Aquatic Insect Assemblages Research Articles

Beta diversity of aquatic macroinvertebrate assemblages associated with leaf patches in neotropical montane streams.

Over 70% of the total channel length in all river basins is formed by low order streams, many of which originate on mountaintops. Headwater streams play fundamental roles in processing and transporting terrestrial and aquatic organic matter, often harboring high biodiversity in bottom leaf patches deposited from riparian vegetation. The objective of this study was to assess the variation in taxonomic composition (measured by beta diversity of aquatic macroinvertebrates) among stream sites located in the Espinhaço Meridional Mountain Range, part of a UNESCO Biosphere Reserve in eastern Brazil. We tested two hypotheses. (a) Taxa turnover is the main reason for differences in aquatic insect assemblages within stream sites; we predicted that turnover would be higher than nestedness in all stream sites. (b) Stream site altitude and catchment elevation range are the main explanatory variables for the differences in beta diversity; we predicted that local stream site variables would account for only minor amounts of variation. In both dry and wet seasons, we sampled twice in two habitat types (five leaf patches in pools and five in riffles) in each of nine stream sites distributed in three different river basins. We computed average pairwise beta diversity among sampling stations and seasons in each stream site by using Jaccard and Bray–Curtis indices, and calculated the percentages of diversity resulting from turnover and nestedness. Finally, we tested the degree that local‐ or catchment‐level predictor variables explained beta diversity. We found that turnover was the main component of beta diversity and that both dissolved oxygen and elevation range best explained Bray–Curtis beta diversity. These results reinforce the importance of leaf patches in montane (sky islands) Neotropical savanna streams as biodiversity hotbeds for macroinvertebrates, and that both local and landscape variables explained beta diversity.

The effect of artisanal gold mining on aquatic insect communities: a case study in Costa Rica

Among the anthropogenic disturbances that affect rivers, artisanal and small-scale gold mining (ASGM) has recently generated great concern regarding the deterioration of aquatic ecosystems. This study aimed to evaluate the impact of ASGM on the assemblages of aquatic insects. For this, aquatic insects were sampled from two actively mined streams in the Osa Peninsula in Costa Rica. ASGM produces significant changes in the richness, abundance and assemblage’s composition of aquatic insects. These changes, however, are mitigated a few meters downstream, after encountering a seemingly undisturbed tributary, for which the stream seems to keep its stability through resilience. For ASGM activities that have low intensities of extraction and don’t use pollutant chemicals for amalgamation, keeping a low intensity of the activity and a considerable distance between goldmining sites could be an option for a more sustainable development of this activity, since it allows biodiversity to be partially restored.

Value of artificial ponds for aquatic insects in drought-prone southern Africa: a review

Artificial ponds assure continuous societal water supply, especially during droughts. Obligate aquatic and amphibiotic insects readily inhabit novel water bodies, as many possess mobility traits for opportunistic colonization. We review here the value of artificial ponds ( 2 ha) for local aquatic insect diversity in mostly dry and drought-prone southern Africa. We compare these ponds to natural pools, wetlands, and stream deposition pools. The region has a highly varied topography and physiographical zones. Flat, arid areas largely support widespread insect generalists, while the mountainous orographic zones support an additional rich fauna of localized endemics. However, the many ponds (> 0.5 million) have greatly changed the local distribution patterns of surface freshwater across the region, increasing the area of occupancy for many aquatic insect species, especially dragonflies. We focus on the extent to which aquatic insect assemblages have benefitted from new ponds and reservoirs. We conclude that these novel ecosystems benefit almost all lentic aquatic insect species, while also enabling population resilience during droughts. However, while these benefits are substantial, these ponds are not a substitute for natural still waters, which are still required to maintain all indigenous lentic aquatic insect diversity.

Unveiling patterns of taxonomic and functional diversities of stream insects across four spatial scales in the neotropical savanna

The drivers of dissimilarity in biological communities among habitats and the mechanisms that modulate the distribution of functional diversity in streams are still important gaps in ecological knowledge. This study was designed to assess how the taxonomic and functional composition of Cerrado stream insect assemblages are distributed among multiple spatial scales (i.e., habitat, stream sites and hydrological units). To do so we used a hierarchical series of four diversity components: stream transect (α), among transects (β1), among stream sites (β2), and among hydrological units (β3). Our aim was to identify the spatial scales at which variation in aquatic insect assemblage structure was greatest and whether turnover or nestedness mainly explain the patterns of β-diversity. We found that β-diversity among streams (β2) is highest and contributes most to total richness (γ-diversity) of aquatic insects in Cerrado streams as opposed to dissimilarities among habitats or among hydrological units. Moreover, β-diversity among transects had the lowest contribution to total insect richness (γ-diversity). The turnover component of taxonomic β-diversity was high for all spatial scales, but highest at stream scale. Conversely, for functional β-diversity, nestedness was the main component at stream scale. Understanding how biodiversity changes from local to regional scales is a first step towards understanding the variation in species and trait composition across space. Our results emphasize the importance of conserving Cerrado headwater streams because each stream harbors different taxa and human disturbance of any stream will result in loss of diversity and ecosystem functions.

Energetics as a lens to understanding aquatic insect's responses to changing temperature, dissolved oxygen and salinity regimes.

Assemblages of aquatic insects are structured by multiple biotic and abiotic conditions, including temperature, salinity and oxygen. Here we highlight recent developments in our understanding of how high temperatures, elevated salinities and low oxygen levels affect physiological processes, responses at the organismal level, and impacts on species interaction and community assembly. As aquatic insects may be exposed to multiple stressors, we review their sensitivity to interactive effects of multiple stressors. While each of these stressors may operate via different physiological mechanisms, they all influence the overall energy budget as well as the allocation of energy to competing functions such as homeostatic maintenance, growth, development and reproduction. As such, there is potential for interaction whereby one stressor may exacerbate the effect of another stressor. Integrating research on these stressors can provide a powerful approach for delineating the sensitivity of aquatic insects to multiple stressors and developing sound management practices.

Aquatic insect assemblages in four urban lakes of Bogor, West Java, Indonesia

Abstract. Wakhid, Rauf A, Krisanti M, Sumertajaya IM, Maryana N. 2020. Aquatic insect assemblages in four urban lakes of Bogor, West Java, Indonesia. Biodiversitas 21: 3047-3056. Urban lakes represent important habitats for some freshwater organisms and support a high diversity of insect fauna. Study was conducted with the objectives to determine and compare aquatic insect assemblages in four urban lakes of Bogor, West Java, Indonesia. Insects were collected in the littoral zone using D-net at a certain interval along the perimeter of each lake. Sampling was carried out monthly during March, April, and May 2017. A total of 6,686 individuals representing 82 species/morphospecies, 28 families, and seven orders were recorded. Estimation of species richness by Chao1 suggested that sampling completeness for Situ Babakan, Situ Burung, Situ Gede, and Situ Tonjong were 88.71%, 75.86%, 82.17%, and 95.23%, respectively. Rarefaction curves indicated that more sampling would record a higher species richness. The least species richness and diversity of aquatic insect assemblages occurred in Situ Babakan characterized by high organic pollution due to fish farming. Canonical correspondence analysis showed that certain environmental factors were related to some species. Chironomus sp. (Diptera: Chironomidae), Micronecta ludibunda (Hemiptera: Micronectidae), and Anisops bouvieri (Hemiptera: Notonectidae) were associated with organically polluted water. Odonates such as Pseudagrion sp.1 (Coenagrionidae), Rhinocypha sp. (Chlorocyphidae), Acisoma panorpoides, Orthetrum sabina (Libellulidae), and Crocothemis servilia (Libellulidae) were associated with conditions of a high density of macrophytes. Our study provides baseline data for future monitoring and conservation management of these lakes.

How Habitat Filtering Can Affect Taxonomic and Functional Composition of Aquatic Insect Communities in Small Amazonian Streams.

Responses in taxonomic and functional composition of communities were analysed in small Amazonian streams at the small and large scale (habitat patches, river segment scale, and catchment scale). We hypothesised that similar responses in community structure to local environmental factors were a correlation between taxonomic and functional composition. To evaluate the response of taxonomic composition to environmental variables, redundancy analysis (RDA) and RLQ analysis were performed to investigate the response of community abundance (L) as a function of the environment (R) and traits (Q). The fourth-corner analysis was applied to summarize specific interactions between environmental variables and traits. Then, community taxonomic composition was associated with models at multiple scales of habitat (i.e. riparian/channel, substrates, and water variables). Likewise, the fourth-corner tests and RLQ axes showed associations between trait composition and environmental variables related to variables, such as riparian cover and channel morphology followed by variation in substrate size and composition. Unexpectedly, these results did not show specific associations between unique environmental variables and traits. At last, results showed that local conditions of stream habitat regulated community structure and functional composition of aquatic insects. Thus, these findings indicate that the local environmental filtering appears to be strongly associated with selected species traits adapted to occur in a range of habitat conditions. Despite the low number of analysed streams, these results provide important information for understanding the simultaneous variation in functional trait composition and community composition of aquatic insect assemblages.

First fossil true water bugs (Heteroptera, Nepomorpha) from Upper Jurassic strata of North America (Morrison Formation, southeastern Utah)

ABSTRACT The first fossil hemipteran from the Late Jurassic of North America, Morrisonnepa jurassica n. gen. et n. sp., is reported and described from the Morrison Formation, Jurassic Salad Bar locality, San Juan County, Utah, USA. The new specimen is characterised and illustrated, showing morphological characters similar to nepomorphs such as forewing well-developed and folded flat on the abdomen, oval abdomen shape, and the presence of a short pair of appendages. The taxonomic allocation close to members of the Nepomorpha is discussed. Morrisonnepa jurassica n. gen. et n. sp. was collected with abundant plants, spinicaudatan carapaces, and a small amphibian from a finely laminated shale that overlies a coarser plant debris bed, supporting the presence of a possible oxbow lake or pond, environments developed within the greater ecosystem of the Morrison Formation during the Late Jurassic. In this context, we analyse the taphonomic and palaeoecological implications of the presence of aquatic insects. Besides providing morphological information on Jurassic nepomorphs, the new fossil helps illustrate how the aquatic insect assemblage was integrated during the Jurassic in North America.

Fluctuating pond water levels and aquatic insect persistence in a drought-prone Mediterranean-type climate

In dry areas, natural and artificial ponds experience frequent water level fluctuation, affecting conditions for some aquatic and amphibiotic taxa. Water beetles, bugs, and dragonflies make up much of pond diversity, and are responsive to changes in environmental conditions. Using a drought-prone pondscape within the Greater Cape Floristic Region biodiversity hotspot, we determine (1) the relative extent to which species richness, abundance, and composition are affected by pond water level fluctuation, (2) the effects of environmental variables and vegetation characteristics relative to fluctuating water levels, and (3) make recommendations to improve pondscape conservation. We found that the degree of fluctuation had a significant effect on beetle species richness, but had no significant effect on the other focal taxa. Water temperature, pH, and conductivity, and vegetation cover and composition were drivers of aquatic insect species richness, abundances, and assemblage structures. Habitat heterogeneity supported rich aquatic insect assemblages. We recommend that a range of ponds with various degrees of water level fluctuation should be maintained, along with naturally diverse marginal vegetation. Such a dynamic pondscape can contribute greatly towards maintenance of local and regional aquatic insect diversity in drought-prone regions and should be considered as a main focus in conservation efforts.

Nestedness of insect assemblages in agriculture-impacted Atlantic forest streams

Agricultural land use causes habitats fragmentation and riparian vegetation removal, driving variability in the composition of aquatic insect assemblage in streams. We explored the effect of agriculture on the beta diversity of insect assemblages of Ephemeroptera, Plecoptera and Trichoptera (EPT) in Atlantic forest streams. We measured water physical and chemical variables and quantified the land cover of 10 stream catchments to determine the environmental integrity of the streams. The percentage of vegetation range was ∼6% to ∼47%, and agricultural land use range was ∼24% to ∼88%. We collected a total of 2632 individuals distributed in 30 genera. Trichoptera was the most abundant order (57%), followed by Ephemeroptera (41%) and Plecoptera (2%). The abundance was influenced by the higher agriculture practices in the streams adjacent areas. On the other hand, the oxygenated waters and higher percentages of riparian vegetation influenced the EPT rarefied richness. The beta diversity of EPT assemblages was structured by nestedness due to the influence agricultural activities. The variation in the agricultural intensity that occurs in the streams generated more intense limnological variability, which caused the nestedness of EPT insects as well as the reduction of taxonomic richness. Thus, the streams with low environmental integrity had EPT assemblages nested in streams of high environmental integrity.

The role of spatial and environmental variables in shaping aquatic insect assemblages in two protected areas in the transition area between Cerrado and Amazônia

Abstract: The distribution of aquatic insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) can be influenced by factors such as water quality, habitat integrity and biogeography. The present study evaluated the structure of EPT assemblages in streams in the Cerrado, a global biodiversity hotspot. Samples were collected from 20 streams in two protected areas: Parque Estadual do Mirador (10 streams) and Parque Nacional da Chapada das Mesas (10 streams). A total of 1987 specimens were collected, representing 46 taxa of EPT. The two study areas did not differ significantly in taxonomic richness of EPT genera (t = -1.119, p = 0.279) and abundance of individuals (t = 0.268, p = 0.791) but did differ in genus composition (Pseudo-F = 2.088, R2 = 0.103, p = 0.015) and environmental variables (Pseudo-F = 2,282, R2 = 0.112, p = 0.014). None of the tested environmental variables were correlated with the community but a spatial filter captured an effect of the spatial distribution of streams. The region of the study is located in MATOPIBA, which is the last agricultural frontier of the Cerrado. Therefore, it is important that there is police and monitoring so that the “Parque Estadual do Mirador” and the “Parque Nacional da Chapada das Mesas” continue to play their role in conserving biodiversity in the future.

Aquatic insect diversity in streams across a rural–urban land-use discontinuum

Urbanization negatively impacts the diversity of aquatic insect assemblages in headwater streams and can lead to the homogenization of insect communities at the regional level. However, less is known about the impact of urbanization on insects in headwater streams within smaller cities that have significant upstream portions outside of urban land use. We collected insects monthly from April to September in 2014 and 2015 from five streams that flowed from rural upstream through urban downstream land use, plus two rural reference streams, in Greater Binghamton, New York, in the northeast USA. While urbanization was associated with lower insect taxonomic richness ( $$\bar{\alpha }$$ ) and elevated stream water conductivity, the regional diversity (γ) was similar among urban and rural land use. This corresponded to higher dissimilarity among urban sites (β) than among rural sites. To our knowledge, this is the first report of higher urban stream insect community β-diversity. Our results suggest that urbanization in this medium-sized city negatively impacts stream insect richness, but the change of community assemblages is not homogenous across the urban landscape. Connectivity between upstream rural sites and downstream urban sites may provide some relief from the impacts of urbanization in smaller cities.

The Predaceous Diving Beetle Fauna (Coleoptera: Dytiscidae) in Highway-Associated Aquatic Habitats in Southern Mississippi, USA

Highway-associated, lentic freshwater habitats are ubiquitous throughout the landscape of the southern USA and support diverse assemblages of aquatic insects. However, because of their generally small size, dynamic hydro-period, and disturbed nature, these habitats are often overlooked by naturalists, and subsequently faunal surveys are rare. This work addressed this knowledge gap by specifically surveying for a common and widespread group of beetles within these habitats, predaceous diving beetles (Coleoptera: Dytiscidae). Semi-permanent and ephemeral freshwater habitats associated with two major state highways and one interstate highway were sampled in early and late summer of 2009 within a 40-km radius of Hattiesburg, MS. Among 15 tire ruts, 18 ditches, and 30 ponds, we collected 861 adult and 545 larval dytiscids representing 18 different species. Our findings suggest that highway-associated, freshwater habitats may act as important habitat and dispersal “stepping-stones” for certain species of dytiscids in the landscape and likely play a part in maintaining the metapopulations and regional biodiversity of these taxa.

Incorporation of zinc and copper by insects of different functional feeding groups in agricultural streams.

Metals from agricultural areas are responsible for soil contamination and are carried into aquatic ecosystems. In this context, we evaluated the incorporation of zinc and copper via three feeding strategies (shredding, herbivory and predators) in assemblages of stream insects. We collected aquatic insects in five agricultural streams and five natural streams in Atlantic forest biome to investigate the accumulation of copper and zinc in insects with different feeding strategies. We found no significant differences in the concentrations of copper and zinc between stream types among all insect-feeding groups compared. However, we observed that copper accumulate concentrations differed significantly among the shredders and predators in relation to their resource in streams, while zinc concentrations differed in the two feeding strategy. Therefore, the investigation of the transfer of copper and zinc by different feeding strategies in streams can contribute to the understanding of changes in aquatic insect assemblages related to agricultural activities around streams.

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.

Forecasting the impact of an invasive macrophyte species in the littoral zone through aquatic insect species composition

Invasive macrophytes threaten freshwater ecosystem biodiversity. We analyzed the impact of the invasive white ginger lily ( Hedychium coronarium Konig J, 1783.– Zingiberaceae) on aquatic insect assemblages living in the littoral zone of a tropical reservoir. We took aquatic insect samples in the littoral zone on four main vegetal profile banks: white ginger monotypic bank, forest partially invaded, native macrophyte monotypic bank and riparian forest. At each vegetal bank, we measured abiotic variables such as dissolved oxygen, pH, water temperature and depth. We analyzed the aquatic insects through abundance, richness and Simpson diversity. We used the non-Metric Multidimensional Scaling (nMDS) analysis to analyze the spatial distribution of each assemblage, and Analysis of similarities (ANOSIM) to verify differences amongst dissimilarity distances. Additionally, we analyzed the main taxa associated with invasive macrophytes through indicator species analyses using IndVal index. We observed that the invasive macrophyte banks presented higher abundance of associated specimens, as well as lower dissimilarity of aquatic insect assemblages. Additionally, invasive macrophytes shifted the water pH and littoral depth of reservoir banks. The IndVal index indicated eight aquatic insects as indicator species. Labrundinia unicolor Silva, 2013 , Ablabesmyia depaulai Neubern, 2013 and Diastatops Rambur, 1842 were indicator species on banks. We concluded that invasion of white ginger lily caused loss of shallow littoral habitat and altered the pH of the surrounding water probably by high decomposition rate and high production of plant biomass. We suggest the use of species of aquatic insects as indicator species to monitor white ginger lily impact in freshwater systems.

Local and regional effects structuring aquatic insect assemblages at multiple spatial scales in a Mainland-Island region of the Atlantic Forest

Species diversity can be a result of environmental and spatial constrains that act at small and large spatial scales. An important question in community ecology is to know the contribution of each one in studies with multiple spatial scales. We examined aquatic insect assemblages in small streams from the Atlantic Forest in a mainland-island scenario, with the aim of measuring which variables explain the β-diversity of insects at three spatial scales (streams, ecoregions, mainland-island). We sampled 20 streams across four ecoregions, two on the mainland and two on the island. Spatial distribution of streams was hierarchical and ecoregions were isolated. The β-diversity decreased with increasing spatial scale, where higher values were found among streams and not among ecoregions or mainland-island. Our results indicate that the contribution of environmental and spatial predictors to the β-diversity of aquatic insect varies according to the scale of observation. Environmental variables of water and riparian forest had a greater effect on β-diversity among stream sites, while spatial and landscape (physical barriers) variables seem to be key factors at larger scales (ecoregions and mainland-island, respectively), which can prevent dispersal. Our study shows that local environmental heterogeneity had a great importance for maintaining regional diversity of aquatic insects.

Response of aquatic insect assemblages to the activities of traditional populations in eastern Amazonia

This study investigated the effects of activities carried out by traditional populations on aquatic ecosystems using the assemblages of Ephemeroptera, Plecoptera, and Trichoptera insect orders, and identified fluvial habitat characteristics modified by the disturbances. We surveyed two groups of streams—17 streams representing control conditions (CON) and 17 streams influenced by traditional population settlements (TPO). Genera richness and abundance of individuals did not vary between groups. With regard to physical habitat metrics, the percentage of leaf litter, amount of woody debris in the channel, proximity to farming, percentage of slow water in the channel, and the mean riparian vegetation cover all influenced benthic macroinvertebrate assemblages. Considerable differences were found in genera composition between the two groups. The genera Ulmeritoides, Miroculis, and Brasilocaenis were associated with the CON group, and Macronema and Campsurus with the TPO group. We conclude that even small-scale impacts, such as those performed by traditional Amazonian populations, can have major effects on aquatic biota, which reiterates the fragile nature of these ecosystems and emphasizes the need for adequate management of these activities.

Comparative ecotoxicity of imidacloprid and dinotefuran to aquatic insects in rice mesocosms

There are growing concerns about the impacts of neonicotinoid insecticides on ecosystems worldwide, and yet ecotoxicity of many of these chemicals at community or ecosystem levels have not been evaluated under realistic conditions. In this study, effects of two neonicotinoid insecticides, imidacloprid and dinotefuran, on aquatic insect assemblages were evaluated in experimental rice mesocosms. During the 5-month period of the rice-growing season, residual concentrations of imidacloprid were 5–10 times higher than those of dinotefuran in both soil and water. Imidacloprid treatment (10kg/ha) reduced significantly the populations of, Crocothemis servilia mariannae and Lyriothemis pachygastra nymphs, whereas those of Orthetrum albistylum speciosum increased slightly throughout the experimental period. However, Notonecta triguttata, which numbers were high from the start, later declined, indicating possible delayed chronic toxicity, while Guignotus japonicus disappeared. In contrast, dinotefuran (10kg/ha) did not decrease the populations of any species, but rather increased the abundance of some insects, particularly Chironominae spp. larvae and C. servilia mariannae nymphs, with the latter being 1.7x higher than those of controls. This was an indirect effect resulting from increased prey (e.g., chironomid larvae) and lack of competition with other dragonfly species. The susceptibilities of dragonfly nymphs to neonicotinoids, particularly imidacloprid, were consistent with those reported elsewhere. In general, imidacloprid had higher impacts on aquatic insects compared to dinotefuran.

The invasive white ginger lily (Hedichium coronarium) simplifies the trait composition of an insect assemblage in the littoral zone of a Savanna reservoir

The invasive white ginger lily (Hedichium coronarium – J. Köenig, 1783) simplifies the trait composition of an insect assemblage in the littoral zone of a Savanna reservoir. Invasive plants are believed to shift the trait composition of aquatic insects dwelling in banks of lentic ecosystems. In this study, we analyzed the relationship between the presence of the invasive white ginger lily (H. coronarium) and the functional trait indices of the aquatic insect assemblage in the littoral zone of a tropical reservoir. We sampled aquatic insects on the invaded and non-invaded banks of the reservoir and then analyzed the insect trait indices by estimating the Functional Dispersion (FDis), Functional Evenness (FEve) and the Functional Divergence (FDiv), as well as the Community level Weight-Mean traits (CWM). Finally, we compared these indices between invaded and non-invaded banks as well as their relationship with the abiotic variables, such as dissolved oxygen, pH, depth and water temperature. The result confirmed that the invaded banks had lower values of functional indices as well as dissolved oxygen. However, this abiotic variable was found to have no effect on the functional indices. In addition, the white ginger lily bank presented higher contribution of collector-gathering to predator-piercer groups. We suggest that the invasion of white ginger lily promotes low heterogeneity habitat resulting in simplification on functional traits of aquatic insect assemblage.