Aquatic Insect Communities Research Articles

Predicting present and future habitats using LiDAR to integrate research and monitoring with landscape analyses

Managed forests contribute to both economic and non-timber values, but the ecological role of managed, including planted, forests to biodiversity objectives at the landscape scale needs to be better understood. In this project in collaboration with J.D. Irving, Limited, we: 1) used airborne LiDAR and field data to identify terrestrial habitats; 2) monitored selected taxa by 18 stand type/seral stage habitat types in intensively and extensively managed forests and reserves; 3) assessed effects of management intensity on water quality and aquatic habitat; and 4) projected forest and wildlife habitat under planned management and natural disturbance scenarios. Taxa studied included songbirds, bryophytes and beetle species associated with mature-overmature forests, and several listed ground vegetation species. LiDAR-based enhanced forest inventory provided forest structure variables that improved bird habitat models and spatial predictions of bird habitat, metrics explaining bryophyte composition and richness, and variability in beetle abundance and richness. There was no evidence of negative landscape-level effects of increasing management intensity on bird communities in mature forest stands, suggesting that managed spruce-fir-tolerant hardwood landscapes provide habitat for bird species that need old forest. Richness, diversity, and composition of bryophyte guilds in reference stands in Mount Carleton Provincial Park unmanaged reserve did not differ from stands in the intensively managed District. The landscape focus and stratification into stand type/seral stages were important to understand habitat requirements. Catchments with greater forest management did not show any consistent signs of biological impairment from smaller to larger scales, and all sites had good or very good biological water quality based on the aquatic insect communities. This study helped to evaluate forest management effects on habitat areas, detected with airborne LiDAR data, that need to be addressed to enhance decision making processes.

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

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

Effect of water edge structure on aquatic insect communities in wetland biotopes created for biological conservation: research performed immediately after field development

Effect of water edge structure on aquatic insect communities in wetland biotopes created for biological conservation: research performed immediately after field development

Thermal tolerance does not explain the altitudinal segregation of lowland and alpine aquatic insects

Elevation gradients provide powerful study systems for examining the influence of environmental filters in shaping species assemblages. High-mountain habitats host specific high-elevation assemblages, often comprising specialist species adapted to endure pronounced abiotic stress, while such harsh conditions prevent lowland species from colonizing or establishing. While thermal tolerance may drive the altitudinal segregation of ectotherms, its role in structuring aquatic insect communities remains poorly explored. This study investigates the role of thermal physiology in shaping the current distribution of high-mountain diving beetles from the Sierra Nevada Iberian mountain range and closely related lowland species. Cold tolerance of five species from each altitudinal zone was measured estimating the supercooling point (SCP), lower lethal temperature (LLT) and tolerance to ice enclosure, while heat tolerance was assessed from the heat coma temperature (HCT). Alpine species exhibited wider fundamental thermal niches than lowland species, likely associated with the broader range of climatic conditions in high-mountain areas. Cold tolerance did not seem to prevent lowland species from colonizing higher elevations, as most studied species were moderately freeze-tolerant. Therefore, fundamental thermal niches seem not to fully explain species segregation along elevation gradients, suggesting that other thermal tolerance traits, environmental factors, and biotic interactions may also play important roles.

No effects of macroconsumer exclusion on macroinvertebrate functional composition in Brazilian karst streams along a gradient of riparian forest loss

AbstractDegradation and loss of riparian vegetation are some of the main drivers of change in the trophic interactions among aquatic macroconsumers. These changes can often have major consequences for biodiversity and stream ecosystem functioning. Yet, many aspects of food‐web dynamics are still not well understood, including how food webs among tropical streams respond to riparian vegetation loss. We examined the role of macroconsumers on community structure of functional feeding groups of benthic macroinvertebrates along a forest cover gradient within the Bodoquena Plateau, Brazil. We compared the effect of excluding macroconsumers (using electric fences) on functional feeding groups to those in controls within seven karst streams along a gradient of riparian vegetation cover. Aquatic insect and gastropod communities were dominated by groups of collector‐gatherers, scrapers, and predators across all sites. The exclusion of macroconsumers did not lead to an increase in the abundance of macroinvertebrates and was not affected by the forest cover during the experiment. These findings demonstrated that the experimental exclusion of macroconsumers resulted in a lack of or negligible effect on functional feeding groups along the gradient of forest cover. It is important to consider the specificity of trophic relationships to fully understand the effects of vegetation loss on streams where complex groundwater hydrology can also affect food webs such as in karst terrain.Abstract in Portuguese is available with online material.

Culex pipiens and Culex restuans larval interactions shape the bacterial communities in container aquatic habitats.

Container aquatic habitats host a community of aquatic insects, primarily mosquito larvae that browse on container surface microbial biofilm and filter-feed on microorganisms in the water column. We examined how the bacterial communities in these habitats respond to feeding by larvae of two container-dwelling mosquito species, Culex pipiens and Cx. restuans. We also investigated how the microbiota of these larvae is impacted by intra- and interspecific interactions. Microbial diversity and richness were significantly higher in water samples when mosquito larvae were present, and in Cx. restuans compared to Cx. pipiens larvae. Microbial communities of water samples clustered based on the presence or absence of mosquito larvae and were distinct from those of mosquito larvae. Culex pipiens and Cx. restuans larvae harbored distinct microbial communities when reared under intraspecific conditions and similar microbial communities when reared under interspecific conditions. These findings demonstrate that mosquito larvae play a major role in structuring the microbial communities in container habitats and that intra- and interspecific interactions in mosquito larvae may shape their microbiota. This has important ecological and public health implications since larvae of the two mosquito species are major occupants of container habitats while the adults are vectors of West Nile virus.

Local factors and bionomic characteristics determining the occurrence of semiaquatic bugs in streams of Central Amazonia

Abstract Individual responses to changes in the environment by different species drive a better understanding of the dynamics of diversity and habitat filtering. Hypotheses based on functional and morphometric characteristics of the species are especially useful for accounting for different interpretations of biological responses. This study aimed to determine the responses of semiaquatic species of insects to habitat changes from the elaboration of hypotheses based on the importance of species traits facing environmental variations. We tested these hypotheses with maximum likelihood models to explain the occurrence of the species in streams of the central Amazon region. In a total of 17 collected Gerromorpha species, we used 14 to develop five predictive models of occurrence considering the bionomic characteristics of each species and their possible relationships with habitat changes in 33 streams in the central Amazon region. We used maximum likelihood models to assess the fit of the models to the observed occurrence, with environmental characteristics as covariates affecting the occurrence probability, and sampling effort affecting the detection probability. A total of five species exhibited changes in the probability of occurrence in streams related to an environmental condition (riparian forest disturbance, flow heterogeneity, and surface habitat heterogeneity). The probability of occurrence tended to reduce for four of the five species and increase for one with increase of environmental impacts. Furthermore, the sampling effort covariate did not affect the probability of detection in most species, indicating that the group showed a high detection. The use of functional characteristics of Gerromorpha species to develop ecological hypotheses proved relevant and indicated unexpected relationships, expanding our knowledge of this community of aquatic insects. Therefore, including the individual responses of organisms to environmental variations helps in studies on aquatic biodiversity, both for basic ecology and for conservation and bioassessment.

Spatial and Environmental Influence on the Community of Aquatic Insects in Atlantic Forest Streams

Purpose: Investigate the influence of environmental variables and spatial autocorrelation on aquatic insect communities within the same water flow in Atlantic Forest streams. Theoretical framework: The organisms in lotic environments are influenced by both local and non-local factors, in addition to other processes, which result from the dynamics of the environment. Alterations in these factors can provide evidence regarding the organization of aquatic communities. Given the high sensitivity insect are used in ecosystems quality studies around the world. Method: Sampling campaigns were conducted every three months. A total of twenty-four samples were collected across four campaigns and six collection sites were established along the same stream. In-situ measurements of physical and chemical variables were performed. The environmental quality of the surroundings was assessed using the Habitat Integrity Index. Results and conclusion: No spatial dependence was found between the sampling sites. Closer points no longer exhibited resemblance. For the studied situation, the surrounding and turbidity have a stronger relationship with the biota, acting as environmental filters and suggesting that the organization of is driven by local environmental conditions. Environments that are locally less disturbed are more influential in shaping for aquatic insect communities. Thus, considering the effect of habitats on organisms and recognizing the importance of local conservation efforts for preserving the aquatic biodiversity of the Atlantic Forest biome, we emphasize need for the implementation permanent monitoring programs in hydrographic basins, mainly for the BHRA, and the development of strategies aimed at minimizing the impacts on these environments. Research implications: We affirm the applicability of aquatic insects as valuable indicators for assessing the quality and biodiversity of streams and suggest studies with these organisms as a strategy to support management in freshwater environments. Originality/value: Studies that evaluate water bodies and their surroundings are essential in view of the pressures exerted through the different land uses. The study region deserves attention in view of the implementation of large constructions.

Diversity Analysis of Adult Chironomidae in the Lake Victoria Basin of Kenya

Chironomidae commonly inhabits most aquatic habitats and often dominate aquatic insect communities in abundance and species richness. Despite their ecological importance, the diversity and distribution of chironomids in the Lake Victoria ecosystem of Kenya have not been studied to date. Here we report on the diversity and distribution of adult Chironomidae in Usenge, Mbita and Ogal beaches of the Lake Victoria ecosystem in Kenya using morphological features and sequence data of Cytochrome c oxidase subunit I (COI) gene. Wing venation-based microscopic characterization identified four genera, Tanypus, Coelotanypus, Dicrotendipes and Chironomus. The COI gene barcoding further revealed several species, including Kiefferulus brevibucca, Chironomus flaviplumus, Polypedilum fuscovittatum, Polypedilum sp. and Dicrotendipes sp. The identified species were grouped into three clusters based on neighbor-joining phylogenetic approach. Differences in species richness were observed among the three study sites, with Mbita exhibiting the highest species richness. The evolutionary analysis revealed relatedness among all the identified species, suggesting a shared recent common ancestor. Unlike previous studies, this study represents thefirst report on detailed characterization of Chironomidae in the Lake Victoria ecosystem of Kenya. Moreover, this study serves as a first step towards a comprehensive understanding of the range of species of Chironomidae inhabiting this ecosystem.

Interactions between diurnal winds and floodplain mosaics control the insect boundary layer in a river corridor

Insect flight along river corridors is a fundamental process that facilitates sustainable succession and diversity of aquatic and terrestrial insect communities in highly dynamic fluvial environments. This study examines variations in the thickness of the insect boundary layer (i.e., the pre-surface atmosphere layer in which air velocity does not exceed the sustained speed of flying insects) caused by interactions between diurnal winds and the heterogenous habitat mosaics in the floodplain of a braided river. Based on advective–diffusive theory, we develop and test a semi-empirical model that relates vertical flux of flying insects to vertical profiles of diurnal winds. Our model suggests that, in the logarithmic layer of wind, the density of insect fluxes decreases exponentially with the altitude due to the strong physical forcing. Inside the insect boundary layer, the insect fluxes can increase with the altitude while the winds speed remains nearly constant. We suggest a hypothesis that there is a close correspondence between the height of discontinuity points in the insect profiles (e.g. points with abrupt changes of the insect flux) and the displacement heights of the wind profiles (e.g. points above which the wind profile is logarithmic). Vertical profiles were sampled during three time-intervals at three different habitat locations in the river corridor: a bare gravel bar, a gravel bar with shrubs, and an island with trees and shrubs. Insects and wind speed were sampled and measured simultaneously over each location at 1.5-m intervals up to approximately 17 m elevation. The results support our working hypothesis on close correspondence between discontinuity and displacement points. The thickness of the insect boundary layer matches the height of the discontinuity points and was about 5 m above the bare gravel bar and the gravel bar with shrubs. Above the island, the structure of the insect boundary layer was more complex and consisted of two discontinuity points, one at the mean height of the trees’ crowns (ca. 15 m), and a second, internal boundary layer at the top of the shrubs (ca. 5 m). Our findings improve the understanding of how vegetation can influence longitudinal and lateral dispersal patterns of flying insects in river corridors and floodplain systems. It also highlights the importance of preserving terrestrial habitat diversity in river floodplains as an important driver of both biotic and abiotic (i.e., morphology and airscape) heterogeneity.

Shifting taxonomic and functional community composition of rivers under land use change.

Land use intensification has led to conspicuous changes in plant and animal communities across the world. Shifts in trait-based functional composition have recently been hypothesized to manifest at lower levels of environmental change when compared to species-based taxonomic composition; however, little is known about commonality in these responses across taxonomic groups and geographic regions. We investigated this hypothesis by testing for taxonomic and geographic similarities in the composition of riverine fish and insect communities across gradients of land use in major hydrologic regions of the conterminous United States. We analyzed an extensive dataset representing 556 species and 33 functional trait modalities from 8,023 fish communities, and 1,434 taxa and 50 trait modalities from 5,197 aquatic insect communities. Our results demonstrate abrupt threshold changes in both taxonomic and functional community composition due to land use conversion. Functional composition consistently demonstrated lower threshold responses compared to taxonomic composition for both fish (urban p = 0.069; agriculture p = 0.029) and insects (urban p = 0.095; agriculture p = 0.043) communities according to gradient forest models. We found significantly lower thresholds for urban versus agricultural land use for fish (taxonomic and functional p < 0.001) and insects (taxonomic p = 0.001; functional p = 0.033). We further revealed that threshold responses of functional composition were more geographically consistent than those of taxonomic composition to both urban and agricultural land use change. Traits contributing the most to overall functional composition change differed along urban and agricultural land gradients, and conformed to predicted ecological mechanisms underpinning community change. This study points to reliable early-warning thresholds that accurately forecast compositional shifts in riverine communities to land use conversion, and highlight the importance of considering trait-based indicators of community change to inform large scale land use management strategies and policies. This article is protected by copyright. All rights reserved.

Spatial Variations in Aquatic Insect Community Structure in the Winam Gulf of Lake Victoria, Kenya

Background. Aquatic insect community structure is dynamic due to threats by anthropogenic activities coupled with changing climatic conditions. The insect’s survival is dependent on the substrate, water quality, and environmental effects. The changes in water quality influence their distribution and abundance and are reflected in spatial and temporal trends. This study sought to document the effects of spatial variation on aquatic insects in Winam Gulf of Lake Victoria, Kenya. Materials and Methods. Systematic random design was used in sampling, and water quality parameters were assessed. Insects were sampled by profundal lake procedure, pooled, sorted, and identified based on the morphological approach and diversity indices analyzed. The relationship between insects and water quality was established. Results. Statistical homogeneity in water quality parameters was documented with the exception of nitrates, nitrites, soluble reactive phosphorus, ammonium, and silicates, which displayed significant variation at p &lt; 0.05 . A total of 383 individual insects representing 19 species, 19 genera, 16 families, and six orders were obtained from Winam Gulf. Hemiptera, Ephemeroptera, and Diptera were the most predominant orders, respectively. Chironomus spp. and Ablebesmyia spp. were representatives of the Chironomidae family. Species distribution and water quality were determined using cluster analysis (CA) and conical correspondence analysis (CCA). Conclusion. The findings of this study demonstrated that spatial variations were associated with change in water quality and had a corresponding influence on insect community structure.

Aquatic Insect Communities Remain Impaired Following Large-Scale River Restoration

Aquatic Insect Communities Remain Impaired Following Large-Scale River Restoration

Direct PCR meets high-throughput sequencing – metabarcoding of chironomid communities without DNA extraction

Aquatic emergent insect communities form an important link between aquatic and terrestrial ecosystems, yet studying them is costly and time-consuming as they are usually diverse and superabundant. Metabarcoding is a valuable tool to investigate arthropod community compositions, however high-throughput applications, such as for biomonitoring, require cost-effective and user-friendly procedures. To investigate if the time-consuming and labour-intensive DNA extraction step can be omitted in metabarcoding, we studied the difference in detection rates and individual read abundance using standard DNA extraction versus direct PCR protocols. Metabarcoding with and without DNA extraction was performed with artificially created communities of known composition as well as on natural communities both of the dipteran family Chironomidae to compare detection rates, individual read abundances and presence-absence community composition. We found that the novel approach of direct PCR metabarcoding presented here did not alter detection rates and had a minor effect on individual read abundances in artificially created communities. Furthermore, presence-absence community compositions of natural chironomid communities were highly comparable using both approaches. In conclusion, we showed that direct PCR protocols can be applied in chironomid metabarcoding approaches, with possible application for a wider range of arthropod taxa, enabling us to study communities more efficiently in the future.

Diversity and Abundance of Aquatic Insect Fauna in an Urban Freshwater Lake, Hatirjheel, Dhaka, Bangladesh

Freshwater lakes are a crucial component of the urban ecology and offer several direct and indirect advantages to its people. Habitat degradation of native insects has happened because of development activities and unscientific natural resource management. As a consequence, many insects of freshwater lakes are now rare and endangered. A research was conducted to find out the abundance, variety and distribution of aquatic insect fauna in an urban freshwater lake, Hatirjheel, Dhaka during November 2015 to February 2016. A total of 3255 individuals of water insects comprising of 11 species and 31 genera under 20 families belonging 5 orders were recorded. The order Hemiptera contained the highest abundance (38.71%) including 7 families and 12 genera containing 5 species, while Trichoptera had the lowest (6.45%) including 2 families and 2 genera. The dominating species in the lake was Micronecta haliploides. The maximum 19 aquatic insect species were reported in the lake's vegetation-rich section near the Mouchak-Moghbazar flyover (Spot 1), whereas a minimum of 5 species were found near the Modhubagh bridge road (Spot 2). Species diversity index (H′ = 2.74), species richness (SR = 8.54), aquatic insect distribution evenness (J′ = 0.80), community dominance (CD = 46.94%), and Simpson’s index (λ = 0.17) were analyzed in this study to determine the diversity, abundance, distribution and dominance of aquatic insect fauna in this lake. Bangladesh J. Zool. 50(3): 363-372, 2022

Aquatic insects in plateau streams in Southern Brazil: a functional feeding group analysis

Aquatic insects are bioindicators regarding the quality of streams environments. The present study aimed to analyze the community of aquatic insects in streams from the Santa Catarina Plateau, in Brazil. Insects were classified according to their functional trophic structure as gathering-collectors, filtering-collectors, shredders, swallower-predators, perforator-predators and scrapers. Autotrophy and heterotrophy indices were calculated to evaluate the ecological conditions of the sampled streams. Associations between shredders and the riparian vegetation index, filtering-collector index, riverbed stability index, and predator-prey index were performed. The sampled streams demonstrated that the insects inhabiting these environments respond to the strong seasonality observed in the study region, an area located at high altitudes (over 1,200 m a.s.l.) that suffers harsh winters with snow events. This is also reflected in the seasonal heterotrophy and autotrophy index variations noted herein, with higher autotrophy observed during spring and summer. The relationship detected between shredder insects and riparian vegetation indicates that the sampled region may be suffering from deforestation, due to the low contribution of plant matter to the stream waters. However, as many nearby areas are characterized by natural grasslands, it is possible that it is actually an inherent characteristic of the sample area.

Extreme climatic events alter the aquatic insect community in a pristine German stream

As a result of ongoing climate change, extreme climatic events (ECEs) are expected to become more frequent and severe. The high biodiversity of riverine ecosystems is susceptible to ECEs, especially to water temperature (extreme heat and extreme cold) and discharge-related (flood and drought) events. Long time series are needed to unravel the effects of ECEs on ecological communities. Here, we used 20 years (1986–2005) of unusually high-resolution data from a pristine first-order stream in Germany. Daily recordings of species-level identified aquatic insect (Ephemeroptera, Plecoptera, Trichoptera: EPT) emergence, water temperature and discharge data were used to examine the effects of four types of ECEs (extreme heat, extreme cold, flood, and drought events) on insect abundance, common taxonomic diversity metrics, and selected traits after five different time lags (2 weeks, 1, 3, 6, and 12 months). Extreme heat events increased from 1.8 ± 1.9 SE events per year before 2000 to 5.3 ± 1.9 SE events per year after 2000. Water temperature-related ECEs restructured the EPT community in abundance, species richness, and traits (community temperature index: CTI, and dispersal capacity metric: DCM). The strongest effects on the EPT community were found when it was exposed to multiple ECEs and 1 and 3 months after an ECE. The changing frequencies and durations of ECEs, especially the increasing frequency of extreme heat events and the negative cumulative effects of ECEs, paint a worrisome picture for the future of EPT communities in headwater streams. High-resolution, long-term data across sites is needed to further disentangle the effects of different ECE stressors.

Freshwater insect communities in urban environments around the globe: a review of the state of the field

Urbanization is a key stressor of freshwater habitats, possibly contributing to global insect declines. However, scientific understanding of urbanization's effects on aquatic insect communities has largely been based on studies of temperate streams. We reviewed global urban freshwater macroinvertebrate community studies, classifying habitat type, location, urbanization metrics, biodiversity metrics, and focal taxa, drawing from 114 studies in 32 different countries. Our goals were to: (1) investigate the extent of research on urbanization across a variety of freshwater habitats, (2) examine the representation in empirical literature across the globe by comparing cities in different geographic regions, and (3) highlight how study approaches including taxonomic resolution and the inclusion of trait data impact interpretation of these patterns. Most studies were conducted in North America and Europe, but there is growing representation from other continents. Additionally, lentic environments were underrepresented in the literature on community responses to urbanization compared to lotic studies. Therefore, we suggest that lentic habitats should be investigated more thoroughly. We suggest that future empirical studies should incorporate traits of the taxa investigated to better predict how communities respond to urban stressors. The lack of consistent results from the reviewed studies showed that there is no single, predictable effect of urbanization, indicating that future meta-analyses and review papers should consider the potential context-dependency of freshwater insect responses to anthropogenic pressures. Our goal in highlighting understudied environmental and regional contexts is to move toward holistically addressing the ongoing challenges of urban freshwater insect conservation and freshwater ecology research.

Non-target effects of methoprene and larvicidal surface films on invertebrate predators of mosquito larvae.

Mosquito larvicides are used across a variety of aquatic habitats, although when applied they likely affect other aquatic organisms. The removal or impairment of top insect predators via larvicides could be beneficial to mosquitoes by allowing their populations to rebound once pesticide levels dissipate. Our goal was to determine if two larvicide types, growth regulators (IGRs) and surface films (SFs), harm non-target aquatic insect communities, and if these chemicals influence the ability of predatory aquatic insects to regulate mosquitoes. We surveyed aquatic sites before and after IGR and SF-application, then compared changes in insect community structure. Evenness was lower in SF treated habitats, and when analyzing prey/controphic taxa only, evenness and diversity changed in untreated reference areas, suggesting that differences measured were due to other environmental factors, not larvicide presence. A field experiment was then conducted by exposing specific predatory aquatic insects to varying doses of IGRs and SFs and then placing them in mesocosms containing mosquito larvae. Surface films were directly lethal to adult dytiscids at recommended and high concentrations. Although we found no significant differences in mosquito emergence among all treatment levels, there was a trend of negative controls (no predator mesocosms) and SF-treated predators allowing the most mosquitoes to emerge compared to positive controls (predators not exposed to larvicides) and IGR-treated predators. Thus, these larvicides may have minimal effects on mosquito larvae predators, but the direct effects of surface films on insects that interact with the water's surface require further investigation.

Spatio-temporal distribution of aquatic insects and functional feeding groups in different stretches of River Jatinga, south Assam, India

The present study investigated aquatic insect community of River Jatinga, one of the major north bank tributaries of Barak River, North east India. The objectives of this study were to find out spatial and seasonal distribution of aquatic insects and their functional feeding groups (FFG). Aquatic insects were collected seasonally in five different stretches of the river. Parameters like taxa richness, insect density, diversity indices, FFG%, riverbed sediment texture and particles sizes were determined. Total 37 and 38 numbers of aquatic insect families belonging to eight orders were recorded in the first and second year, respectively. In both years, the upstream sites with rocky substratum showed higher taxa richness (15) in pre monsoon and density (47.33 ± 8.5) in winter season than that of downstream sites with sandy substratum. The size of particles gradually decreased from upstream sites to downstream sites. Boulders, cobbles, pebbles and granules mostly dominated the upstream sites (US1 and US2) while boulders and cobbles were totally absent in both downstream sites. Trichoptera, Hemiptera, Ephemeroptera and Diptera were the major orders and the major families were Psephenidae, Elmidae, Baetidae, Hydropsychidae, Leptophlebiidae, Gerridae and Simuliidae. The number of FFG types was higher in upstream sites than that of midstream and downstream sites in both years indicating preference for heterogenous habitat. The predators being mostly tolerant occurred across sites and seasons while sensitive groups like scrapers, shredders were found only in the upstream sites. Predators showed highest percentage (97.56) followed by piercers-herbivores, predators/scrapers (83.33). Canonical correspondence analysis revealed distinctive association between the insect community and particle sizes.