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Smoky rubyspot damselflies (Hetaerina titia Drury, 1773) are one of the most commonly encountered odonates along streams and rivers on both slopes of Central America and the Atlantic drainages in the United States and southern Canada. Owing to their highly variable wing pigmentation, they have become a model system for studying sexual selection and interspecific behavioral interference. Here, we sequence and assemble the genome of a female smoky rubyspot. Of the primary assembly (i.e. the principle pseudohaplotype), 98.8% is made up of 12 chromosomal pseudomolecules (2N = 22A + X). There are 75 scaffolds in total, an N50 of 120 Mb, a contig-N50 of 0.64 Mb, and a high arthropod BUSCO score [C: 97.6% (S: 97.3%, D: 0.3%), F: 0.8%, M: 1.6%]. We then compare our assembly to that of the blue-tailed damselfly genome (Ischnura elegans), the most complete damselfly assembly to date, and a recently published assembly for an American rubyspot damselfly (Hetaerina americana). Collectively, these resources make Hetaerina a genome-enabled genus for further studies of the ecological and evolutionary forces shaping biological diversity.

Genetic diversity and ecology are two important aspects of vector species crucial to a full understanding of disease epidemiology. In this study, we examined genetic diversity, genetic structure and the physiochemical parameters of the breeding habitats of the two significant black fly vector species, Simulium chumpornense Takaoka and Kuvangkadilok and S. nodosum Puri, from Laos. Genetic diversity of S. chumpornense in Laos was relatively high with maximum genetic divergence of 3.05% but no significant genetic differentiation between populations. Comparisons with conspecific populations from Thailand also found no genetic differentiation between the two countries. This possibly related to the recent history of this species, as a very recent (31,000 years ago) historical population expansion was detected. Physicochemical parameters of the breeding habitats suggest the ability to utilize diverse stream sizes from small flows (1 m wide) to huge rivers (290 m or more wide). Populations of S. nodosum from Laos had low genetic diversity with maximum genetic divergence of 2.56% and no genetic structuring among populations. Comparisons with those reported from other countries revealed five genetically divergent lineages (I–V) with minimum genetic divergence of 1.36%. The majority (42 of 52) of specimens from Laos belonged to lineage I and the remaining (10) comprised lineage II. Lineage I is the largest and representative of specimens from Thailand, Myanmar, Vietnam, Taiwan and Laos. Population history analysis revealed that lineage I had undergone recent demographic expansion dating back to 7000 years ago. This very recent population expansion resembles others reported from Thailand and possibly indicates a response to increasing human and domestic animals following the agricultural revolution. Breeding sites of S. nodosum are diverse in respect to elevation, velocity, water conductivity and streambed particle size. The ability to utilize a wide variety of breeding sites could promote the production of a large adult population, which can be a pest for humans and other animals. [ABSTRACT FROM AUTHOR]

Recent decades have witnessed substantial changes in freshwater biodiversity worldwide. Although research has shown that freshwater biodiversity can be shaped by changes in habitat diversity and human‐induced pressure, the potentials for interaction between these drivers and freshwater biodiversity at large spatial extents remain unclear. To address these issues, we employed a spatially extensive multitrophic fish and insect database from 3323 stream sites across the United States, to investigate the ability of habitat diversity to modulate the effect of human pressure on the richness and abundance of fish and insects. We found evidence that high levels of habitat diversity were associated with increased richness and abundance of fish and insects (including whole‐assemblage and individual trophic guilds). We also show that the effects of human pressure on the richness and abundance of fish and insects tend to become positive at high levels of habitat diversity. Where habitat diversity is low, human pressure strongly reduces insect richness and abundance, whereas these reductions are attenuated at high levels of habitat diversity. Structural equation modeling revealed that human pressure reduced habitat diversity, indirectly negatively affecting the richness and abundance of fish and insects. These findings illustrate that, in addition to promoting greater fish and insect biodiversity, habitat diversity may mitigate the deleterious effects of human pressures on these two stream assemblages. Overall, our study suggests that maintaining high levels of habitat diversity is a useful way to protect freshwater biodiversity from ongoing increases in human pressure. However, if human pressures continue to increase, this will reduce habitat diversity, further threatening stream assemblages. [ABSTRACT FROM AUTHOR]

This research delves into the effects of weir‐induced habitat fragmentation on the diversity and structure of benthic macroinvertebrate communities in Topyeong Stream in the Republic of Korea. Through comprehensive zonation, environmental assessments and analyses of macroinvertebrate populations, the study brings to light the significant impact of physical barriers within aquatic ecosystems. Findings reveal notable differences in macroinvertebrate diversity among various stream zones, with alpha diversity measurements demonstrating the significant influence of habitat conditions on biodiversity. Beta diversity analyses uncovered considerable species turnover, pointing to distinct ecological features within fragmented habitats. Mantel tests solidified a significant link between geographical separation and species composition, highlighting the critical impact of spatial isolation arising from habitat fragmentation. The research also pinpointed environmental factors, including habitat size and depth variation, as critical influences on macroinvertebrate community dynamics. Discussions on conservation tactics centered on habitat restoration and forward‐thinking water management strategies aim to counteract the negative consequences of fragmentation and drought. This study emphasizes the essential need for cohesive conservation initiatives to preserve aquatic biodiversity and the functionality of ecosystems amidst human‐induced challenges. [ABSTRACT FROM AUTHOR]

Ephemeroptera nymphs are globally recognized for their sensitivity to decreased oxygen levels in aquatic habitats, leading to their frequent use as biological indicators in various monitoring projects worldwide. However, studies utilizing Ephemeroptera in Indonesia have remained largely unknown. This study aims to document the use of Ephemeroptera as bioindicators for assessing surface water quality status in Indonesia. This includes understanding their distribution and the types of surface water habitats that have been investigated using this order as an indicator. There are 47 published papers utilizing Ephemeroptera as a bioindicator for assessing surface water health in Indonesia which were gathered through Google Scholar. Bioindicator studies utilizing Ephemeroptera in Indonesia have only emerged in the last decade. Currently, research on Ephemeroptera as bioindicators for surface waters has predominantly focused on Java Island. Regions on other islands remain relatively understudied, particularly in eastern Indonesia. River habitats lead in the number of observed habitat types. With this knowledge, future research on utilizing Ephemeroptera as bioindicators should prioritize areas beyond Java Island and focus on habitat types that have been less explored, including irrigation canals, paddy fields, waterfalls, wetlands, and springs. [ABSTRACT FROM AUTHOR]

Gerromorpha Popov, 1971 is a fascinating and diverse insect lineage that evolved about 200 Mya to spend their entire life cycle on the air–water interface and have since colonized all types of aquatic habitats. The subfamily Halobatinae Bianchi, 1896 is particularly interesting because some species have adapted to life on the open ocean—a habitat where insects are very rarely found. Several attempts have been made to reconstruct the phylogenetic hypotheses of this subfamily, but the use of a few partial gene sequences recovered only a handful of well-supported relationships, thus limiting evolutionary inferences. Fortunately, the emergence of high-throughput sequencing technologies has enabled the recovery of more genetic markers for phylogenetic inference. We applied genome skimming to obtain mitochondrial and nuclear genes from low-coverage whole-genome sequencing of 85 specimens for reconstructing a well-supported phylogeny, with particular emphasis on Halobatinae. Our study confirmed that Metrocorini Matsuda, 1960, is paraphyletic, whereas Esakia Lundblad, 1933, and Ventidius Distant, 1910, are more closely related to Halobatini Bianchi, 1896, than Metrocoris Mayr, 1865, and Eurymetra Esaki, 1926. We also found that Ventidius is paraphyletic and in need of a taxonomic revision. Ancestral state reconstruction suggests that Halobatinae evolved progressively from limnic to coastal habitats, eventually attaining a marine lifestyle, especially in the genus Halobates Eschscholtz, 1822, where the oceanic lifestyle evolved thrice. Our results demonstrate that genome skimming is a powerful and straightforward approach to recover genetic loci for robust phylogenetic analysis in non-model insects. [ABSTRACT FROM AUTHOR]

The creation of wetlands along river channels, or inter-levee floodplain wetlands (ILWs), increases the cross-sectional area of rivers for flood control and is an effective nature-based solution (NbS) that is expected to achieve both flood control and biodiversity conservation in floodplains in riverine areas in Japan. To clarify the differences in habitat functions between ILWs and rice paddy fields, we surveyed the species assemblage and habitat usage of aquatic animal assemblages in ILWs and nearby rice paddies in the Nobi Plain of central Japan. Rana japonica bred in the ILWs, and taxon numbers of Odonata larvae and aquatic Hemiptera were greater in ILWs than in rice paddies. Fish taxa were also more abundant in the ILWs. ILWs were characterized mainly by taxa with a preference for permanent water bodies in their life history, whereas Dryophytes japonicus, Pelophylax porosus brevipodus, and Fejervarya kawamurai inhabited and bred mainly in the rice paddies, and the number of taxa of aquatic Coleoptera was also higher. The assemblages in the rice paddies were characterized by pioneer taxa with a preference for temporary waters as their primary breeding sites. Our results show that the creation of ILWs for flood control and the maintenance of rice paddies could help to conserve the original floodplain biodiversity through the complementarity of these different wetland types.

Damselflies and dragonflies (Order: Odonata) play important roles in both aquatic and terrestrial food webs and can serve as sentinels of ecosystem health and predictors of population trends in other taxa. The habitat requirements and limited dispersal of lotic damselflies make them especially sensitive to habitat loss and fragmentation. As such, landscape genomic studies of these taxa can help focus conservation efforts on watersheds with high levels of genetic diversity, local adaptation, and even cryptic endemism. Here, as part of the California Conservation Genomics Project (CCGP), we report the first reference genome for the American rubyspot damselfly, Hetaerina americana, a species associated with springs, streams and rivers throughout California. Following the CCGP assembly pipeline, we produced two de novo genome assemblies. The primary assembly includes 1,630,044,487 base pairs, with a contig N50 of 5.4 Mb, a scaffold N50 of 86.2 Mb, and a BUSCO completeness score of 97.6%. This is the seventh Odonata genome to be made publicly available and the first for the subfamily Hetaerininae. This reference genome fills an important phylogenetic gap in our understanding of Odonata genome evolution, and provides a genomic resource for a host of interesting ecological, evolutionary, and conservation questions for which the rubyspot damselfly genus Hetaerina is an important model system.

Tests for the role of species' relative dispersal abilities in ecological and biogeographical models rely heavily on dispersal proxies, which are seldom substantiated by empirical measures of actual dispersal. This is exemplified by tests of dispersal–range size relationships and by metacommunity research that often features invertebrates, particularly freshwater insects. Using rare and unique empirical data on dispersal abilities of caddisflies, we tested whether actual dispersal abilities were associated with commonly used dispersal proxies (metrics of wing size and shape; expert opinion). Across 59 species in 12 families, wing morphology was not associated with actual dispersal. Within some families, individual wing metrics captured some dispersal differences among species, although useful metrics varied among families and predictive power was typically low. Dispersal abilities assigned by experts were either no better than random or actually poorer than random. Our results cast considerable doubt on research underpinned by dispersal proxies and scrutiny of previous research results may be warranted. Greater progress may lie in employing innovative survey and experimental design to measure actual dispersal in the field. [ABSTRACT FROM AUTHOR]

Simple Summary: Water colour is an important physicochemical property of water that affects aquatic communities. Land-use change has led to water colour darkening in lotic habitats, such as streams and rivers. Here, I evaluate whether urban land-use change affects water colour in urban ponds, a type of lentic habitats, and how diving beetles (Dytiscidae) respond to the water colour gradient in the Helsinki Metropolitan Area, Finland. The results show that urbanisation may not drive water darkening in urban ponds, possibly because urban ponds are often not connected to stormwater pipes. Diving beetles responded to the increasing pond water colour differently in the presence or absence of fish. Diving beetle species richness and abundance significantly increased along the water colour gradient in ponds with fish, but not in ponds without fish. Some species, such as the great diving beetle (Dytiscus marginalis), appear tolerant to brown water, whereas some species, such as the cherrystone beetle (Hyphydrus ovatus), prefer clear water. This study highlights that not all species benefit from increasing water colour. It is important to provide ponds with a gradient of water colour from clear to brown water in the landscape to meet the habitat requirements of different species for urban biodiversity conservation. Dramatic land-use changes in urban landscapes can drive water colour darkening by washing compounds, such as organic matter and iron, from terrestrial ecosystems into urban blue space, consequentially affecting aquatic communities. Here, I studied how pond water colour changes along an urban gradient and how diving beetles (Dytiscidae) respond to the water colour gradient in 11 ponds with fish and 15 ponds without fish in the Helsinki Metropolitan Area, Finland. I found that the pond water colour exhibited a non-significant decreasing pattern along the urban gradient, indicating that urbanisation may not necessarily drive brownification in urban ponds. Dytiscid species richness and abundance exhibited significant positive correlations with increasing water colour in ponds with fish but no significant correlation in ponds without fish. Some species, such as Agabus spp. and Dytiscus spp., appeared tolerant to highly coloured water, whereas some species, such as Hyphydrus ovatus and Hygrotus spp., tended to occur in clear water, indicating that brown water may provide dytiscids with prey refuges, but some species are intolerant to brown water. The study highlights the importance of urban pondscape heterogeneity to meet the needs of aquatic invertebrates that prefer different water colours and for the multifunctioning of urban ponds. [ABSTRACT FROM AUTHOR]

Biomonitoring with bioindicators such as river macroinvertebrates is fundamental for assessing the status of freshwater ecosystems. In Japan, water quality and biomonitoring surveys are conducted separately, leading to a lack of nationwide information on their relationships and the biological status of water quality monitoring (WQM) sites. To understand the biological status of WQM sites across Japan, we developed a multiple linear regression model to estimate the average score per taxon (ASPT) using river macroinvertebrate data surveyed at a total of 237 "aligned" sites based on the co-occurrence of biomonitoring and WQM sites. The resulting regression model with eight predictors, such as biological oxygen demand, the proportion of urban areas in the catchment, could predict ASPT with reasonable accuracy (e.g., an error of ±1 for 96% of the aligned data). Using this model, we estimated ASPT values at 2925 WQM sites in rivers nationwide, categorizing them into four levels of river environment quality: "very good" (29% of WQM sites), "good" (50%), "fairly good" (14%), and "not good" (8%). Furthermore, we observed statistically significant correlations (p < 0.05; 0.4 ≤ r ≤ 0.7) between ASPT and all eight macroinvertebrate metrics examined, such as mayfly and stonefly richness, providing ecological implications of changes in ASPT. [ABSTRACT FROM AUTHOR]

Genetic diversity and ecology are two important aspects of vector species crucial to a full understanding of disease epidemiology. In this study, we examined genetic diversity, genetic structure and the physiochemical parameters of the breeding habitats of the two significant black fly vector species, Simulium chumpornense Takaoka and Kuvangkadilok and S. nodosum Puri, from Laos. Genetic diversity of S. chumpornense in Laos was relatively high with maximum genetic divergence of 3.05% but no significant genetic differentiation between populations. Comparisons with conspecific populations from Thailand also found no genetic differentiation between the two countries. This possibly related to the recent history of this species, as a very recent (31,000 years ago) historical population expansion was detected. Physicochemical parameters of the breeding habitats suggest the ability to utilize diverse stream sizes from small flows (1 m wide) to huge rivers (290 m or more wide). Populations of S. nodosum from Laos had low genetic diversity with maximum genetic divergence of 2.56% and no genetic structuring among populations. Comparisons with those reported from other countries revealed five genetically divergent lineages (I–V) with minimum genetic divergence of 1.36%. The majority (42 of 52) of specimens from Laos belonged to lineage I and the remaining (10) comprised lineage II. Lineage I is the largest and representative of specimens from Thailand, Myanmar, Vietnam, Taiwan and Laos. Population history analysis revealed that lineage I had undergone recent demographic expansion dating back to 7000 years ago. This very recent population expansion resembles others reported from Thailand and possibly indicates a response to increasing human and domestic animals following the agricultural revolution. Breeding sites of S. nodosum are diverse in respect to elevation, velocity, water conductivity and streambed particle size. The ability to utilize a wide variety of breeding sites could promote the production of a large adult population, which can be a pest for humans and other animals.

A list of species of Lepidoptera, aquatic insects, and higher plant species inhabiting 22 National parks in Korea was compiled. A similarity analysis was performed to compare all National parks, and cladograms were constructed. In the case of higher plants, those inhabiting the Hallasan region were categorized as a separate group, while the plants living in National parks located near the southern and western coasts formed one group, and other terrestrial National parks were divided into two groups as follows: the Taebaek Mountain range/adjacent mountain group and the others group. Species of Lepidoptera, which appear to be related to plants, in the Hallasan, Taebaeksan, Taeanhaean, and Bukhansan mountains were each classified independently, and those in the Hallyeohaesang, Dadohaehaesang, Naejangsan, and Byeonsanbando in the southern and western parts of Korea were classified as a single group. In case of aquatic insects, those in the Hallasan, Taeanhaean, and Bukhansan region were categorized in independent groups, and other terrestrial National parks were placed in one group with high similarity. A similarity analysis was performed through a detailed classification of the habitats in National parks revealed that marine‐coastal National parks particularly showed low similarity with other mountainous National parks. In addition, other terrestrial National parks were further grouped into large and small National parks. Comparing the subject map that divided Korea into climate, vegetation, and topography, some marine‐coastal National park areas were confirmed to be distinguished from other areas. Furthermore, similarity analysis revealed that Gangwon‐do and Baekdu‐Daegan regions in Gyeongsangbuk‐do were categorized into one group with high similarity. [ABSTRACT FROM AUTHOR]

1. Integral to many ecological models is the notion that dispersal connects populations and communities in disparate locations. For stream insects, however, there is very little empirical information about which species and what proportion of the species in a community are likely to disperse, in what direction and how far they travel, and whether dispersal is successful in connecting populations and communities. This study examines whether species of caddisfly can disperse between catchments and potentially connect communities. 2. We used a novel sampling design comprising five pairs of streams. Each stream in a pair flowed from the same boundary, but in opposite directions and into isolated catchments. We surveyed abundances of adult caddisflies on the catchment boundary (boundary species) where there was no water (Up location), and on two locations per stream (Middle, Down locations) where there was permanently flowing water (resident species). If caddisflies fly along the topographic features of stream valleys, then we expected to find adults on the ridge between catchments and, if dispersal is successful, stream communities in adjacent catchments should have similar species composition. 3. Over 130 species of caddisfly (from 18 families) were collected. Approximately half of them occurred on at least one catchment boundary, and Up locations averaged almost 20 species. Boundary species included both the smallest‐ and largest‐bodied taxa and they were a near perfect subset of species in resident assemblages. However, boundary species were not simply the most common in resident assemblages. There was no evidence of sex‐biased dispersal. Unsurprisingly, assemblage composition varied across the landscape, within and among catchments. However, resident assemblages within stream pairs were significantly more similar to one another than unpaired streams in either the same or in different catchments. 4. Our results suggest that a surprisingly diverse set of caddisflies disperse up to catchment boundaries and potentially connect streams on either side of catchment divides. Nevertheless, many other caddisfly species were never recorded at Up sites and hence may never or only rarely reach catchment boundaries. 5. These outcomes suggest, firstly, that some caddisflies are capable of trans‐catchment dispersal but it is incorrect to assume that all caddisflies are good dispersers, as is often stated in the literature. Secondly, caddisfly assemblages in headwater streams may be less isolated than is often considered and the dendritic structure of stream networks may be less important for their distribution patterns than the proximity of tributaries in neighbouring catchments, in many landscapes. Trans‐catchment dispersal could ensure community connectivity and facilitate recovery after catchment‐wide extinctions. [ABSTRACT FROM AUTHOR]

Aquatic insects are found abundantly and exhibits high diversity in fresh water aquatic ecosystems. They serve as food item for the vertebrate and invertebrate predators and thus play a significant role in aquatic ecosystem. Insects responded well to a wide range of environmental disturbances and thus often are employed as proxies for water quality. The present study was carried out at Tamasi Lake, situated in Bhadravati Taluka of Chandrapur district, Maharashtra which comes under Tribal area. The year round investigation was carried out to evaluate the diversity of aquatic insects for a period of one year from June 2022 to May 2023. The present investigation shows the presence of total 28 species of aquatic insects from 5 orders and 18 families. The rich and varied diversity of aquatic insects indicate the moderate environmental condition of freshwater ecosystem under study and functioning properly. [ABSTRACT FROM AUTHOR]

Aquatic insects are found abundantly and exhibits high diversity in fresh water aquatic ecosystems. They serve as food item for the vertebrate and invertebrate predators and thus play a significant role in aquatic ecosystem. Insects responded well to a wide range of environmental disturbances and thus often are employed as proxies for water quality. The present study was carried out at Tamasi Lake, situated in Bhadravati Taluka of Chandrapur district, Maharashtra which comes under Tribal area. The year round investigation was carried out to evaluate the diversity of aquatic insects for a period of one year from June 2022 to May 2023. The present investigation shows the presence of total 28 species of aquatic insects from 5 orders and 18 families. The rich and varied diversity of aquatic insects indicate the moderate environmental condition of freshwater ecosystem under study and functioning properly.

Urban freshwater ecosystems often involve the introduction of predator species that affect biodiversity via both direct and indirect effects of predation, altering the distribution of prey species. Yet, limited research has explored indirect effects on aquatic invertebrates in urban pondscapes. Here, we use Dytiscidae as our study taxon to investigate how predator-prey interaction modifies the habitat use and habitat selection of macroinvertebrates in ponds of an urban landscape. We sampled dytiscids in 11 ponds with, and 15 ponds without fish, in Helsinki, Finland, during 2018 – 2020, and emergent plant cover in pond margins as a proxy for the quantity of prey refuges. We found (i) at the pond scale, vegetation cover can mitigate the negative effects of predators on dytiscid species richness and abundance, and dytiscids prefer microhabitats with bulrush and sedges to microhabitats with no vegetation or common reeds, reflecting the importance of providing aquatic plants with high structural complexity as prey refuges. (ii) At the landscape scale, small-sized dytiscids favour fishless habitats, and the community-weighted mean body size of dytiscids has seasonal fluctuations, with smaller body sizes in May and June than in July in fishless ponds, indicating that dytiscids select habitats to regulate their investment in vigilance according to their life cycles. Our findings highlight that predation can alter the habitat use and habitat selection of aquatic invertebrates. Mitigating predation risk at both the habitat scale and the landscape scale is crucial to facilitate the fitness of aquatic invertebrates, especially small-sized species, to promote their diversity in urban pondscapes.

The giant water bug Kirkaldyia deyrolli is one of the most well‐known endangered aquatic insects in Japan. The population of this species in Kyushu, one of the four major islands of the Japanese Archipelago, is extremely limited. In the present study, we identified a new population of K. deyrolli and undertook population genetic structure analyses based on genome‐wide nuclear DNA single nucleotide polymorphisms (SNPs). We collected samples using a nonlethal sampling method and obtained 59,279 SNPs. The results of our study confirm that sufficient SNP data for population genetic structure analysis can be obtained through nonlethal sampling. We determined that the newly identified population is genetically differentiated from a previously identified population on Kyushu. Therefore, this population is considered highly important for the conservation of K. deyrolli in Kyushu. [ABSTRACT FROM AUTHOR]

Dramatic land-use changes in urban landscapes can drive water colour darkening by washing compounds, such as organic matter and iron, from terrestrial ecosystems into urban blue space, consequentially affecting aquatic communities. Here, I studied how pond water colour changes along an urban gradient and how diving beetles (Dytiscidae) respond to the water colour gradient in 11 ponds with fish and 15 ponds without fish in the Helsinki Metropolitan Area, Finland. I found that the pond water colour exhibited a non-significant decreasing pattern along the urban gradient, indicating that urbanisation may not necessarily drive brownification in urban ponds. Dytiscid species richness and abundance exhibited significant positive correlations with increasing water colour in ponds with fish but no significant correlation in ponds without fish. Some species, such as Agabus spp. and Dytiscus spp., appeared tolerant to highly coloured water, whereas some species, such as Hyphydrus ovatus and Hygrotus spp., tended to occur in clear water, indicating that brown water may provide dytiscids with prey refuges, but some species are intolerant to brown water. The study highlights the importance of urban pondscape heterogeneity to meet the needs of aquatic invertebrates that prefer different water colours and for the multifunctioning of urban ponds.

Harpellales (Zoopagomycotina) is a fungal order of which species inhabit the intestine of aquatic arthropods by attaching their thalli to the host’s gut lining. Harpellales consists of 270 species with over half found in Chironomidae larvae. The aim of this research is to document a species, S. pedifer, new to Japan with a chironomid host association and to list all Chironomidae-commensal species of Harpellales with host and country information.

ABSTRACT Two recently revealed genera, Claudiotendipes, consisting of three distinct species, and the monotypic Tapajos, have new species described. We describe and figure Claudiotendipes gilbertoi sp. n., based on male adult specimens collected in the southern Atlantic Forest of Rio Grande do Sul State. Additionally, we describe and figure Tapajos froehlichi sp. n., from male adults collected in the Amazon Forest from Amazonas and Rondônia States. In order to place the newly described T. froehlichi sp. n., minor emendations have been made to the diagnosis and description of Tapajos.

Resource flows between freshwater ecosystems can greatly affect foodweb dynamics. The seasonal movement of a family of aquatic insects, water boatmen, or corixids (Hemiptera: Corixidae) represents an important transfer of resources between wetland and river ecosystems. Corixids migrate en masse from wetlands in the North American prairies to rivers every autumn to overwinter. In the North and South Saskatchewan rivers, Saskatchewan, Canada, several fish species prey upon these migratory corixids. Here, we examined the utility of the stable isotope ratio of sulfur, δ34S, in tracing the migration of corixids between wetlands and the North and South Saskatchewan rivers. We also assessed the extent to which riverine fish use migratory corixids as a dietary subsidy. We found that both corixids and other wetland invertebrates exhibited a mean δ34S value of −10.5 ± 5.8‰, lower than riverine invertebrates at −4.1 ± 4.1‰. Specifically, riverine invertebrates from the South Saskatchewan River were more depleted in 34S than those from the North Saskatchewan River, with means of −5.1 ± 4.1‰ and −1.4 ± 2.8‰, respectively. In summer, corixid-feeing and noncorixid-feeding fish exhibited similar δ34S values in liver tissue, whereas in spring and autumn, corixid feeders exhibited more negative δ34S values. Isotope mixing models indicated that corixid-feeding species may have derived 34 to 65% of liver tissue from wetland sources in spring, 15 to 34% in summer, and 41 to 78% in autumn, whereas contributions to noncorixid-feeding species ranged from 4 to 17% across all seasons. We conclude that δ34S has the potential to trace insect movement and consumer use between isotopically distinct freshwater systems. [ABSTRACT FROM AUTHOR]

The egg stage in insect development is vulnerable to fluctuations in environmental conditions and attacks by natural enemies. Protective devices are effective means of avoiding both abiotic and biotic damage to eggs. Although some insects use their faeces as a protective device, few studies have focused on using faeces for egg protection, and studies that examined the mechanism are lacking. Females of a water scavenger beetle, Coelostoma stultum, typically lay eggs and coat them with cocoons and their faeces. The efficacy of a double defensive device, however, remains uncertain. Here, we conducted field observations and laboratory experiments to assess the protective effects of cocoons with faecal coating on eggs against predation and determine the duration and mechanisms of this defence. Our findings reveal that the faeces on the egg cocoon protected eggs from predation by the pill bugs, Armadillidium vulgare, and marsh slugs, Deroceras laeve. Laboratory experiments showed that the defensive effect of faecal coating was maintained for three days and decreased daily. The double protective traits with faecal coating on the egg cocoons protected the eggs from instense predation pressure in C. stultum. The behavioural patterns of the pill bugs and egg predation rates indicate that the faecal coating behaviour in C. stultum protects eggs with chemical compounds and textural camouflage in mud when the antennae of the pill bugs touch faeces. It is important to note that for this defence to be effective, the chemistry and texture of the faeces should be similar to that of the oviposition sites. [ABSTRACT FROM AUTHOR]

Potential adverse ecological effects of expanded uranium (U) mining within the Grand Canyon region motivated studies to better understand U exposure and risk to endemic species. This study documents U exposures and analyzes geochemical and biological factors affecting U bioaccumulation at spring-fed systems within the Grand Canyon region. The principal objective was to determine if aqueous U was broadly indicative of U accumulated by insect larvae, a dominate fauna. Analyses focused on three widely distributed taxa: Argia sp. (a predatory damselfly), Culicidae (suspension feeding mosquitos), and Limnephilus sp. (a detritivorous caddisfly). The study showed that U accumulated by aquatic insects (and periphyton) generally correlated positively with total dissolved U, although correlations were strongest when based on modeled concentrations of the U-dicarbonato complex, UO2(CO3)2–2, and UO2(OH)2. Sediment metal concentration was a redundant indicator of U bioaccumulation. Neither insect size or U in the gut content of Limnephilus sp. substantially affected correlations between aqueous U and whole-body U concentrations. However, in Limnephilus sp., the gut and its content contained large quantities of U. Estimates of the sediment burden in the gut indicated that sediment was a minor source of U mass but contributed substantially to the total insect weight. As a result, whole-body U concentration would tend to vary inversely with the sediment burden of the gut. The correlations between aqueous U and bioaccumulated U provide an initial relational baseline against which newly acquired data could be evaluated for changes in U exposure during and after mining operations. [ABSTRACT FROM AUTHOR]

Human activities may influence the diversity of aquatic insects in rivers. This study aims to assess the diversity of aquatic insects and their relation with mercury levels and water quality along rivers located near the gold mine in Poboya, Central Sulawesi. The insects were collected at six locations based on human activity levels. At each site, the mercury level of water was measured using atomic absorption spectrophotometry (AAS). In addition, water temperature, acidity, dissolved oxygen, and total dissolved solids were determined. The study recorded 23 species of aquatic insects belonging to 7 orders and 14 families. Mercury levels in the rivers did not exceed the threshold except at two sites and did not affect aquatic insects’ diversity. The diversity of aquatic insects, however, tends to decrease downstream. The diversity of aquatic insects, particularly the Ephemeroptera, Plecoptera, and Trichoptera orders, tended to be higher at the higher dissolved oxygen sites.

The males of the giant water bug, Kirkaldya deyrolli, care for egg masses on the emergent vegetation above the water surface in aquatic environments. A previous study reported that attending males supply the eggs with water and guard them against mature females (infanticide) until hatching. That study additionally concluded that males staying on the egg mass for longer than necessary may be a counterstrategy against females considering infanticide. In the present study, laboratory experiments were performed to evaluate the effect of conspecific females on paternal care during the egg-attending period using "with-" and "without-female" treatments. The hatching rates of eggs guarded by males with or without the presence of females were not significantly different. However, the proportion of males on the egg mass was significantly higher when the females were present than when not. We conclude that male behavior may be a counterstrategy against infanticidal females, in which males avoid and reduce the risk of detection by climbing out of the water when females are present. [ABSTRACT FROM AUTHOR]

Lake and stream fauna are frequently studied, yet surprisingly little is known about ecological and evolutionary dynamics of species that inhabit both lentic and lotic habitats. There are few examples of species co-occurring in different flow types, which raises questions about how co-occurrence may influence ability to adapt to changing climatic conditions. One such co-occurring species is the aquatic insect Limnephilus externus Hagen, 1861 (Trichoptera:Limnephilidae), a species known to be widely distributed in lakes of the Nearctic and Palearctic regions. Here, we test whether lake–stream populations of the caddisfly L. externus are evolutionarily or ecologically distinct. We examined larval body and case morphology, interspecies phoretic associations, and the mitochondrial DNA cytochrome c oxidase I gene among lake and stream populations of L. externus. We also explored potential morphological differences among distinct haplotypes. We observed differences between lake and stream populations in abundance, phenology, some aspects of body and case morphology, and abdominal mite presence, indicating that lakes and streams may yield distinct ecological phenotypes for this species. We also observed distinct regional differences in caddisfly body condition and case construction sturdiness and found distinct assemblages of microinvertebrates associated with the caddisfly's body and cases. Lake–stream L. externus did not show genetic divergence; however, 3 potentially distinct haplotypes were present across the research sites as well as in sequences from North America and Canada. Limnephilus externus appears to exhibit wide geographic range and low geographic sequence structure, which could account for the species' large variation in phenology and morphology at the lake–stream level. Combined life history and phylogenetic studies provide valuable insight into the ecological and evolutionary dynamics that influence the adaptability of aquatic fauna to climatic change. [ABSTRACT FROM AUTHOR]

Overwintering in shallow habitats presents a serious obstacle for aquatic invertebrates. Here we investigated the little-known ability of water boatmen (Hemiptera: Corixidae), an aquatic insect, to survive the winter encased in air pockets within the ice of shallow wetlands. We extracted and experimentally thawed large blocks of ice from prairie wetlands in Saskatchewan, Canada, from which we examined the species composition and revival of corixids. While multiple corixid species were present in wetlands prior to freeze-up, a single species, Cymatia americana Hussey, 1920, comprised the vast majority of corixids that were found within the ice later in winter. Only 4%–9% of corixids, all Cymatia americana, revived after ice thawing over both study years. Being encased within an air pocket appeared to be necessary for the survival of corixids in the ice, with up to 300 individuals grouped together. Other invertebrate taxa also revived after thawing, including Haliplidae and Dytiscidae (Coleoptera) encased within air pockets both alongside corixids and on their own, as well as Coenagrionidae (Odonata), Phryganeidae and Leptoceridae (Trichoptera), Chironomidae (Diptera), and Physidae and Planorbidae (Basommatophora), which appeared to be encased in solid ice. The ability to overwinter inside ice represents a little understood survival mechanism of aquatic invertebrates in shallow wetlands, which could confer energetic and reproductive advantages to those that endure until spring. [ABSTRACT FROM AUTHOR]

Floods affect the population structure of organisms that inhabit streams. In recent decades, the scale of floods has become larger due to climate change. Under these circumstances, on 12 October 2019, the largest typhoon in the history of observation in Japan struck the Japanese Archipelago. This typhoon caused heavy rainfall in various places, and the Chikuma–Shinano River System (Japan's largest) suffered great damage. Eight years before the large-scale disturbance in the river system, the population structure of the mayfly Isonychia japonica was studied in detail using quantitative sampling (population numbers and biomass) and by sequencing the mtDNA cytochrome c oxidase subunit I. To understand the impact of the flood on the population and genetic structures, we repeated the same research approximately 1 year after the flood. Direct comparison of sites before and after the flood revealed no significant changes between pre- and post-flood population genetic structure. This indicates high in situ resistance and/or resilience recovery of the populations to the disturbance. We hypothesize that this high resistance/resilience to flood disturbance is a result of strong selection for such traits in the rivers of the Japanese Archipelago, which are short, steep, flow rapidly and violently, and are strongly affected by floods. [ABSTRACT FROM AUTHOR]

We assessed the response of aquatic assemblages to 3 types of land uses (horticulture, forest, and rural/urban areas) and the relationship between physicochemical and environmental parameters of the Mae Ram River basin. The physicochemical and biological variables were significantly varied among the types of land uses. Diversity significantly declined in both horticultural and rural/urban areas. Traits were satisfactorily explained by environmental variables across land-use gradients. The main drivers of trait variations were divided into 2 groups: ammonia and nitrate at upstream horticultural sites and total dissolved solids, orthophosphate, and conductivity in downstream rural/urban areas which also influenced Caenidae distribution. Functional feeding groups (FFGs) did not conform completely to the river continuum concept. This could be related to the degradation of the basin resulting from human activities from upstream to downstream. Our results indicate that land-use type can help predict aquatic ecosystem health and anthropogenic support of a diverse community of aquatic insects in the Mae Ram River basin. [ABSTRACT FROM AUTHOR]

Vulnerability to warming is often assessed using short‐term metrics such as the critical thermal maximum (CTMAX), which represents an organism's ability to survive extreme heat. However, the long‐term effects of sub‐lethal warming are an essential link to fitness in the wild, and these effects are not adequately captured by metrics like CTMAX.The meltwater stonefly, Lednia tumana, is endemic to high‐elevation streams of Glacier National Park, MT, USA, and has long been considered acutely vulnerable to climate‐change‐associated stream warming. As a result, in 2019, it was listed as Threatened under the U.S. Endangered Species Act. This presumed vulnerability to warming was challenged by a recent study showing that nymphs can withstand short‐term exposure to temperatures as high as ~27°C. But whether they also tolerate exposure to chronic, long‐term warming remained unclear.By measuring fitness‐related traits at several ecologically relevant temperatures over several weeks, we show that L. tumana cannot complete its life‐cycle at temperatures only a few degrees above what some populations currently experience.The temperature at which growth rate was maximized appears to have a detrimental impact on other key traits (survival, emergence success and wing development), thus extending our understanding of L. tumana's vulnerability to climate change.Our results call into question the use of CTMAX as a sole metric of thermal sensitivity for a species, while highlighting the power and complexity of multi‐trait approaches to assessing vulnerability. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate protocols, in the United States, have been integral in the implementation of the Clean Water Act (33 U.S.C. §1251 et seq. (1972)). The methods in these protocols are designed to describe patterns of biological water quality and ecological condition relevant to legislative oversight, and require a tradeoff between taxonomic precision and protocol simplicity. The global similarity of ecological and evolutionary responses to the challenges of life in flowing waters, by stream organisms, has greatly facilitated the development and implementation of biological data from freshwater mussels, fishes and aquatic insects into streamlined regulatory frameworks. Unfortunately, the factors that expedite the use of benthic data into ecological descriptions sufficient for regulatory processes (taxonomic generalizations, standardization of sampling procedures to focus on a narrow subset of available habitats) also limit the utility of these methods in the conservation of benthic macroinvertebrate species (the large majority of which are insects). Using simple hypothetical simulations, some examples from a taxonomic and ecological database of one state in the USA (Illinois), and data from a large-scale inventory of aquatic insect species in a network of US National Parks, I illustrate how these methods are limited in their ability to effectively describe ecological patterns relevant to the conservation of aquatic insect species. I identify, challenge, and explore three basic assumptions implicit to the genus- and family-level identification methods widely used in freshwater benthic science, then discuss how the failure of these assumptions may create empirical, theoretical and philosophical obstacles to the interpretation of data and certainly hinder the conservation of species. I offer some hopeful suggestions for improving aquatic insect species conservation that are within the reach of all benthic freshwater ecologists.

The genus Aquarius, of the subfamily Gerrinae, was formerly divided into two species and one subspecies in Japan (A. paludum paludum, A. paludum amamiensis and A. elongatus, respectively). Aquarius haliplous Yasunaga et al. 2018 has recently been described as a new species, which occurs in brackish waters of Nagasaki Prefecture and is found sympatrically with the widely distributed species, A. p. paludum. However, they are considered to be speciated, with no cross‐breeding. In this study, molecular phylogenetic and morphological analyses were undertaken using the mitochondrial DNA COI (529 bp) and nuclear DNA histone H3 (314 bp) gene regions to investigate the genetic and morphological differentiation in the genus Aquarius, including A. haliplous, throughout Japan (including the islands). The results show that, unlike A. p. paludum, A. p. amamiensis and A. haliplous, A. elongatus displays substantial genetic differentiation. Considering that, although morphological differences exist in the antennae of A. p. paludum and A. p. amamiensis, A. haliplous has no clear genetic or morphological difference from A. p. paludum, and hence cannot be classified as a distinct species. Therefore, we propose that A. haliplous be synonymized with A. paludum. [ABSTRACT FROM AUTHOR]

Basic ecological information (e.g. habitat or distribution) is indispensable for conserving endangered species. The giant water bug Kirkaldyia deyrolli is an aquatic insect in the large stink bug family (Belostomatidae). It inhabits ponds and is a critically endangered species. In this study, we developed a species‐specific primer–probe set (the cytochrome c oxidase I region in mitochondrial DNA) that was used in real‐time polymerase chain reaction (PCR) assays to detect K. deyrolli environmental DNA (eDNA). Next, using eDNA analysis, we investigated the presence of K. deyrolli in 89 study ponds (including one pond that had already been identified as the habitat of this species) in Shimane Prefecture, Japan. The eDNA of K. deyrolli was detected in 11 of these 89 ponds. Furthermore, when the traditional method of direct capture survey was carried out in four of the 10 ponds where K. deyrolli eDNA had been detected and no prior occupancy information for this species was available, the capture of one K. deyrolli (female) was successful in only one pond. This study showed that combining eDNA analysis and direct capture methods can lead to discovering previously unknown habitats essential for conserving an endangered species. [ABSTRACT FROM AUTHOR]

Diel and seasonal changes in the gut contents of omnivorous–carnivorous macroinvertebrates were examined in a Japanese mountain stream based on direct observation of gut contents. Carnivorous–omnivorous (predator) macroinvertebrates were sampled at four time periods (02:00–03:00, 08:00–09:00, 14:00–15:00, and 20:00–21:00) on 3 days in each of March, June, September, and December. A total of 1391 individual macroinvertebrates belonging to 71 taxa were dissected: identifiable gut contents were observed in 928 individuals and prey identified to the family level were observed from the guts of 564 individuals. Using nonmetric multidimensional scaling, interspecific variation in foraging patterns was summarized into two axes that approximately correspond to body size and habitat preferences of prey taxa. Although seasonal patterns in the number of prey individuals in a gut varied among taxa, in March and December, several predators notably foraged on taxa such as Simuliidae, which inhabits stone surfaces in river sections with a rapid current. This pattern may be explained by season‐specific prey availability and predation risks from vertebrates. Diel changing patterns in the number of prey individuals per gut varied among predator taxa, and most predators did not show obvious proportional changes in gut contents. These results indicate that subcompartments of interaction networks and numerous indirect effects via intraguild predation potentially exist within the "guild" of macroinvertebrates, which are often summarized as mesopredators of stream food webs. [ABSTRACT FROM AUTHOR]

Dragonflies and damselflies (Order Odonata) are a group of aquatic insects that are important biotic components in an aquatic ecosystem. More than 250 species of Odonata are known to occur in Peninsular Malaysia. However, there is still no published record of Odonata from Batu Caves, Selangor. Hence, a series of field surveys were conducted from April to August 2019. A total of 25 species from four families were recorded, representing 10% of species known to Peninsular Malaysia. Of these, 19 species belong to the family Libellulidae, four species to family Coenagrionidae, and one species each from families Platycnemididae and Gomphidae. Notable records were the damselflies Ceriagrion auranticum and Ceriagrion chaoi, and the dragonfly Camacinia gigantea. Ceriagrion auranticum is a new record for the state of Selangor. Though its coverage area is small with limited aquatic habitats, Batu Caves still holds a substantial number of Odonata species. [ABSTRACT FROM AUTHOR]

Lethocerus patruelis (Stål, 1854) is the only member of the Belostomatidae family in Europe. During the last decades, records of this giant water bug have become frequent in south-eastern Italy, but with no evidence about its origin (man-mediated unintentional introduction or a natural westward spread). The status of this species in Italy is still uncertain, but the man-mediated unintentional introduction seems the most probable, even through multiple introductions. The first record of Lethocerus cf. patruelis for the Campania region (the first one on the Tyrrhenian side of Italy) is here reported, suggesting the already registered tendency of this species to expand, at least in Europe. Several topics need to be evaluated, in the light of its status in Italy and its management. [ABSTRACT FROM AUTHOR]

A new faunistic record and the description of a new species of Sisyra Burmeister, 1839 (Neuroptera: Sisyridae) are presented in this paper: Sisyra bureschi Rausch et Weißmair, 2007 is reported for the first time from Sweden, and Sisyra mononoke sp. nov. is described from India, Kashmir. Additionally, Sisyra flavicornis Comstock, 1918, a species described from India, is proposed to be removed from Sisyra. [ABSTRACT FROM AUTHOR]

The abundance of water strider Ptilomera dromas Breddin (Hemiptera: Gerridae) in Ciliwung River related to water quality. Water-strider Ptilomera dromas Breddin (Gerridae: Hemiptera) is an aquatic insect that is commonly found in various waters, such as rivers, ponds, and lakes. The purpose of this research was to study the abundance of P. dromas in Ciliwung river in relation to its water quality. The abundance of P. dromas was surveyed at five stations, i.e. Cilember, Cijulang, Gadog, Katulampa, and Sempur stations. Environmental parameters measured were water temperature, air temperature, pH, water flow, biological oxygen demand (BOD), dissolved oxygen (DO), free CO2 level, nitrogen total, water hardness, and total suspended solid (TSS). The relationship of P. dromas abundance with environment parameters was analyzed by using general linear model (GLM). Results showed that the highest abundance of P. dromas was found in Gadog station, followed by Cilember, Katulampa, and Cijulang stations. The population of P. dromas was not found in Sempur station, which might be related to the presence of Katulampa weir that acts as physical barrier and due to high BOD and TSS values. Based on GLM analysis, water hardness and pH were correlated positively with abundance of P. dromas. The existence of P. dromas in the upstream stations is linked to the high water quality and low pollution of waters.

Aquatic plants are important prey refuges for aquatic organisms, and their species richness is positively related with aquatic invertebrate species richness. Yet, it is unclear how the quantity of refuges, i.e. aquatic vegetation cover, affect aquatic invertebrate assemblages and their habitat use under different levels of predation risk (e.g. in the presence or absence of fish), nor at different scales (i.e. microhabitat and pond scales). Here, we investigated how provision of refuges affects diving beetle (Dytiscidae) species richness and abundance in the presence and absence of fish predators. We sampled diving beetles (Dytiscidae) with 1-L activity traps and estimated emergent plant cover at both the pond and microhabitat scales. We found that plant cover affected dytiscid populations differently: At the pond scale, dytiscid presence was positively correlated with increasing plant cover, both with and without fish, indicating the importance of emergent plants for aquatic biodiversity. At the microhabitat scale, dytiscid species richness and abundance were positively correlated with increasing plant cover in ponds with fish, but there was no such relationship in ponds without fish, emphasizing that the level of predation risk can alter prey species’ use of prey refuges. Our findings provide evidence that the availability of both vegetated and non-vegetated microhabitats can benefit aquatic invertebrates. We suggest maintaining variation in the provision of emergent plant cover, to retain high habitat heterogeneity in urban ponds and to enhance freshwater biodiversity.

Simple Summary: Food security concerns are growing due to the rapid increase in the world population. From this perspective, insects are a possible sustainable food source because of their nutritional value and the sustainability of their production system. Although the human consumption of edible insects has been a culturally long-standing practice, the nutritional literature on aquatic insects is not complete. Thus, the aims of the present study were to: (1) confirm the nutritional characteristics of odonate larvae (Libellulidae: Pantala sp.), including quantifying the bioaccumulation; and (2) investigate the microplastic accumulation in odonate larvae living in rice fields. The results show that odonates such as Pantala sp. are a good source of protein, minerals, essential amino acids, and long-chain polyunsaturated fatty acids. However, although the odonates seem to be a good source of nutrition, they may typically contain bioaccumulation, including microplastics, from their diets and habitats. Although the human consumption of aquatic insects is prevalent in many regions, the nutritional composition of the insects has not been comprehensively determined. The proximate composition of Pantala sp. was shown to be a good source of protein (49.45 ± 0.32 g/100 g DW), as well as of minerals such as sodium, calcium, potassium, phosphorus, zinc, and iron. All nine essential amino acids are present in this species, with valine being the most abundant. The major fatty acids are palmitic acid (1.19 ± 0.02 g/100 g DW), oleic acid (0.63 ± 0.02 g/100 g DW), and linoleic acid (0.55 ± 0.01 g/100 g DW). Lead (Pb), arsenic (As), and cadmium (Cd) showed a value of 0.18 ± 0.01 mg·kg−1, 3.51 ± 0.12 mg·kg−1, and 0.17 ± 0.00 mg·kg−1, respectively. Furthermore, microplastic (MP) contamination in odonate larvae (419 individuals belonging to three identified families) was found in varying shapes, e.g., fibers, fragments, and rods. FTIR analysis revealed the following MP polymers, polyethylene terephthalate, polyvinyl acetate, bis(2-ethylhexyl), polybutadiene, poly(methyl methacrylate-co-methacrylic acid); P(MMA-co-MA), poly(ethylene glycol) tetrahydrofurfuryl ether, poly(acrylonitrile-co-butadiene), and polypropylene glycol. The results of this work could be a nutritional reference for food security and the risk of eating insects. [ABSTRACT FROM AUTHOR]

Cross-boundary movements of organisms can act as important ecosystem linkages by subsidizing food webs. We investigated the magnitude and implications of a little understood food web subsidy in the form of migrating aquatic insects, corixids (Hemiptera: Corixidae), that fly from geographically isolated wetlands into large rivers in the Prairie Pothole Region (PPR) of North America every fall, to overwinter. We found that these migrations can lead to drastically increased riverine corixid densities as high as ~ 3,000 individuals/m2 within areas of standing or slow-moving water, with ~ 500 g of corixid material entering every meter of water immediately adjacent to the banks of rivers, where landings are concentrated. This movement shifts the species assemblage in rivers to one dominated by wetland-breeding species, namely Callicorixa audeni, Sigara bicoloripennis, and Sigara decoratella. Stomach content analyses of fish reveal that goldeye (Hiodon alosoides), mooneye (Hiodon tergisus), longnose sucker (Catostomus catostomus), and white sucker (Catostomus commersoni) make heavy use of this forage subsidy, with corixids occurring in 97% to 100% of these fishes and accounting for 38% to 97% of stomach contents by weight during the corixid migration period in fall. We estimate that seasonal migrations could result in ~ 1500 metric tons of corixids entering the North and South Saskatchewan rivers within Saskatchewan, and ~ 12,000 tons of biomass moving between wetlands and rivers across the entire PPR. Our study has demonstrated an extensive cross-boundary flux that occurs between spatially separated wetland and river ecosystems, highlighting a need for conservation to ensure that this connection is maintained. [ABSTRACT FROM AUTHOR]

The invasive floating aquatic macrophyte giant salvinia (Salvinia molesta) can rapidly alter ecosystem stability by forming a thick vegetative mat on the water surface. Management efforts are often required to clear waterways, and field releases of the salvinia weevil (Cyrtobagous salviniae) has been successful in restoring aquatic systems. Measuring weevil densities is critical to determine the success of this agent, thus routine Berlese funnel extractions from salvinia should be conducted. A laboratory study was designed to examine how to optimise adult weevil extraction under realistic salvinia biomasses and light intensities (heat source), and a second lab study was conducted to determine the effect of temperature and relative humidity on adult weevil behaviour. The objectives were to improve recommendations to ensure accurate population estimates in a reasonable period and understand what may drive adult weevil movement. We found that weevil movement from salvinia was initiated by increasing temperature above 40°C and decreasing relative humidity below 40%. For the purpose of expediting management decisions, we suggest completing extractions between 48 and 72 h, which requires biomass to be between 0.3 and 0.6 kg with halogen light bulbs of 60 or 75 watts. Additionally, we discovered that thermal stress to the insect was buffered by relative humidity, with individuals showing signs of stress at 3.5°C less when subjected to low initial humidity (∼55%), relative to high (100%). The change in thermal tolerance under different humidity scenarios may be explained by the weevil being a semi-aquatic insect that requires an aquatic plant host. [ABSTRACT FROM AUTHOR]

Creeping water bugs (Naucoridae) are predatory aquatic insects widely distributed in the Neotropical region. This study describes the structure of the male reproductive tract in two species, Limnocoris porphyros Nieser & Lopez Ruf, 2001 (Limnocorinae) and Pelocoris subflavus Montandon, 1898 (Naucorinae), under light microscopy. Both in L. porphyros and P. subflavus, the reproductive tract of sexually mature males consists of a pair of testes, efferent ducts, deferent ducts, seminal vesicles, two pairs of accessory glands, and an ejaculatory duct. Each testis has seven follicles. Deferent ducts were long with a dilation forming the seminal vesicle. Post‐vesicular deferent ducts were long, coiled, and contained spermatozoa. Characters derived from anatomy and histology of the male reproductive tract in the two species, expand the knowledge on reproductive biology and provide new data that can enhance behavioural research and contribute to understand the evolutionary history of aquatic Heteroptera. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in freshwater ecosystems is a serious threat to aquatic organisms. Species of Megaloptera are important predators of aquatic invertebrates and have been widely used as bioindicators in assessing the quality of freshwater ecosystems. In this study, we determined the differential gene expression profile of Protohermes costalis (Walker) (Megaloptera: Corydalidae) in response to cadmium (Cd) exposure by using transcriptome analysis. A total of 60,627 unigenes were obtained in the transcriptomes of 150 mg/liter (PL), 1,000 mg/liter (PH) CdCl2 treatment, and the no Cd control (PC). Differential expression gene (DEG) analysis by pairwise comparison identified 2,794 DEGs after filtering the noninsect genes and repetitive counts. 606 DEGs were shared in comparisons of PL versus PC and PH versus PC, with 165 DEGs consistently up-regulated and 441 down-regulated by both PL and PH. Six heat shock proteins (HSPs) in the HSP70 family were identified in P. costalis and PcosHSP68 was up-regulated by both PL and PH. Real-time quantitative polymerase chain reaction (RT-qPCR) confirmed that the expression levels of PcosHSP68 in PL and PH were higher than that of PC by 31 and 197%, respectively. These results showed that exposure to Cd altered the gene expression profiles of P. costalis and the transcriptome data presented in this study provide insight into future studying on molecular mechanisms of Cd toxicity to these insects. [ABSTRACT FROM AUTHOR]

Local communities and individual species jointly contribute to the overall beta diversity in metacommunities. However, it is mostly unknown whether the local contribution (LCBD) and the species contribution (SCBD) to beta diversity can be predicted by local and regional environmental characteristics and by species traits and taxonomic relatedness, respectively. We investigated the LCBD and SCBD of stream benthic diatoms and insects along a gradient of land use intensification, ranging from streams in pristine forests to agricultural catchments in southeast subtropical Brazil. We expected that the LCBD would be negatively related to forest cover and positively related to the most unique streams in terms of environmental characteristics and land use (hereafter environmental and land use uniqueness, respectively). We also expected that species with a high SCBD would occur at sites with reduced forest cover. We found that the LCBD of diatoms and insects was negatively related to forest cover. The LCBD of insects was also positively related to environmental and land use uniqueness. As forest cover was negatively related to uniqueness in land use, biologically unique streams were those that deviated from the typical regional land cover. We also found that diatom traits, insect traits, and taxonomic relatedness partly explained SCBD. Furthermore, the SCBD of diatoms was positively correlated with forest cover, but the inverse was found for insects. We showed that deforestation creates novel and unique communities in subtropical streams and that species that contribute the most to beta diversity can occur at opposite ends of a land use gradient. [ABSTRACT FROM AUTHOR]

The giant water bug, Lethocerus indicus (Lepeletier & Serville, 1825), is an aquatic true bug that has been included in the Vietnam Red Data Book since 1992 (“ca-cuong” in Vietnamese, “maeng-da” in Laos and Thailand). This insect also has been listed as an endangered species in Japan, Laos, and South Korea. This study aimed to (1) perform a genetic analysis to determine the species status of various populations of L. indicus in Southeast Asia, and (2) initially survey their distribution in Vietnam and Laos. Four populations were collected: two from the Vientiane Capital and Savannakhet Province areas of Laos, and two from the Vinh Phuc and Long An areas of Vietnam, respectively. Cytochrome oxidase subunit I (COI) fragments longer than 600 bps were amplified by polymerase chain reaction (PCR). Twelve nucleotide polymorphisms were found among these four populations. A maximum likelihood tree based on COI showed that the genetic distances among populations were very small, ranging from 0.2% to 1.1%, and were substantially distant from other populations of Lethocerus. Therefore, they are all considered to be conspecific and to represent L. indicus. [ABSTRACT FROM AUTHOR]