Groups Of Aquatic Insects Research Articles

Phylogenomics resolves a 100-year-old debate regarding the evolutionary history of caddisflies (Insecta: Trichoptera)

Trichoptera (caddisfly) phylogeny provides an interesting example of aquatic insect evolution, with rich ecological diversification, especially for underwater architecture. Trichoptera provide numerous critical ecosystem services and are also one of the most important groups of aquatic insects for assessing water quality. The phylogenetic relationships of Trichoptera have been debated for nearly a century. In particular, the phylogenetic position of the “cocoon-makers” within Trichoptera has long been contested. Here, we designed a universal single-copy orthologue and sets of ultraconserved element markers specific for Trichoptera for the first time. Simultaneously, we reconstructed the phylogenetic relationship of Trichoptera based on genome data from 111 species, representing 29 families and 71 genera. Our phylogenetic inference clarifies the probable phylogenetic relationships of “cocoon-makers” within Integripalpia. Hydroptilidae is considered as the basal lineage within Integripalpia, and the families Glossosomatidae, Hydrobiosidae, and Rhyacophilidae formed a monophyletic clade, sister to the integripalpian subterorder Phryganides. The resulting divergence time and ancestral state reconstruction suggest that the most recent common ancestor of Trichoptera appeared in the early Permian and that diversification was strongly correlated with habitat change.

Molecular identification of some species of dragonfly (Odonata: Anisoptera) using COXI gene and DNA barcodes from Basrah Province, Southern Iraq

The taxonomy of the Odonata group is still poorly understood; therefore, molecular identification has been developed to address the shortcomings of traditional taxonomy, such as misidentification and inconsistencies in reference databases. The mtCOXI gene has been used in animal barcoding studies because of its wide range of phylogenetic signals. Odonata, a diverse group of aquatic insects, has been studied at the molecular level to understand the evolutionary relationships between their species and global species. In the current study in Basrah Province, Iraq, we extracted mitochondrial DNA from adult and nymph Dragonflies and designed species-specific primers to distinguish some of the endemic species at the molecular level. This study identified five species, Crocothemis erythraea, Diplacodes trivialis, Orthetrum sabina, Trithemis annulata and Hemianax ephippiger. The DNA sequences were deposited in the NCBI database for the first time. The nucleotide sequences of the mtCOXI genes were analyzed via BLAST. The similarity results ranged from 91.8% to 100%, indicating related species on the basis of the branches of the phylogenetic tree. The molecular identity of the selected species was confirmed, and DNA barcodes for Anisoptera species from Basrah Province were successfully developed and documented in GenBank and IBIN.

Distribution and habitat database of fluvial Plecoptera, Trichoptera and Coleoptera from Sierra Nevada, Spain

Sierra Nevada (southern Iberian Peninsula) harbours a great biodiversity and the studies on some aquatic insect groups have been and continue to be numerous there. This database brings together information on Plecoptera, Trichoptera and Coleoptera inhabiting running waters of this mountain system above 800 m of altitude. It includes data on the number, life stage and sex of individuals as well as the available information on abiotic characteristics of their habitats. The dataset is composed of 1,718 sampling events carried out between 1901 and 2022 in approximately 60 different water bodies, 15,347 occurrences pertaining to more than 203,000 individuals, and 10,173 records of associated measurements (23 physico-chemical parameters). The dataset is the result of a comprehensive review of scientific literature and of integrating data from recent research projects and the Sierra Nevada Global-Change Observatory’s long-term monitoring data. This information is valuable for those studying past distributions and abundances of the species in the dataset, for building predictive models or just studying temporal trends in the current context of climate change.

Diversity and Ecological Distribution of Plecoptera of Minas Gerais, Brazil.

The order Plecoptera constitutes a relatively small group of aquatic insects, encompassing 17 extant families and comprising over 4400 valid species. In Brazil, the number of valid extant species is 207, located in two families: Perlidae (149) and Gripopterygidae (58). Despite extensive research on the southeastern region of Brazil, there is a notable scarcity of comprehensive studies consolidating geographical records and species richness of Plecoptera in the state of Minas Gerais. This study seeks to increase and refine our understanding of Plecoptera within Minas Gerais, focusing on its diversity and distribution. The initial phase involved a thorough review of articles documenting Plecoptera species in the state. Subsequently, biological material from the Museum of Entomology at the Federal University of Viçosa collection was meticulously identified, and its geographical records were incorporated. Utilizing this dataset, we compiled an updated list of Plecoptera species documented in Minas Gerais. Geographical coordinates of collection points were then mapped and graphically represented to elucidate the geographic and altitudinal distribution of these species. A total of 42 Plecoptera species were identified within the state of Minas Gerais, adding many occurrence records and documenting the first record of Gripopteryx pinima for the state. Despite these advancements, knowledge gaps persist, particularly in the mesoregions of Triângulo/Alto Paranaíba, Oeste de Minas, Vale do Mucuri, and Campo das Vertentes. This endeavor serves as an initial foundation to stimulate further collections and investments in undersampled areas, fostering future monitoring and conservation initiatives for aquatic environments.

Long-Term Chironomid Emergence at a Karst Tufa Barrier in Plitvice Lakes National Park, Croatia.

Chironomids are found in all types of freshwater habitats; they are a ubiquitous and highly diverse group of aquatic insects. Plitvice Lakes National Park is the oldest and largest national park in Croatia and consists of numerous and diverse freshwater habitats, making the area an ideal location for long-term research into the chironomid emergence patterns and phenology. The main objectives of this study were to identify the composition of the chironomid community, determine the phenology of the identified species, and assess the main factors influencing their emergence in Plitvice Lakes. During 14 years of research, more than 13,000 chironomids belonging to more than 80 species were recorded. The most abundant species was found to be Parametriocnemus stylatus. The highest abundance of chironomids was recorded in lotic habitats with faster water current over substrates of moss and algae and pebbles. Water temperature and the availability of organic matter were found to be the main factors that drive chironomid emergence at the tufa barrier studied. In the last years of this study, a prolonged flight period was observed. Although this is not statistically significant (at this stage of the study), it could be due to a higher water temperature in winter.

Assessment of functional feeding groups (FFG) structure of aquatic insects in North- western Rif - Morocco.

The involvement of trait-based approaches is crucial for understanding spatial patterns, energy flow and matter transfer in running water systems, which requires consistent knowledge of the functional structures of aquatic communities, with the advantage of combining physical properties and behavioral mechanisms of food acquisition rather than the taxonomic group. The present study indicated how functional feeding groups may be used as a proxy for classical taxonomic evaluation, as well as the potential interest in incorporating them as indicators of anthropogenic stressors. The composition and abundance of the functional feeding groups of aquatic insects were examined from September 2021 to August 2022 along the Western Rif Region. Benthic samples were collected from nine sampling points in the studied area using a Surber sampler with a mesh size of 500 µm and a diameter of 20*20 cm. The stations included in this work were chosen for their accessibility as well as their position on the hydrographic systems. The abundance of sampled aquatic organisms in the whole study area revealed 5,342 individuals belonging to 60 families and seven orders of aquatic insects, classified into five feeding functional groups. In terms of abundance, Collector-gatherers (Ephemeroptera and Diptera) were the most abundant trophic group at most of the sites, with a proportion of 38.47%. Predators (Coleoptera, Hemiptera and Odonata) were the second group at all sites, followed by Collector-filters, accounting for 39.53%, 28.14% and 22.37% respectively, while Scarpers and Shredders had the lowest representation across all sites with 4.16%. The high number of registered Collectors could be related to their ability to feed on a diverse range of food items compared to the remaining trophic guilds. According to the Canonical Correspondence Analysis results, physicochemical (i.e. T, pH, BOD5, Cl- and NO3-) and hydromorphological (i.e. current velocity and depth) variables were amongst the key predictors of shaping the functional structure of aquatic biota during this investigation. It is highly recommended to carry out suitable measures to largely attenuate anthropogenic pressures in order to preserve the integrity of freshwater bodies and their biota.

Effects of urbanization, biotic and abiotic factors on aquatic insect diversity in urban ponds

Urbanization leads to drastic modifications of the terrestrial and aquatic environment. However, urban ponds may provide valuable habitats for different taxa, including aquatic insects and amphibians. We aim to understand how a set of biotic and abiotic factors influence aquatic insect diversity in 18 urban ponds in the German metropolis Berlin, one of the greenest whilst most densely populated European cities. Greenspace is important for the terrestrial stages of some aquatic insects and amphibians, providing crucial resources. Thus, greenspace was assumed to have positive effects on aquatic insect diversity, whereas built-up area was assumed to affect diversity negatively. Because some aquatic insects prey on tadpoles, their abundance and diversity were assumed to depend on tadpole abundance, which in turn, depends on other food (i.e., phytoplankton) availability in ponds. We visited the ponds twice a year, in spring and summer, and collected data on aquatic insects that are known to prey on tadpoles, tadpole abundance, phytoplankton biomass, the presence or absence of large insect predators, as well as physical–chemical parameters. We assumed higher total aquatic insect abundance, genera richness, alpha-diversity, and evenness, as well as abundance and genera richness of different aquatic insect taxonomic groups to be associated with high tadpole abundance in ponds surrounded by high amount of greenspace and low levels of built-up area. Accordingly, we expected aquatic insects to be modulated by phytoplankton biomass, the presence of newts and fish, and to be affected by ponds’ abiotic conditions. Our results showed that biological interactions and abiotic water conditions override urban effects in ponds’ terrestrial surroundings on aquatic insect diversity levels, whereas aquatic insects’ taxonomic groups responded differently on different land-use types around ponds. We explain our findings due to different dependences and demands towards terrestrial and/or aquatic habitats by different taxonomic groups of aquatic insects, and differences in their colonization behavior.

Bioconcentrations, depuration, shift in metabolome and a behavioural response in the nymphs of the dragonfly Aeshna cyanea (Müller, 1764) to environmentally relevant concentrations of methamphetamine

Methamphetamine (MEA) is commonly detected in municipal wastewater. It causes imbalances in the system of neurotransmitters as well as several other adverse effects on human health. The aim of this study was to investigate bioconcentration and depuration rates at an environmentally relevant concentration of 1 µg·L−1 in Aeshna cyanea nymphs exposed to MEA for six days followed by three days of depuration. The metabolomes of nymphs sampled during exposure and depuration were compared using non-targeted screening. Concurrently, a behavioural experiment was run to evaluate the effect of MEA on movement. Since most samples were below the limits of quantification (LOQs) – MEA was quantified in only four out of the 87 samples and only during the first 24 h of exposure at concentrations at LOQ level – we estimated maximal possible bioconcentration factor (BCF) on 0.63 using the LOQ. An MEA metabolite – amphetamine – was not detected in any sample at levels above their LOQs. From 247 up to 1458 significant down- and up-regulated metabolite signals (p ≤ 0.05) were detected by non-targeted screening during initial times of exposure and depuration. Numbers of significant down- and/or up-regulated signals in metabolomes (p ≤ 0.05) calculated for particular sampling times possibly correlated with the size of the effect on movement recorded at the same times. In the MEA treatment, movement was not significantly greater during exposure (p > 0.05) but was significantly lower during depuration (p < 0.05). This study shows how MEA acts on dragonfly nymphs, an ecologically important group of aquatic insects with a high trophic level.

The little-known larval morphology of two stoneflies of Styloperlidae (Insecta: Plecoptera) in China

The stoneflies are a relatively ancient group of aquatic insects. The larvae of stoneflies are exclusively aquatic and are important bioindicators for water quality changes. However, the identification and classification of stonefly larvae are much more difficult than the adults, due to the lack of sufficient descriptions for most stonefly taxa. Styloperlidae is an endemic stonefly family in South Asia. The larval morphology of this family remains less clear in comparison with their adults. In this paper, the larvae of Styloperla inae Chao, 1947 and Cerconychia flectospina Wu, 1962 are described and illustrated based on specimens from China. Their morphology corresponds with the proposed diagnostic larval characters of Styloperlidae in previous studies. Additional auxiliary characters useful for the identification of larvae in Styloperlidae are discussed. The larvae of S. inae and C. flectospina exhibit subtle morphological differences but can be easily distinguished by the presence or absence of dark sclerites on all the thoracic sternal pits.

Mandibular shape as a proxy for the identification of functional feeding traits of midge larvae (Diptera: Chironomidae)

The identification of functional feeding traits in aquatic macroinvertebrates often requires a morphology-based identification of species, which is important for trait-based methods of biological assessment. The extent of functional homogenization is compared along scales of impairment, where trait-based information is used as an input in models that examine degradation pathways. However, trait-based information is not always readily available for all groups of aquatic insects, especially for species diverse families, such as chironomids (Diptera: Chironomidae). Taxonomic challenges and ambiguous traits complicate the use of chironomid larvae in trait-based bioassessment. Here, we examine the use of geometric morphometric analysis (GMA), deep learning (Convolutional Neural Networks), and computer vision (deep CNN) applied to the mouthparts (mandibles) of chironomid larvae as a proxy for identifying the relationship between the functional morphology and food acquisition behaviour. We determined the variability in morphology of mandibles for 23 taxa of chironomid larvae from different genera, subfamilies, and their Functional Feeding Group (FFG). Analysis using GMA showed that the five different FFGs examined had different mandibular traits that significantly varied in shape and size. A deep CNN model was then built that was able to classify the 23 taxa into their respective FFG automatically with 92.31 % accuracy. A gradient-weighted Class Activation Mapping (Grad-CAM) algorithm found that the most important part of mandibles for classification were the gula and mandibular joint. We introduced three additional species to the deep CNN models to test whether automatic classification would directly and automatically identify traits of the specimens independently from taxonomic identification. The deep CNN process avoids issues surrounding both taxonomic identification and previous knowledge of a specific taxon’s feeding trait, and in all cases the model classified taxa correctly based on their mandibular traits. The use of deep learning approaches could substantially enhance the use of trait-based approaches and increase the reliability and use of chironomids in bioassessment.

Nutritional Composition, Phenolic Compounds and Antioxidant Activity of Different Samples of Water Boatmen Eggs (Hemiptera: Corixidae).

The group of aquatic insects collectively called "water boatmen" or "Axayacatl" (Hemiptera: Corixidae) and their eggs, called "Ahuahutle", have been consumed and cultivated since the pre-Hispanic era in Mexico. Nevertheless, food composition databases contain limited information on the nutritional composition of these eggs. This work evaluates the macronutrients and bioactive compounds of water boatmen eggs obtained from three different locations in Mexico. The primary analyses to be determined for the first time were some bioactive compounds in the eggs, such as phenolic compounds, total flavonoids, condensed tannins content, antioxidant activity (DPPH and ABTS), and, additionally, fatty acids and proximal composition. The results showed that the sample from Hidalgo (AMC) presented the highest number of phenolic compounds (855.12 ± 0.52), followed by ALT (125.52 ± 0.05) and, with the lowest amount, AMT (99.92 ± 0.13), all expressed in an mg GAE/g sample. ALT indicated the highest mol TE/g sample concentration for ABTS (25.34 ± 0.472) and DPPH (39.76 ± 0.054), showing a significant difference in the DPPH method with the AMT samples. The three Corixidae egg samples had between 15 to 18 different fatty acid profiles, and there were statistically significant differences (Student's t-test ≤ 0.05) between the means using MSD. The total fats of the three samples were between 12.5 and 15.5 g/100 g dry basis. In addition, Corixidae eggs are excellent protein sources. Thus, water boatmen's eggs can be considered to be a food rich in bioactive compounds.

50%, not great, not terrible: Pan-European gap-analysis shows the real status of the DNA barcode reference libraries in two aquatic invertebrate groups and points the way ahead

The essential key to routine molecular species identification (DNA barcoding/metabarcoding) is the existence of an error-free DNA barcode reference library providing full coverage of all species. Published studies generally state the need to produce more barcodes, and control their quality, but unfortunately, the number of barcoded species is still low. However, to initiate real progress, we need to know where the gaps lie, how big they are and why they persist. Our aims were to draw and understand the current state of knowledge regarding species diversity, distribution, and barcode coverage, and offer solutions for improvement. In this study, we used two groups of aquatic insects, beetles and true bugs. We have compiled and critically evaluated an essentially complete and up-to-date European list, containing 1527 species. The list served as a basis for the barcode gap analyses in the Barcode-of-Life-Data-System (BOLD) conducted in three subsequent years (2020–2022). The overall barcode coverage of the pan-European fauna was around 50 % in both groups. The lowest coverage was in the Mediterranean, the Balkans and South-eastern Europe. The coverage in each country depended significantly on the local diversity, the number of rare, endemic species and the similarity of its fauna to that of the most active barcoding European countries. Gap analyses showed a very small increase in species coverage (<1 % in European aquatic beetles) despite an ~25 % increase in the number of barcodes. Hence, it is clear that future barcoding campaigns must prioritise quality over quantity. To visibly improve reference libraries, we need to increase the involvement of taxonomic experts and focus on targeted studies and underexplored but biodiversity-rich areas.

Massive gene rearrangements of mitochondrial genomes and implications for the phylogeny of Trichoptera (Insecta)

AbstractMitochondrial genomes have been widely used for phylogenetic reconstruction and evolutionary analysis in various groups of Insecta. Gene rearrangements in the mitogenome can be informative characters for phylogenetic reconstruction and adaptive evolution. Trichoptera is one of the most important groups of aquatic insects. Prior to this study, complete mitogenomes from Trichoptera were restricted to eight families, resulting in a biased view of their mitogenome structure and evolution. Here, we assemble new mitogenomes for 66 species by high‐throughput sequencing. The mitogenomes of 19 families and 47 genera are documented for the first time. Combined with 16 previously published mitogenomes of Trichoptera, we find 14 kinds of gene rearrangement patterns novel for Trichoptera, including rearrangement of protein‐coding genes, tRNAs and control regions. Simultaneously, we provide evidence for the occurrence of tandem duplication and non‐random loss events in the mitogenomes of three families. Phylogenetic analyses show that Hydroptilidae was recovered as a sister group to Annulipalpia. The increased nucleotide substitution rate and adaptive evolution may have affected the mitochondrial gene rearrangements in Trichoptera. Our study offers new insights into the mechanisms and patterns of mitogenome rearrangements in Insecta at large and into the usefulness of mitogenomic gene order as a phylogenetic marker within Trichoptera.

Assessing spatial deposition of aquatic subsidies by insects emerging from agricultural streams.

The role of winged aquatic insects that emerge from streams and subsidize terrestrial ecosystems has been demonstrated for natural forest landscapes, but almost no information is available for intensive agricultural landscapes. This study is the first to estimate aquatic subsidies provided by flying insects that emerge from streams and land on cropland. We investigated three major groups of aquatic insects - Trichoptera, Ephemeroptera and Chironomidae (Diptera) - that emerged from 12 third-order temperate, agricultural streams. We simultaneously monitored their emergence using floating traps and their terrestrial dispersal using passive interception traps. We estimated that the annual aquatic emerging dry mass (DM) of these groups varied from 1.4-7.5 g m-2 yr-1, depending on the stream. We used a Bayesian approach to estimate parameters of the terrestrial dispersal function of each group. We combined emerging DM and the dispersal parameters to estimate how terrestrial deposition of aquatic insect DM varied with increasing distance from streams. The results highlighted that emerging DM and dispersal to land could be higher in intensive agricultural landscapes than that previously described in natural settings. We estimated that 12.5 kg ha-1 yr-1 of winged aquatic insect DM fell to the ground 0-10 m from stream edges, composed mainly of Ephemeroptera and Trichoptera. We also estimated that 2.2 kg DM ha-1 yr-1 fell 10-50 m from the stream, especially small-bodied species of Chironomidae, throughout the year, except for the coldest weeks of winter. By influencing aquatic insect communities that emerge from streams, intensive agricultural practices change the magnitude and spatial extent of aquatic subsidy deposition on land. Implications for terrestrial food webs and ecosystem services provided to agriculture are discussed.

Lack of congruence between fundamental and realised aridity niche in a lineage of water beetles

Abstract Coping with aridity is a physiological challenge for all organisms, including freshwater ones. Aridity shapes distributions of aquatic species at fine and large geographical scales. Specifically, for aquatic beetles, the desiccation resistance of the adults is a potential constraint for the colonisation of arid regions. We assessed the congruence between the fundamental and realised aridity niche in eight species of a Palearctic lineage of water beetles (subgenus Lumetus, genus Enochrus, family Hydrophilidae). We also estimated the relative explanatory capacity of aridity‐related versus other environmental variables in species distributions. Most of the species, even those most sensitive to desiccation stress in laboratory experiments, occur in areas with high aridity within the Palearctic region. Our results suggest a lack of association between the physiological (desiccation resistance) and environmental distance matrix (realised aridity niche), or between either of these and phylogenetic distances. Aridity‐related variables had generally a similar explanatory capacity in explaining the distribution of species than non‐related ones. Our results indicate that desiccation resistance has not been an important physiological constraint for the colonisation of arid environments by this clade and suggest that other non‐physiological factors are more important in shaping their distributions along aridity gradients. The studied beetle lineage might conserve a high basal desiccation resistance from relatively recent terrestrial ancestors, which could have provided a physiological advantage for the colonisation of arid areas. Further research could shed light on whether these unexpected results are common to other groups of aquatic insects living in arid areas or are particular to this group of beetles.

Structuring functional groups of aquatic insects along the resistance/resilience axis when facing water flow changes.

Understanding how differences in intensity and frequency of hydrological disturbances affect the resistance and resilience of aquatic organisms is key to manage aquatic systems in a fast‐changing world. Some aquatic insects have strategies that improve the permanence (resistance), while others use strategies that favor recolonization (resilience). Therefore, we carried out a manipulative experiment to understand the influence of functional characteristics of aquatic insects in their permanence and recolonization against hydrological disturbances in streams in the biodiversity hotspot of the Cerrado of Brazil. We placed 200 artificial substrates in five streams and submitted them to changing water flow regimes that differed both in frequency and intensity, and we observed the response of the aquatic community for 39 days. We used a hierarchical Bayesian approach to estimate the probabilities of permanence and recolonization of each life strategy group (nine groups). We observed that the most intense changes in the water flow tended to affect the permanence of almost all groups, but the intensity of this effect reduced over time. On the other hand, less frequent disturbances, regardless of intensity, tended to reduce the permanence of most groups of aquatic insects over time. The different effects of disturbance intensity may have been related to a greater recolonization capacity of some groups. The results we present are worrisome in a scenario of reduced riparian vegetation around streams and with the expectation of precipitation becoming more concentrated in shorter periods of time due to climate change in the Cerrado hotspot, reducing the occurrence of many groups of aquatic insects in their habitat, particularly those with traits associated with resistance against hydrological disturbance.

Land use changes disrupt streams and affect the functional feeding groups of aquatic insects in the Amazon

Land use changes disrupt streams and affect the functional feeding groups of aquatic insects in the Amazon

Aquatic Insect Bioconstructions Modify Fine‐Sediment Entrainment and Mobility

AbstractThe importance of two‐way interactions between animals and the physical hydraulic and sedimentological environment are increasingly recognized (e.g., zoogeomorphology). Caddisflies (Trichoptera) are a group of aquatic insects known for their bioconstructions, particularly cases built from fine sediment and silk. Caddisfly cases differ in size, shape and density from the incorporated sediment, and case construction may therefore affect the mobility of these sediments in rivers. However, although communities of caddisfly often use substantial quantities of sediment in case construction, the effect of these bioconstructions on sediment transport in rivers is unknown. We use a flume experiment to compare the bed shear stress required to transport (a) empty caddisfly cases and (b) individual sediment particles, following disaggregation from the case. The cases of three species were considered; two that construct different styles of tubular case (Potamophlax latipennis and Sericostoma personatum) and one that builds a domed case (Agapetus fuscipes). P. latipennis and S. personatum cases were easier to entrain than the sediment grains incorporated into them, whilst A. fuscipes cases were not. Despite their low mass, A. fuscipes cases required the most shear stress to transport them because their domed shape impeded rolling. These findings are important to understand how differences in case design between species, reflect different adaptation strategies to the turbulent hydraulic river habitat. Furthermore, the results suggest that un‐attached tubular caddisfly cases may be preferentially transported over other particles on the river bed and thus, where caddisfly occur in high abundance, they may increase fluvial entrainment of sand.

Gene Flow and Diversification in Himalopsyche martynovi Species Complex (Trichoptera: Rhyacophilidae) in the Hengduan Mountains

Simple SummaryHimalopsyche is a group of aquatic insects endemic to the Hengduan Mountains, of which species are usually easily identifiable based on male genitalia, except for a few morphologically variable groups including the Himalopsyche martynovi complex. In order to clarify species boundaries within this complex, we investigated its evolutionary history (phylogenetics and gene flow analyses) using a large genomic dataset (~500,000 sites). We found three clades in the Himalopsyche martynovi complex, one of which being very variable morphologically while being involved in gene flow with other related lineages. When interpreted in the light of past geological, climatic and palaeohydrological changes, our study suggests that biological novelty—here, trait variation and recombination—may have been acquired via hybridization and represent a source of mountain biodiversity.The Hengduan Mountains are one of the most species-rich mountainous areas in the world. The origin and evolution of such a remarkable biodiversity are likely to be associated with geological or climatic dynamics, as well as taxon-specific biotic processes (e.g., hybridization, polyploidization, etc.). Here, we investigate the mechanisms fostering the diversification of the endemic Himalopsyche martynovi complex, a poorly known group of aquatic insects. We used multiple allelic datasets generated from 691 AHE loci to reconstruct species and RaxML phylogenetic trees. We selected the most reliable phylogenetic tree to perform network and gene flow analyses. The phylogenetic reconstructions and network analysis identified three clades, including H. epikur, H. martynovi sensu stricto and H. cf. martynovi. Himalopsyche martynovi sensu stricto and H. cf. martynovi present an intermediate morphology between H. epikur and H. viteceki, the closest known relative to the H. martynovi-complex. The gene flow analysis revealed extensive gene flow among these lineages. Our results suggest that H. viteceki and H. epikur are likely to have contributed to the evolution of H. martynovi sensu stricto and H. cf. martynovi via gene flow, and thus, our study provides insights in the diversification process of a lesser-known ecological group, and hints at the potential role of gene flow in the emergence of biological novelty in the Hengduan Mountains.

The taxonomical and functional diversity of three groups of aquatic insects in rheocrene karst springs are affected by different environmental factors

Karst springs represent valuable and often the most threatened habitats in the riverine landscape. Unlike other stream habitats, they have several specifics that determine their insularity in the river continuum, e.g., high seasonal thermal and chemical stability. The presented study aimed to find out the taxonomical and functional richness of three groups of aquatic insects (Ephemeroptera, Plecoptera and Trichoptera) in the Western Carpathians karst springs, as well as uncover the mechanism of the EPT community assembly. Low within-site species richness was generally found, however, there was high between-site diversity and thus high total diversity of the studied groups of benthic invertebrates as well. Species richness of the EPT community was higher in larger and colder springs: those with lower concentrations of CO2 and Fe, as well as higher concentrations of SO42−. Analysis of functional richness, as well as functional dispersion, did not reveal any clear assembly mechanism in the spring EPT community; however, both analyses indicated a higher proportion of environmental filtering there. Unlike the taxonomic richness, the functional richness of the EPT community was significantly higher in small and medium springs with higher water temperatures, as well as in springs with the presence of deadwood. Between-site dissimilarities in the functional composition of EPT were significantly correlated with environmental differences of springs, which determined variables such as spring size and temperature, as well as the concentration of CO2 and SiO2.