Aquatic Insect Communities Research Articles

水田内の環境と周辺の景観が水生昆虫群集（コウチュウ目・カメムシ目） に与える影響

水田内の環境と周辺の景観が水生昆虫群集（コウチュウ目・カメムシ目） に与える影響

Disentangling how climate change can affect an aquatic food web by combining multiple experimental approaches.

Predicting the biological effects of climate change presents major challenges due to the interplay of potential biotic and abiotic mechanisms. Climate change can create unexpected outcomes by altering species interactions, and uncertainty over the ability of species to develop in situ tolerance or track environmental change further hampers meaningful predictions. As multiple climatic variables shift in concert, their potential interactions further complicate ecosystem responses. Despite awareness of these complexities, we still lack controlled experiments that manipulate multiple climatic stressors, species interactions, and prior exposure of species to future climatic conditions. Particularly studies that address how changes in water availability interact with other climatic stressors to affect aquatic ecosystems are still rare. Using aquatic insect communities of Neotropical tank bromeliads, we combined controlled manipulations of drought length and species interactions with a space-for-time transplant (lower elevations represent future climate) and a common garden approach. Manipulating drought length and experiment elevation revealed that adverse effects of drought were amplified at the warmer location, highlighting the potential of climatic stressors to synergistically affect communities. Manipulating the presence of omnivorous tipulid larvae showed that negative interactions from tipulids, presumably from predation, arose under drought, and were stronger at the warmer location, stressing the importance of species interactions in mediating community responses to climate change. The common garden treatments revealed that prior community exposure to potential future climatic conditions did not affect the outcome. In this powerful experiment, we demonstrated how complexities arise from the interplay of biotic and abiotic mechanisms of climate change. We stress that single species can steer ecological outcomes, and suggest that focusing on such disproportionately influential species may improve attempts at making meaningful predictions of climate change impacts on food webs.

Assessing community functional attributes during substrate colonization: a field experiment using stream insects

Initial colonists of empty habitats tend to differ from those arriving later in terms of species identity and traits. We evaluated the dynamics of the functional attributes in aquatic insect communities during a colonization experiment under natural conditions. We tested whether the late stages of colonization show higher functional richness, diversity and specialization than early successional stages. We used 60 artificial slate samplers that were removed after 1, 3, 5, 10, 15 and 30 days of colonization. We considered five traits (with a total of 17 trait categories): feeding habits, dispersal medium, body size, body shape and locomotion. With these traits, we computed a global specialization index at the community level. Large shredders with a cylindrical body shape and fly dispersal while flying were prominent in late colonization. In contrast, early colonists tended to have flattened body and to disperse through water. Functional diversity and functional richness significantly increased in late colonization, resulting in a more specialized community. Our results suggest that any interference during the processes involved in stream insect colonization can be reflected in the community through the decrease or even lack of functional attributes.

Aquatic insect communities in small stream in the south of Brazil.

Pollution of rivers and streams, by anthropic action, is characterized as an environmental, social, and sanitary problem. Factors such as the association between the marginal vegetation, the distribution of the substrates in the riverbed, and the availability of allochthonous organic matter influence the distribution and composition of the aquatic entomofauna. The objective of this study was to analyze the structure of aquatic insect communities in a pasture stream in northern Paraná, southern Brazil, with emphasis on the groups of indicators of good water quality, thus inferring the conditions of its preservation. Samples were collected from July to October in three parts of the stream (P1, P2, and P3), where the insect faune was collected with the aid of a sieve in the foliage substrate and washing of rocks and decomposing pieces of wood. A total of 1323 individuals were collected, being Chironomidae (Diptera) the most abundant taxon. The analysis of the biotic indices (EPT/Chironomidae, IBF, BMWP, and BMWP/ASPT) and diversity indicated better preservation conditions at points P1 and P3 where the riparian forest was well preserved, with less exposure to the stream bed. In P2, the entomofauna presented less diversity and the biotic indexes indicated loss of water quality, showing the impacts of changes in the marginal vegetation of this section. In a generally preserved aquatic environment, small changes in its vegetation are sufficient to cause an imbalance in the aquatic insect community, showing the efficiency of these organisms as bio-indicators and the sensitivity of biotic indexes.

Neonicotinoids and other agricultural stressors collectively modify aquatic insect communities

Threats to wetland water quality and aquatic insect secondary production in agricultural landscapes are multifaceted and are known to vary spatially and temporally. We designed this study with the aim to disentangle the effects of multiple stressors on emerging aquatic insects from wetlands impacted by intensive agricultural practices and receiving runoff from neonicotinoid-treated canola. A total of 22 semi-permanent wetlands were monitored over two growing seasons (11 different wetlands per year) in central Saskatchewan, Canada. Over the two sampling years, dipterans from the families Chironomidae (60–67%), Muscidae (13–15%) and Ceratopogonidae (7–13%) made up the majority of emergent taxa, representing 80–95% of the total emergence. Multivariate ordination analyses of eight water quality and nine wetland habitat variables revealed that neonicotinoid concentration, turbidity, vegetation disturbance, and continuity of a vegetative grass buffer zone were significant factors influencing the aquatic insect taxa composition. Generalized linear mixed effects models indicated that total insect emergence over time was significantly predicted by neonicotinoid concentrations (imidacloprid toxic equivalency, TEQ) and vegetation disturbance. Higher neonicotinoid concentrations negatively affected insect emergence over time, whereas vegetation disturbance increased total emergence, likely due to the abundance of disturbance-tolerant taxa. Overall, we observed community-level responses driven by multiple indicators of wetland degradation (insecticides, turbidity, and vegetation disturbance). Collectively, these multivariate field data provide an in-depth understanding of how agricultural management practices, including neonicotinoid use, interact to shape wetland aquatic insect communities.

Community responses of aquatic insects in paddy mesocosms to repeated exposures of the neonicotinoids imidacloprid and dinotefuran

Pesticides are one of major threats to wetland environments and their communities, and thus the information about ecological impact assessment of agro-chemicals on ecosystems is essential for future effective pesticides management. Here, effects of the yearly application of two neonicotinoids, imidacloprid and dinotefuran on aquatic insect communities of experimental rice fields were assessed during two years of monitoring. Both neonicotinoid-treated fields and controls were monitored biweekly throughout the 5-month experimental period until harvest (late October) in each year. Maximum concentrations of imidacloprid (157.5 μg/l in 2014 and 138.0 μg/l in 2015) and dinotefuran (10.54 μg/l in 2014 and 54.05 μg/l in 2015) in water were relatively similar in both years, but maximum residues of imidacloprid (245.45 μg/kg) and dinotefuran (419.5 μg/kg) in the sediment in the second-year were 18 and 175 times higher than in the first year, respectively, with great variability of concentrations among sampling dates. In addition, remaining soil residues of both neonicotinoids were approximately 1 μg/kg (ppb) at the start of the second-year. A total of 6265 individuals of 18 aquatic species belonging to 7 orders were collected. No differences in the number of species between controls and the two neonicotinoids-treated paddies were found between years. However, clear differences in community structures of aquatic insects among the imidacloprid- and dinotefuran-treated mesocosms, and controls and between years were shown by PRC analysis. In particular, imidacloprid likely decreased Crocothemisia servilia mariannae nymphs, Chironominae spp. larvae, and Aedes albopictus larvae, whereas dinotefuran tended to decrease Guignotus japonicus, Orthetrum albistylum speciosum nymphs, and Tubiificidae spp. In addition, long-living species of Coleoptera and Odonata were most sensitive to both neonicotinoids. Changes in composition of feeding functional groups (FFGs) of aquatic insects were more prominent in the first year and became subtler in the second year. One of the possibilities of this phenomenon may be functional redundancy in which species that had low sensitivity to imidacloprid and dinotefuran replaced the vacant niche caused by decreases of other species with high susceptibility within the same feeding functions, although further studies are needed to verify this explanation. Thus, feeding functional traits can be a good indicator for evaluation of changes in ecosystem processes under pesticides exposures. Consequently, the current study emphasized that more realistic prediction of community properties after the repeated application of agrochemicals in successive years should consider for 1) long-term population monitoring, 2) cumulative effects at least over the years, and 3) species' functional traits.

Effects of Wood Density on Aquatic Insect Communities in a Cuban Montane Rainforest Stream.

We tested whether hardness or different wood carbon densities, considered as the concentration of carbon structural compounds, influence functional feeding groups and species richness of aquatic insects in a tropical stream. We expected that harder woods would harbor aquatic insect communities with species richness and functional food group profile different from softwoods. We also expected that collector-gatherers and collector-filterers will be more abundant in softwood because harder woods are less substrate suitable for biofilm production. Aquatic insects associated with the following plants were analyzed: Gomidesia lindeniana with high-density, Psychotria grandis with medium-density, and Meriania leucantha with low-density wood. Diptera and Ephemeroptera were the most abundant groups sampled in the woods. Psychotria grandis shows higher concentrations of lignin, cellulose, and hemicellulose, followed by G. lindeniana and M. leucantha. Breakdown rates are different among plant species with M. leucantha having four times highest breakdown rates and on average three more species in the species richness value. We did not find significant differences in the composition of insect species associated with the plants. We found evidence that the richness and functional organization of aquatic insect communities were mostly related to the breakdown rates and lignin amount of the woods. Plants that decompose faster on average have three more species and two more insect functional groups. Our findings suggest that the loss of high carbon density trees in tropical forests can affect aquatic biodiversity.

Aquatic–terrestrial linkages provide novel opportunities for freshwater ecologists to engage stakeholders and inform riparian management

AbstractStudies of aquatic–terrestrial ecosystem linkages explore the mechanisms by which components of one ecosystem, such as the aquatic insect community in a stream, directly affect components o...

Corrigendum to: Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems.

Aquatic Insects and Water Quality Study at Kimanis River, Crocker Range National Park, Sabah, Malaysia

A survey on the aquatic insect communities was conducted in Kimanis River, Ulu Kimanis, Crocker Range Park (CRP), Sabah with the objectives to study (i) the composition of stream insect communities, (ii) stream water quality and (iii) the relationships between aquatic insects and freshwater quality parameters in Kimanis River, Ulu Kimanis, CRP. The sampling was carried out using surber net in October 2015 and January 2016. A total of 1,801 individuals from nine orders of 28 families were collected from Kimanis River. Trichopterans fauna was found to be the prominent taxa in this study. Shannon-Wiener Index of upstream strata was recorded slightly higher than downstream strata with H’= 1.97 and H’= 1.85 respectively. Water integrity of Kimanis River could be considered as excellent with minimal pollution. Both water quality parameters and biotic indices indicated that the aquatic insect population was affected by the water quality in their surroundings. This proved the use of aquatic insect communities as bioindicator for rapid assessment of water quality in CRP.

Aquatic Insect Community as Indicator of Water Quality Assessment in Situ Gede System, Bogor, Indonesia

Aquatic insects have important role in food web and can be used as bio-indicators in aquatic ecosystems. Each aquatic insect has different tolerance value to environment condition in which only few species can survive in polluted ecosystems. Thus, lakes condition can be evaluated by using aquatic insects. One of purpose of this study is to assess the water quality in four situ using aquatic insects community as biotic index. Insects and abiotic data were sampled once a month for five months (January, February, March, June, and July 2016) in Situ Gede Systems including Situ Gede (SG), Situ Panjang (SP) and Situ Burung (SB), compare with Situ LSI (SL) as an excluding the system. Twelve sampling points of littoral zone were selected in each situ. Insects were captured by filtering fifty-liter water of situ using net with 50 µm mesh size. Abiotic factors such as pH, temperature, DO, and turbidity of water measured at each situ. During the study period, aquatic insect community was represented by a total 598 individual from 14 families. Corixidae and Notonectidae were the most dominant family in all situ. Based on Hilsenhoff Biotic Index (HBI), all situ were fairly contaminated by organic compound.

Changes in Aquatic Insect Community Structure in Wonju Stream based on a Comparison of Previous Studies

Changes in Aquatic Insect Community Structure in Wonju Stream based on a Comparison of Previous Studies

Neonicotinoid insecticide mixtures: Evaluation of laboratory-based toxicity predictions under semi-controlled field conditions

Neonicotinoid insecticide mixtures are frequently detected in aquatic environments in agricultural regions. Recent laboratory studies have indicated that neonicotinoid mixtures can elicit greater-than-additive toxicity in sensitive aquatic insects (e.g. Chironomus dilutus). However, this has yet to be validated under field conditions. In this study, we compared the chronic (28- and 56-day) toxicity of three neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) and their mixtures to natural aquatic insect communities. Using experimental in-situ enclosures (limnocorrals), we exposed wetland insects to single-compounds and binary mixtures at equitoxic concentrations (1 toxic unit under the principle of Concentration Addition). We assessed the composition of all emerged insect taxa and the cumulative Chironomidae emergence and biomass over time. In treated limnocorrals, there were subtle shifts in community composition, with greater mean proportions of emergent Trichoptera and Odonata. Cumulative emergence and biomass increased over time and there was a significant interaction between time and treatment. At 28 days, cumulative Chironomidae emergence and biomass were not significantly different between neonicotinoid treatments and controls. However, cumulative emergence in the imidacloprid, clothianidin, and clothianidin-thiamethoxam treatments were 42%, 20%, and 44% lower than predicted from applied doses. At 56 days, effects on cumulative emergence and biomass were significant for imidacloprid, clothianidin, and the clothianidin-thiamethoxam mixture. Contrary to laboratory predictions, mixtures were not more toxic than single compounds under semi-controlled field settings. Furthermore, only clothianidin significantly shifted sex-ratios towards female-dominated populations. Results showed that the responses of natural Chironomidae populations to neonicotinoids and their mixtures cannot be adequately predicted from laboratory-derived single-species models, and although occasional overdosing may have influenced the magnitude of effects, reductions in Chironomidae emergence and biomass can occur at average neonicotinoid concentrations below some current water quality guidelines. Therefore, neonicotinoid guidelines should be revised to ensure that Chironomidae and other sensitive aquatic insects inhabiting agricultural wetlands are adequately protected.

Insectos acuáticos asociados a raíces de Eichhornia crassipes (MART) Solms en ciénagas del río Atrato, Chocó – Colombia

Las macrófitas acuáticas desempeñan un importante rol en los sistemas lénticos, al constituir un hábitat particular para varios grupos de insectos acuáticos y jugar un papel importante en la estructuración de sus comunidades. El objetivo de este estudio fue caracterizar la comunidad de insectos acuáticos asociados a Eichhornia crassipes (Mart) Solms en cinco ciénagas de la cuenca media y baja del río Atrato, Chocó-Colombia. Durante dos meses se hicieron colectas de insectos acuáticos, utilizando un cuadrante de un m2, dotado de una malla de 0,5 mm, con tres replicas por ciénaga. Simultáneamente se midieron algunas variables físicas, químicas e hidrológicas (oxígeno disuelto, pH, temperatura del agua, Conductividad eléctrica, alcalinidad, sólidos totales disueltos, transparencia y profundidad). La comunidad estuvo compuesta por 6 órdenes, 18 familias y 24 géneros. El orden más abundante fue Coleoptera (39,81%), sobresaliendo la familia Gyrinidae con el género Hydrocanthus; mientras que la mayor riqueza taxonómica fue para los dípteros con 7 géneros, entre los que destaca Ablabesmyia. El índice de diversidad presentó un promedio de 1,17 bits/ind ± 0,47, mientras que el promedio de la dominancia fue de 0,54 ± 0,20. Los grupos funcionales de mayor abundancia fueron los predadores y colectores que representaron el 99,04% de los individuos, predominando Hydrocanthus (Gyrinidae) y Callibaetis (Baetidae) respectivamente. Las variables fisicoquímicas no mostraron diferencias significativas entre muestreos y existieron fuertes asociaciones entre la entomofauna acuática y las variables abióticas analizadas.

Impacts of Small Impoundments On An Intermittent Headwater Stream Community

The impacts of small impoundments on headwater streams have received little attention despite their potential to have local and broad-scale ecological impacts. These impoundments might alter stream hydrology, geomorphology, and facilitate the spread of invasive species. Given that prairie stream communities have adapted to highly variable conditions, they might resist disturbances associated with small impoundments. To test the resistance of aquatic communities to the disturbances associated with small impoundments, we surveyed intermittent headwater prairie streams in both unimpounded and impounded watersheds. We observed greater fish density and species richness in unimpounded watersheds and two species occupying a greater proportion of sites in unimpounded than impounded watersheds. In contrast to fish communities, we observed no difference in crayfish density or the community structure and biomass of aquatic insect and snail communities between unimpounded and impounded watersheds. Increased sensitivity to disturbances associated with small impoundments by fishes might be attributed to their limited dispersal capabilities.

Insectos acuáticos asociados a Eichhornia azurea (Schwartz) Kunth en ciénagas del río Atrato, Chocó - Colombia

El objetivo de este estudio fue caracterizar la comunidad de insectos acuáticos asociados a Eichhornia azurea (Schwartz) Kunth en cuatro ciénagas de la cuenca media y baja del río Atrato (Chocó-Colombia) durante los periodos de aguas altas y bajas; igualmente se evaluó la influencia de las variables ambientales y fisicoquímicas sobre esta comunidad. Durante dos meses se hicieron colectas de insectos acuáticos asociados a las raíces de E. azurea, utilizando un cuadrante de un m2, dotado de una malla de 0,5 mm, con tres replicas por ciénaga y simultáneamente se midieron algunas variables físicas y químicas del agua. La comunidad estuvo compuesta por 6 órdenes, 21 familias y 28 géneros. El mayor número de organismos (55,39%) y de taxones (23) se registró en el periodo de aguas bajas. Los órdenes más abundantes fueron Ephemeroptera (37,55%) y Coleoptera (26,77%), sobresaliendo las familias Baetidae y Noteridae respectivamente; mientras que la mayor riqueza taxonómica fue para coleópteros, dípteros y hemípteros. No se presentaron diferencias significativas en la diversidad y dominancia entre periodos hidrológicos (p>0,05), pero si en la riqueza específica (p<0,05). Los grupos funcionales de mayor abundancia fueron predadores (54,81%) y colectores (43,70%). Las variables fisicoquímicas hídricas no mostraron diferencias significativas entre periodos hidrológicos y se presentaron asociaciones entre la entomofauna acuática y las variables abióticas analizadas, principalmente con el oxígeno disuelto, la conductividad y los sólidos totales disueltos.

Cave benthic invertebrates in south-eastern Brazil: are there 'key' factors structuring such communities?

The aim of this study was to determine the effects of microhabitat traits related to water quality and physical features of stream channels (substrate, channel morphology and hydraulic characteristics) on the richness and structure of the aquatic insect assemblage in cave streams. Sampling was conducted in three subterranean streams in Brazil. Aquatic insect richness was significantly and positively related to water depth and the presence of shelters for invertebrates. These shelters are directly related to channel heterogeneity, a factor that determined the surface area of habitats suitable for colonisation, refuges and the amount and variety of nutrients in streams where resources are extremely limited. Furthermore, analyses of community composition revealed that aquatic insect assemblages in each cave were structured by distinct factors (including physicochemical characteristics of the water or hydraulic features of the channel). Together, these findings highlight that different factors are responsible for structuring the assemblages in each cave, which may reflect their local variability, and that silting of cave streams would likely have deleterious effects on aquatic insect communities through reductions in overall habitat heterogeneity.

Check dams exacerbate the effects of high flow on aquatic insect communities in tropical stream of northern Thailand

Check dams exacerbate the effects of high flow on aquatic insect communities in tropical stream of northern Thailand

Composition and distribution of aquatic insect community of a non-stocked pond of Banco National Park (Côte d’Ivoire, Western Africa).

Composition and distribution of aquatic insect community of a non-stocked pond of Banco National Park (Côte d’Ivoire, Western Africa).