functions associated with the process of replication and transcription. Finally, phylogenetic reconstruction suggested that Nemouridae was the sister-group of Capniidae.

Physiological strategies contributing to the coexistence of two predatory species of stoneflies: Dinocras cephalotes and Perla bipunctata.

Our study focuses on the oxidative state of two aquatic insects of the order Plecoptera belonging to the family Perlidae, namely Dinocras cephalotes (Curtis, 1827) and Perla bipunctata Pictet, 1833. These species are widely distributed throughout the Western Palearctic region and coexist in the stream where individuals for this study come from. We highlight the physiological strategies of these two different predator species of stoneflies, showing a higher accumulation of lipid reserves in P. bipunctata, higher glucose levels in the body tissues of D. cephalotes and a higher capacity of the antioxidant enzymes in P. bipunctata, what provides it a protection against oxidation of lipids, which are greater in this species. This leads to a similar oxidative state in both species. Based on these results is discussed how two close related species developing a very similar ecological role in the same habitat can achieve a similar fitness with differences in their physiological strategies.

New species of Paramoebidium (trichomycetes, Mesomycetozoea) from the Mediterranean, with comments about the amoeboid cells in Amoebidiales.

Paramoebidium, along with Amoebidium, constitute the order Amoebidiales, traditionally included in the ecological group trichomycetes and conventionally studied by mycologists, although they are phylogenetically embedded in the protist clade Mesomycetozoean (Ichthyosporea). The genus Paramoebidium has 13 accepted species, all associated with immature stages of aquatic insects. Three new species of Paramoebidium, P. angulatum, P. avitruviense and P. ecdyonuridaei, are described here, associated with either Plecoptera and Ephemeroptera nymphs. During routine observations of the amoeboid phases, uroidal adhesive filaments at the posterior end of the amoebae were noted and photographed, this being a novel observation for the Amoebidiales. This and other features are illustrated for all taxa.

A comprehensive DNA barcoding reference database for Plecoptera of Switzerland.

DNA barcoding is an essential tool in modern biodiversity sciences. Despite considerable work to barcode the tree of life, many groups, including insects, remain partially or totally unreferenced, preventing barcoding from reaching its full potential. Aquatic insects, especially the three orders Ephemeroptera, Plecoptera, and Trichoptera (EPT), are key freshwater quality indicators worldwide. Among them, Plecoptera (stoneflies), which are among the most sensitive aquatic insects to habitat modification, play a central role in river monitoring surveys. Here, we present an update of the Plecoptera reference database for (meta)barcoding in Switzerland, now covering all 118 species known from this country. Fresh specimens, mostly from rare or localized species, were collected, and 151 new CO1 barcodes were generated. These were merged with the 422 previously published sequences, resulting in a dataset of 573 barcoded specimens. Our CO1 dataset was delimited in 115 CO1 clusters based on a priori morphological identifications, of which 17% are newly reported for Switzerland, and 4% are newly reported globally. Among the 115 CO1 clusters, 85% showed complete congruence with morphology. Distance-based analysis indicated local barcoding gaps in 97% of the CO1 clusters. This study significantly improves the Swiss reference database for stoneflies, enhancing future species identification accuracy and biodiversity monitoring. Additionally, this work reveals cryptic diversity and incongruence between morphology and barcodes, both presenting valuable opportunities for future integrative taxonomic studies. Voucher specimens, DNA extractions and reference barcodes are available for future developments, including metabarcoding and environmental DNA surveys.

Sperm models in European Plecoptera.

Systematic issues regarding Plecoptera are still debated, and the molecular data seem to be unable to definitively clarify the relationships within the order. Spermatozoa are under constant evolutionary pressure, and comparative spermatology can be useful in carrying systematic and phylogenetic information. In the present paper we describe the sperm structure, using light, scanning and transmission electron and immunofluorescence microscopy, of six Euholognatha species belonging to genera not analyzed in our previous studies, i.e. Capnopsis, Amphinemura, Rhabdiopteryx, Tyrrhenoleuctra, Zwicknia and Protonemura. The spermatozoa of all the species examined are fîliform and have a flagellum characterized by an axoneme with 9 + 9+2 pattern and two mitochondrial derivatives. Their ultrastructure shows a degree of heterogeneity within the order. On the contrary, morphological features of sperm are well conserved inside a single Euholognathan family, and the species share a general family sperm model, even if different interspecific or intergeneric characters can be identified and used for systematic inferences. Among Nemouroidea, Taeniopterygidae, showing a peculiar sperm model, seems to have an isolated phylogenetic position. Nemouridae, with a mono-layered acrosome, are isolated among the remaining families, while we can hypothesize a sister taxa relationship between Leuctridae and Capniidae. As regards Perloidea, the sperm characters suggest a closer relationship between Chloroperlidae and Perlodidae, rather than between Perlidae and Perlodidae, as commonly hypothesized.

Taxonomic Contributions on Macrogynoplax Enderlein and Enderleina Jewett (Plecoptera: Perlidae) from Brazil, Including a New Species Supported by Molecular and Morphological Data.

Stoneflies (Plecoptera) are aquatic insects widely used in ecological and monitoring studies as indicators of environmental quality due to their high sensitivity to pollution. Among Brazilian Plecoptera, Perlidae is the most diverse family, with four genera (Anacroneuria Klapálek 1909, Enderleina Jewett 1960, Kempnyia Klapálek 1914, and Macrogynoplax Enderlein 1909) and about 150 species. Herein, based on data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene and morphological characters, we studied specimens of Enderleina and Macrogynoplax, mainly from the Brazilian Savanna. Our alignment with a total length of 608 base pairs included 23 COI sequences, of which 10 are new and 13 were obtained from GenBank. The sequences and congruence of the obtained species clusters were analyzed using neighbor joining. As a result, we describe a new species of Enderleina, the first of this genus in the Brazilian Savanna, and update the geographic distribution of some Macrogynoplax species. A new record was included for Macrogynoplax veneranda Froehlich 1984 in São Paulo state and the first record of M. yupanqui Stark 1996 in Brazil was also included. First records were made for Macrogynoplax matogrossensis Bispo and Neves 2005 and a Macrogynoplax specimen in Goiás and Bahia states, respectively. Consequently, we expanded the distribution of the genus in the Brazilian Savanna and Atlantic Forest. In addition, we provide observations on the morphological differences found among these species, discuss about the distribution of the genera, present molecular data discussing their contributions to the knowledge of the genus, and comment on the recommendations for future research considering a scenario of integrative approaches. Lastly, we present a key to identify the adult males of Enderleina.

A new species of Sweltsa Ricker, 1943 (Plecoptera, Chloroperlidae) and a supplementary description of Sweltsahamula Chen & Du, 2017 from China.

Background: The genus Sweltsa is a small to medium-sized stonefly with distinct coloured wings, giving the species the common name of green stoneflies. It belongs to the family Chloroperlidae. This genus includes more than 55 species world wide, 14 of which have been reported from China. New information: A new species of the genus Sweltsa Ricker, 1943, Sweltsaliupanshana Rehman, Du & Huo sp. nov. from Ningxia Hui Autonomous Region, Liupan Mountain, China is described; this is the second record of Sweltsa from Ningxia Hui Autonomous Region. In addition, the first female description and male supplementary description of Sweltsahamula Chen & Du, 2017 from Sichuan Province are provided. Diagnosis, description and colour illustration of the new species and of Sweltsahamula are provided and the morphological characteristics are compared with closely-related species.

Two new species and records of Neoperla (Plecoptera, Perlidae) from Yunnan, China.

Two new species of the stonefly genus Neoperla, N.gaoligongshana sp. nov. and N.hajeki sp. nov. are described from Yunnan Province of southwestern China based on the morphological and distributional data, and the new species are compared with two congeners, N.wuzhishana Chen & Du, 2016 and N.orissa Stark & Sivec, 2015. Neoperlahubleyi Stark & Sivec, 2008 is recorded from Yunnan Province for the first time.

Two new species and one new record of Neoperla (Plecoptera, Perlidae) from Guangxi Zhuang Autonomous Region, China.

Three species of the Neoperlamontivaga group are described from Guangxi Zhuang Autonomous Region of southern China, including two new species, N.falcatata sp. nov. and N.shangsiensis sp. nov., and a new record for Guangxi: N.bilineata Wu & Claassen, 1934. Illustrations and color images are provided for the three species mentioned above, and the new species is compared with related congeners in the group. Notes on the distribution of the Neoperla species known from Guangxi are also given.

Effects of stream permanence on stonefly (Insecta, Plecoptera) community structure at Mammoth Cave National Park, Kentucky, USA.

Stoneflies (Plecoptera) are often associated with inhabiting cold perennial streams, but many species also inhabit intermittent streams that experience reduced or lack of flow during summer and autumn. In this study, the influence of stream permanence on stonefly assemblage composition and spatial distribution at Mammoth Cave National Park, Kentucky, USA, was addressed, based on a 14 month sampling regime from the fullest range of stream sizes and habitable flow regions available. Adult stoneflies were collected monthly from 43 sites at the Park plus an additional two sites at the near-adjacent Western Kentucky University Green River Preserve. Collections were done from December 2018-November 2019 using a standard timed protocol with beating sheets for adults and once in December 2019-January 2020 for larvae. Stream sites were assigned one of five category types: perennial spring runs, perennial spring seeps, upland perennial streams, perennial riverine and summer dry runs. In total, 34 species were collected. The most prominent difference in stonefly community structure was between spring runs, spring seeps and summer dry streams vs. upland perennial streams. Approximately 88% of species collected had univoltine-fast life cycles and 79% likely had an extended period of egg or larval diapause. Due to the predominance of small upland perennial and summer dry streams, species commonly typically found in larger lotic systems are fundamentally filtered out of the region due to the lack of available habitats. Species able to survive in intermittent habitats do so by life history adaptations including to survive desiccation as larvae or eggs.

Vulnerability of Aquatic Insect Species to Insecticides, Depending on Their Flight Period and Adult Life Span.

Effects of insecticides on terrestrial adult life stages of otherwise aquatic insects, such as mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), are largely unknown. In the present study, a risk model was used to pinpoint the species most likely to experience effects due to spray drift exposure during the adult life stage. Using data from an earlier case study with lambda-cyhalothrin, 6 species with different life cycle traits were used to explore how life cycle characteristics may influence vulnerability. In addition, we performed a generic calculation of the potential effect on the terrestrial life stages of 53 species (including 47 species with unknown sensitivity). Our approach incorporated temporal and spatial distribution of both the insect and the insecticide, creating different exposure conditions among species due to variation in the relative proportion of the populations present at the time of insecticide spraying. The Ephemeroptera species represented were least vulnerable due to their extremely short adult life span and relatively short flight period. Based on their life cycle characteristics, Plecoptera and Trichoptera species were more vulnerable. These vulnerable species segregated into 2 distinct groups; one with a long adult life span to emergent period ratio and another with a high overlap between emergent period and spraying season. We therefore recommend that future ecotoxicological tests be done on species with these life cycle characteristics. Environ Toxicol Chem 2021;40:1778-1787. © 2021 SETAC.

The genus Anacroneuria Klapálek, 1909 (Plecoptera: Perlidae) from Maranhão State, northeastern Brazil.

Based on collections made from streams of the Itapecuru, Parnaíba and Tocantins River basins, three species of Anacroneuria Klapálek are recorded for the first time from Maranhão State, northeastern Brazil: A. atrifrons Klapálek, A. minuta Klapálek and A. singularis Righi-Cavallaro Lecci. Additionally, A. leccii sp. nov. is described from this material and remarks concerning A. marlieri are also presented.

Trichoptera and Plecoptera of the Seybouse River, northeast Algeria: Distribution, phenology and new records.

The stoneflies and caddisflies of North Africa are still poorly known as vast areas of Algeria have yet to be investigated. A survey of the macroinvertebrates of the Seybouse River, northeast Algeria, was carried out from July 2014 to December 2016. Three species of stoneflies (Capnopsis schilleri, Capnioneura petitpierreae, and Tyrrhenoleuctra tangerina) and five taxa of caddisflies (Mesophylax aspersus, Hydropsyche maroccana, H. resmineda, H. artax/lobata, and H. gr. pellucidula) were identified. All taxa are new records to the Seybouse River and seven of them are new to northeastern Algeria. A multivariate analysis indicated that the Hydropsychidae exhibited a clear longitudinal gradient along the Seybouse River while Mesophylax aspersus seemed adapted to species-poor, intermittent streams. Further investigations of the stoneflies and caddisflies may inform conservation efforts and will prove useful to monitor the Seybouse River and similarly threatened North African rivers and streams.