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Distribution, characters and habitats of Coenagrion spp. in the Russian part of the Caucasus is considered, chiefly by the authors' own data. There are seven species, of which C. australocaspicum Dumont & Heidari, 1996 is for the first time recorded in Russia (Dagestan), C. ornatum (Selys, 1850) and C. scitulum (Rambur, 1842) in Karachay-Cherkess and Dagestan Republics and C. pulchellum (Vander Linden, 1825) in Dagestan. Coenagrion lunulatum is still known from the territory only by a century-old record by A.N. Bartenev from the highlands of West Caucasus. Keys for identification of the Caucasian species of the puella-group in a broad sense-C. australocaspicum, C. puella (Linnaeus, 1758), C. pulchellum and C. ponticum (Bartenef, 1929)-are provided. Coenagrion ponticum is supposed to be a hybridogenic species resulting from hybridiisation between C. puella and C. pulchellum in the past. Three of the EPIC (exon-primed intron-crossing) molecular markers, AgT, MLC and PRMT, were sequenced from the above mentioned puella-group spp. and C. ornatum, from the territory considered and elsewhere, plus from C. persicum (Lohmann, 1993) from Iran. Coenagrion ponticum thus entered molecular analysis for the first time. Coenagrion australocaspicum appeared divergent from the rest of the group. Coenagrion ponticum appeared inside the cluster of C. pulchellum while C. persicum outside it, so the species status of the former is challenged while that of the latter confirmed. The joint tree showed two clades in C. puella (with no difference in outer characters), one composed of specimens originating from the regions to the south of the Main Caucasian Range and from the Caspian areas of Dagestan including foothills, and the other with specimens from Inner Dagestan (plus one locality in the Caspian-faced foothills), West Caucasus, Western Europe, Ural and West Siberia.

The final instar larva of the genus Dysphaea Selys, 1853 is described and figured for the first time based on specimens of D. gloriosa Fraser, 1938 from Khao Yai National Park, Thailand. The larvae of D. gloriosa are very rarely encountered. The larvae are characterized by the relatively larger head, the swollen heavily spined genae extending well beyond the eyes, the swollen postocular lobes bearing a disordered row of dense strong marginal spines, the outer armature of the mandibles and the unusual labrum. Notes on the habitat and biology of the larvae are also provided.

Disturbance (e.g. loss of plant cover) increases ambient temperature which can be lethal for ectotherm insects especially in hot places. We compared the thorax temperatures of 26 odonate species as a function of body size, habitat quality ("conserved" and cooler vs "perturbed" and warmer) and suborder (Anisoptera vs Zygoptera), as well as critical thermal maximum (CTmax) and as a function of habitat quality in Argia pulla (Zygoptera) and Orthemis ferruginea (Anisoptera). We expected thorax temperatures to differ between suborders based on their differences in body size and habitat quality status, and that populations in perturbed sites would have higher critical thermal maxima compared to those in conserved sites. This study was done in a tropical region with high ambient temperatures. Anisopterans had a higher body temperature than zygopterans, with no difference between habitats. Thoracic and air temperature were positively related, yet body temperatures were higher than the ambient temperature. A. pulla had higher CTmax in the perturbed sites, while O. ferruginea showed the opposite trend. Microenvironmental changes increase the ambient temperature, perhaps filtering insect species. The apparent resilience of odonates to disturbance should be examined more closely (using more species), especially in small species like the zygopterans which appear to be more strongly affected by ambient temperature., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The accumulation of scientific knowledge is far outstripped by the rate of environmental disturbance from human activities in aquatic habitats. This highlights the need to develop effective proxy measures of aquatic biodiversity that can demonstrate changes in communities associated with human activities. We evaluated whether the relative abundance and species richness of Anisoptera and Zygoptera can be used as a tool to measure environmental impacts on Amazonian streams. Adult of Anisoptera and Zygoptera were sampled in 50 Amazonian streams, in the municipality of Paragominas (Pará state), Brazil, using an entomological handnet. The physical features of each stream were evaluated using an index of environmental integrity (HII). We collected a total of 1769 Odonata specimens, representing 97 species (56 were Zygoptera and 41 were Anisoptera). Habitat modification resulted in an inversion in the proportional abundance and species richness of Anisoptera and Zygoptera, where Zygoptera diversity decreased with the loss of habitat integrity, whereas Anisoptera diversity increased with habitat disturbance. A decline of 0.1 in the habitat integrity index score resulted in an increase of approximately 13 individuals and 11 species of Anisoptera, with the exact opposite effect observed for the Zygoptera. In summary, the Odonata proved to be a useful model for the assessment of Amazonian streams, with sites where more than 54% of the Odonata species were Zygoptera being classified as preserved, and those dominated by Anisoptera species (> 59%) being considered degraded. This approach has clear applications for environmental impact assessments, as it reduces the influence of sampling effort and collector experience on assessment outcomes, and does not rely upon specialist knowledge, given that members of the two suborders are easily distinguished from one and other in the field.

Acanthagrion marinae sp. nov. (Holotype male: BRASIL, Mato Grosso do Sul, Campo Grande, UFMS, 20°29'56.26''S - 54°36'48.43''W, 547m, leg. M.E. Rodrigues, 03.ii.2015, collection code: VZYG437, MLP) is described and illustrated on the basis of 15 males. The new species belongs to the apicale species group by having horns on S10 and sclerotized hooks on tip of distal segment of the genital ligula. It can be easily distinguished from other species of the group by a combination of characters of the genital ligulae (presence of setae on segment two; absence of setae at flexure; distal lateral lobes of segment three absent). Notes on habitat and a modification of previous keys for the species of the apicale group are provided.

Several reports suggested that rice seedling nursery-box application of some systemic insecticides (neonicotinoids and fipronil) is the cause of the decline in dragonfly species noted since the 1990s in Japan. We conducted paddy mesocosm experiments to investigate the effect of the systemic insecticides clothianidin, fipronil and chlorantraniliprole on rice paddy field biological communities. Concentrations of all insecticides in the paddy water were reduced to the limit of detection within 3 months after application. However, residuals of these insecticides in the paddy soil were detected throughout the experimental period. Plankton species were affected by clothianidin and chlorantraniliprole right after the applications, but they recovered after the concentrations decreased. On the other hand, the effects of fipronil treatment, especially on Odonata, were larger than those of any other treatment. The number of adult dragonflies completing eclosion was severely decreased in the fipronil treatment. These results suggest that the accumulation of these insecticides in paddy soil reduces biodiversity by eliminating dragonfly nymphs, which occupy a high trophic level in paddy fields.

Ecological diversification of aquatic insects has long been suspected to have been driven by differences in freshwater habitats, which can be classified into flowing (lotic) waters and standing (lentic) waters. The contrasting characteristics of lotic and lentic freshwater systems imply different ecological constraints on their inhabitants. The ephemeral and discontinuous character of most lentic water bodies may encourage dispersal by lentic species in turn reducing geographical isolation among populations. Hence, speciation probability would be lower in lentic species. Here, we assess the impact of habitat use on diversification patterns in dragonflies (Anisoptera: Odonata). Based on the eight nuclear and mitochondrial genes, we inferred species diversification with a model-based evolutionary framework, to account for rate variation through time and among lineages and to estimate the impact of larval habitat on the potentially nonrandom diversification among anisopteran groups. Ancestral state reconstruction revealed lotic fresh water systems as their original primary habitat, while lentic waters have been colonized independently in Aeshnidae, Corduliidae and Libellulidae. Furthermore, our results indicate a positive correlation of speciation and lentic habitat colonization by dragonflies: speciation rates increased in lentic Aeshnidae and Libellulidae, whereas they remain mostly uniform among lotic groups. This contradicts the hypothesis of inherently lower speciation in lentic groups and suggests species with larger ranges are more likely to diversify, perhaps due to higher probability of larger areas being dissected by geographical barriers. Furthermore, larger range sizes may comprise more habitat types, which could also promote speciation by providing additional niches, allowing the coexistence of emerging species., (© 2016 John Wiley & Sons Ltd.)

Metabarcoding is an emerging genetic tool to rapidly assess biodiversity in ecosystems. It involves high-throughput sequencing of a standard gene from an environmental sample and comparison to a reference database. However, no consensus has emerged regarding laboratory pipelines to screen species diversity and infer species abundances from environmental samples. In particular, the effect of primer bias and the detection limit for specimens with a low biomass has not been systematically examined, when processing samples in bulk. We developed and tested a DNA metabarcoding protocol that utilises the standard cytochrome c oxidase subunit I (COI) barcoding fragment to detect freshwater macroinvertebrate taxa. DNA was extracted in bulk, amplified in a single PCR step, and purified, and the libraries were directly sequenced in two independent MiSeq runs (300-bp paired-end reads). Specifically, we assessed the influence of specimen biomass on sequence read abundance by sequencing 31 specimens of a stonefly species with known haplotypes spanning three orders of magnitude in biomass (experiment I). Then, we tested the recovery of 52 different freshwater invertebrate taxa of similar biomass using the same standard barcoding primers (experiment II). Each experiment was replicated ten times to maximise statistical power. The results of both experiments were consistent across replicates. We found a distinct positive correlation between species biomass and resulting numbers of MiSeq reads. Furthermore, we reliably recovered 83% of the 52 taxa used to test primer bias. However, sequence abundance varied by four orders of magnitudes between taxa despite the use of similar amounts of biomass. Our metabarcoding approach yielded reliable results for high-throughput assessments. However, the results indicated that primer efficiency is highly species-specific, which would prevent straightforward assessments of species abundance and biomass in a sample. Thus, PCR-based metabarcoding assessments of biodiversity should rely on presence-absence metrics.

Environmental characteristics and spatial distances between sites have been used to explain species distribution in the environment, through Neutral (space) and Niche theory (environment) predictions. We evaluated the effects of spatial and environmental factors on Odonata larvae distribution along the Suiá-Missú River Basin, state of Mato Grosso. We tested the hypotheses that (1) the environment is the main factor structuring the community due to its ecophysiological requirements; and (2) the pattern, if present, is clearer for Zygoptera. Samples were made in 12 sites on the Suiá-Missú River Basin in three seasons (2007/2008), with a total of 1.382 Odonata larvae, comprising 10 families, 51 genera and 100 morphospecies. The Anisoptera were more abundant than Zygoptera, comprising 81% of all specimens. The environment affected Zygoptera (R=0.291; p=0.007) and was the main factor structuring the assembly. Thus, Niche theory was confirmed. The absence of this effect on Anisoptera may be due to the ecophysiological adaptations that enable it to occupy different habitats. Zygoptera larvae are indicators of changes in habitat structure. The effects of environmental variables on larvae ecology emphasize the strong relationship between these organisms and environmental integrity.

Habitat persistence should influence dispersal ability, selecting for stronger dispersal in habitats of lower temporal stability. As standing (lentic) freshwater habitats are on average less persistent over time than running (lotic) habitats, lentic species should show higher dispersal abilities than lotic species. Assuming that climate is an important determinant of species distributions, we hypothesize that lentic species should have distributions that are closer to equilibrium with current climate, and should more rapidly track climatic changes. We tested these hypotheses using datasets from 1988 and 2006 containing all European dragon- and damselfly species. Bioclimatic envelope models showed that lentic species were closer to climatic equilibrium than lotic species. Furthermore, the models over-predicted lotic species ranges more strongly than lentic species ranges, indicating that lentic species track climatic changes more rapidly than lotic species. These results are consistent with the proposed hypothesis that habitat persistence affects the evolution of dispersal.