Water toxicity in reservoirs after freshwater algae harvest

Blooms of microalgae and cyanobacteria increase every year, presenting great problems for the environment. Finding a way of harvesting these microalgae could be useful for water governance. Furthermore, the method should not cause cell lysis and should thus avoiding discharging toxins into the water. Three reservoirs were studied, two of them with eutrophication problems (As Conchas and A Baxe) and another (Salas) with no such problems. Three different harvesting methods were studied; electroflocculation (EF) with the application time being varied; centrifugation, with application times and speeds being varied; and finally, natural sedimentation. The highest efficiency was obtained in the culture from A Baxe, which had a higher initial absorbance value (1.664), using EF (90.64% for an application time of 2 min and 30 s) and centrifugation at 4000 rpm (92.25% for2 minutes, 92.73% for 5 min). Electrofloculation can obtain up to 84% more biomass than natural sedimentation alone. Sample toxicity was studied before and after harvesting using Microcystest and found to be higher after harvesting. It was observed that for the same sample, the higher the yield was the greater the toxicity was. For the A Baxe culture with an application time of 2 min, a speed of 2000 rpm and a yield of 87.02%, a toxicity figure of 0.94 μg/L was obtained, while for a speed of 4000 rpm the yield was 92.25% and the toxicity was 1.05 μg/L. The toxicity limit set by the World Health Organization (WHO) is 1 μg/L, and this small difference seems to be key. With these results, this study concludes that chlorophyll levels may interfere with the test used. Future tests or analyses should be developed so as to avoid such interference, which may alter the toxin values. Electroflocculation seems to be a promising method since it does not cause the lysis of "Microcystis aeruginosa", whereas the centrifugation method could give problems. Finally, it is worth highlighting the importance of performing toxin measurements after harvesting the microalgae to check that the method is viable in natural ecosystems

Widespread Wolbachia infection in an insular radiation of damselflies (Odonata, Coenagrionidae)

Wolbachia is one of the most common endosymbionts found infecting arthropods. Theory predicts symbionts like Wolbachia will be more common in species radiations, as host shift events occur with greatest frequency between closely related species. Further, the presence of Wolbachia itself may engender reproductive isolation, and promote speciation of their hosts. Here we screened 178 individuals belonging to 30 species of the damselfly genera Nesobasis and Melanesobasis — species radiations endemic to the Fiji archipelago in the South Pacific — for Wolbachia, using multilocus sequence typing to characterize bacterial strains. Incidence of Wolbachia was 71% in Nesobasis and 40% in Melanesobasis, and prevalence was also high, with an average of 88% in the Nesobasis species screened. We identified a total of 25 Wolbachia strains, belonging to supergroups A, B and F, with some epidemic strains present in multiple species. The occurrence of Wolbachia in both males and females, and the similar global prevalence found in both sexes rules out any strong effect of Wolbachia on the primary sex-ratio, but are compatible with the phenotype of cytoplasmic incompatibility. Nesobasis has higher species richness than most endemic island damselfly genera, and we discuss the potential for endosymbiont-mediated speciation within this group.Ministerio de Ciencia e Innovación | Ref. CGL2008-02799Ministerio de Economía y Competitividad | Ref. CGL2014-53140-

Nesobasis rito sp. nov. (Zygoptera: Coenagrionidae), a new species of forest damselfly from Vanua Levu, Fiji

Nesobasis rito sp. nov. (Holotype ♂, Fiji, Vanua Levu, Drawa, 31 v 2018, A. Rivas-Torres leg.) from the comosa group is here described, illustrated, diagnosed, and compared with morphologically close species of the genus. Nesobasis rito can be distinguished from its related congeners by the shape of the caudal appendages and the ligula. The most similar species are N. comosa and N. heteroneura, which, like N. rito, have the caudal appendages covered by dense setae (especially the first species), but the shape differs clearly in lateral view, with N. rito having longer and more slender appendages, and a basal tooth clearly seen in dorsal view, absent in other members of the comosa group. The specific status of the collected specimens is also supported by the results of genetic analyses, where N. rito appears as a well-supported monophyletic clade. Nesobasis rito also has a distinct distribution from its most similar congeners: it is found on Vanua Levu, while N. comosa is found on Viti Levu and the closely related N. heteroneura is found on Viti Levu and Ovalau. All species of this group are found in streams with native forest riparian vegetation on their respective islands

Molecular and morphological analyses support different taxonomic units for Asian and Australo-Pacific forms of Ischnura aurora (Odonata, Coenagrionidae)

Despite the great technological progress that has aided taxonomical identification, taxonomical issues remain for certain species found in remote and/or understudied geographical areas. The damselfly species Ischnura aurora has been the subject of a long-standing taxonomical debate, focused mainly on the existence of morphological and behavioural differences between Asian and Australo-Pacific forms of this species that could justify their placement into two different species. Here, we carried out a comparative morphological analysis of specimens currently identified as I. rubilio from India and I. aurora from Asia and Oceania, combined with the analysis of mitochondrial and nuclear sequence data, both developed by us and available in public repositories. Our results split the Asian and Australo-Pacific forms of I. aurora into two well-differentiated taxonomic units and, hence, different (albeit closely related) species, and support the specific status of I. rubilio. The results of our genetic analyses suggest the existence of a third (and even fourth) taxonomic unit, stressing the need to revise all available material belonging to the different I. aurora subspecies that have been described. Finally, we have identified several questionable DNA sequences currently available in public repositories, upon which previous conclusions about the phylogenetic position of I. rubilio are based. Our study stresses the importance of being able to link available DNA sequence data with voucher specimens as well as to carry out a careful examination of DNA sequence data prior to their inclusion in taxonomical studies.Ministerio de Economía y Competitividad | Ref. CGL2014-53140-PAgencia Estatal de Investigación | Ref. PGC2018-096656-B-I0

Darwin returns to the Galapagos: genetic and morphological analyses confirm the presence of Tramea darwini at the archipelago (Odonata, Libellulidae)

The status of the Tramea species present in the Galapagos Islands (Odonata, Libellulidae) has been the subject of a long-standing debate among odonatologists. Here, we use molecular and morphological data to analyze a series of specimens from this genus collected in 2018 from the Islands of San Cristobal, Isabela, and Santa Cruz, with the aim of determining their relationship with Tramea calverti Muttkowski and with their currently considered senior synonym T. cophysa Hagen. We combined sequencing of mitochondrial and nuclear DNA with morphological examination of several specimens of Tramea, including representatives of continental T. cophysa and T. calverti. Our molecular analyses place the Tramea from Galapagos in the same clade as T. calverti, with T. cophysa as a closely related species. The morphological analyses found only one consistent difference between T. cophysa and T. calverti: the presence of an accessory lobe in the male vesica spermalis of T. cophysa that is absent in T. calverti and in the Tramea from Galapagos. In agreement with our genetic results, the overall morphological differences documented by us indicate that the Galapagos material examined is conspecific with T. calverti. In light of this, and following the principle of priority in taxonomic nomenclature, Tramea calverti Muttkowski, 1910 should hereafter be considered a junior synonym of Tramea darwini Kirby, 1889.USFQ Collaboration Grants | Ref. 15782Ministerio de Economía y Competitivdad | Ref. CGL2014-53140-PAgencia Estatal de Investigación | Ref. PGC2018-096656-B-I0

Incidence and diversity of torix Rickettsia–Odonata symbioses

Heritable microbes are an important component of invertebrate biology, acting both as beneficial symbionts and reproductive parasites. Whilst most previous research has focussed on the ‘Wolbachia pandemic’, recent work has emphasised the importance of other microbial symbionts. In this study, we present a survey of odonates (dragonflies and damselflies) for torix group Rickettsia, following previous research indicating that this clade can be common in other aquatic insect groups. PCR assays were used to screen a broad range of odonates from two continents and revealed 8 of 76 species tested were infected with Rickettsia. We then conducted further deeper screening of UK representatives of the Coenagrionidae damselfly family, revealing 6 of 8 UK coenagrionid species to be positive for torix Rickettsia. Analysis of Rickettsia gene sequences supported multiple establishments of symbiosis in the group. Some strains were shared between UK coenagrionid species that shared mtDNA barcodes, indicating a likely route for mitochondrial introgression between sister species. There was also evidence of coinfecting Rickettsia strains in two species. FISH analysis indicated Rickettsia were observed in the ovarioles, consistent with heritable symbiosis. We conclude that torix Rickettsia represent an important associate of odonates, being found in a broad range of species from both Europe and South America. There is evidence that coinfection can occur, vertical transmission is likely, and that symbiont movement following hybridisation may underpin the lack of ‘barcoding gap’ between well-established species pairs in the genus. Future work should establish the biological significance of the symbioses observed.Ministerio de Ciencia e Innovación | Ref. CGL2008-0279

Mixed signals? Morphological and molecular evidence suggest a color polymorphism in some neotropical polythore damselflies

The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations. We here offer the first evidence for an elaborate wing polymorphism in the Neotropical damselfly genus Polythore, which consists of 21 described species, distributed along the eastern slopes of the Andes in South America. These damselflies display highly complex wing colors and patterning, incorporating black, white, yellow, and orange in multiple wing bands. Wing colors, along with some components of the male genitalia, have been the primary characters used in species description; few other morphological traits vary within the group, and so there are few useful diagnostic characters. Previous research has indicated the possibility of a cryptic species existing in P. procera in Colombia, despite there being no significant differences in wing color and pattern between the populations of the two putative species. Here we analyze the complexity and diversity of wing color patterns of individuals from five described Polythore species in the Central Amazon Basin of Peru using a novel suite of morphological analyses to quantify wing color and pattern: geometric morphometrics, chromaticity analysis, and Gabor wavelet transformation. We then test whether these color patterns are good predictors of species by recovering the phylogenetic relationships among the 5 species using the barcode gene (COI). Our results suggest that, while highly distinct and discrete wing patterns exist in Polythore, these "wingforms" do not represent monophyletic clades in the recovered topology. The wingforms identified as P. victoria and P. ornata are both involved in a polymorphism with P. neopicta; also, cryptic speciation may have taking place among individuals with the P. victoria wingform. Only P. aurora and P. spateri represent monophyletic species with a single wingform in our molecular phylogeny. We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it

Peruvian geographical population polymorphism statistics.

<p>Number of individuals (N), Number of haplotypes (h), haplotype diversity (Hd), genetic diversity (π), genetic diversity per segregating sites (θ(S)), and Tajima’s D test including significance.</p><p>Peruvian geographical population polymorphism statistics.</p

Mean wing shapes for <i>Polythore</i> wing morphs from landmark analysis.

<p>Fifty landmarks were taken from individuals of the 7 wing morphs, Procrustes superimposed, and averaged together for each wing morph. Outline landmarks (LMs 1–14) are dashed; color bands (LMs 15–50) are solid lines and numbered from I to VI. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0125074#pone.0125074.g002" target="_blank">Fig 2</a> and text for detailed description of landmarking protocol. M = male, and F = female.</p

Mixed Signals? Morphological and Molecular Evidence Suggest a Color Polymorphism in Some Neotropical <i>Polythore</i> Damselflies

<div><p>The study of color polymorphisms (CP) has provided profound insights into the maintenance of genetic variation in natural populations. We here offer the first evidence for an elaborate wing polymorphism in the Neotropical damselfly genus <i>Polythore</i>, which consists of 21 described species, distributed along the eastern slopes of the Andes in South America. These damselflies display highly complex wing colors and patterning, incorporating black, white, yellow, and orange in multiple wing bands. Wing colors, along with some components of the male genitalia, have been the primary characters used in species description; few other morphological traits vary within the group, and so there are few useful diagnostic characters. Previous research has indicated the possibility of a cryptic species existing in <i>P</i>. <i>procera</i> in Colombia, despite there being no significant differences in wing color and pattern between the populations of the two putative species. Here we analyze the complexity and diversity of wing color patterns of individuals from five described <i>Polythore</i> species in the Central Amazon Basin of Peru using a novel suite of morphological analyses to quantify wing color and pattern: geometric morphometrics, chromaticity analysis, and Gabor wavelet transformation. We then test whether these color patterns are good predictors of species by recovering the phylogenetic relationships among the 5 species using the barcode gene (COI). Our results suggest that, while highly distinct and discrete wing patterns exist in <i>Polythore</i>, these “wingforms” do not represent monophyletic clades in the recovered topology. The wingforms identified as <i>P</i>. <i>victoria</i> and <i>P</i>. <i>ornata</i> are both involved in a polymorphism with <i>P</i>. <i>neopicta</i>; also, cryptic speciation may have taking place among individuals with the <i>P</i>. <i>victoria</i> wingform. Only <i>P</i>. <i>aurora</i> and <i>P</i>. <i>spateri</i> represent monophyletic species with a single wingform in our molecular phylogeny. We discuss the implications of this polymorphism, and the potential evolutionary mechanisms that could maintain it.</p></div