Spatio-temporal variability in the Cladocera assemblage of a subtropical hypersaline lagoon / Variabilidade espaço-temporal da assembleia de Cladocera de uma lagoa hipersalina subtropical

Cladocera represent an important zooplankton group because of their seasonal prominence in terms of abundance and their contribution in controlling primary production (phytoplankton). On a global scale, there are few studies on Cladocera in hypersaline environments. The present work aims to evaluate the spatio-temporal variation of the Cladocera assemblage across a salinity gradient in the habitats of the Araruama Lagoon. Samples were collected in random months over a period of four years at 12 fixed stations in the Araruama Lagoon using a WP2 plankton net equipped with a flow meter. Our results do not reveal significant influence of the tide and seasonal variation as factors affecting the Cladocera assemblage. Five Cladocera species were found in the Araruama Lagoon, only in stations 11 and 12 where they reached an average of 1,799 ± 3,103 ind. m-³. The mean of the Shannon Diversity Index was 0.45 ± 0.2. The species that stood out in terms of frequency and abundance were: Penilia avirostris (frequency of occurrence: 71%), followed by Pseudevadne tergestina (41%). The same species also stood out in terms of relative abundance, Penilia avirostris (87%) and Pseudevadne tergestina (11%). The absence of Cladocera in the innermost parts of the lagoon suggests that their entrance to these locations is possibly inhibited by the salinity and temperature gradient of the lagoon, being the main factors influencing the dynamics of the Cladocera assemblages.(AU)

Os cladóceros representam um importante grupo de zooplâncton, devido ao seu destaque sazonal em termos de abundância e à sua contribuição no controlo da produção primária (fitoplâncton). Em escala global, há poucos estudos com Cladocera em ambientes hipersalinos. O presente trabalho tem como objetivo avaliar a variação espaço-temporal da assembleia de Cladocera em um gradiente de salinidades da Lagoa de Araruama. As amostras foram coletadas em meses aleatórios, durante um período de quatro anos, em 12 estações fixas na Lagoa de Araruama, utilizando uma rede de plâncton WP2 equipada com um fluxômetro. Os nossos resultados não revelam uma influência significativa da maré e da variação sazonal como fatores que afetam a assembleia de Cladocera. Cinco espécies de Cladocera foram encontradas na Lagoa de Araruama. A assembleia apresentou maior densidade absoluta estações 12 e 11, atingindo uma a média de 1.799 ± 3.103 inds-³. A média do Índice de Diversidade de Shannon foi de 0,45 ± 0,2. As espécies que se destacaram em termos de frequência e abundância foram: Penilia avirostris (frequência de ocorrência: 71%), seguida de Pseudevadne tergestina (41%). As mesmas espécies também se destacaram em termos de abundância relativa Penilia avirostris (87%) e Pseudevadne tergestina (11%). A ausência de Cladocera nas partes mais interiores da lagoa sugere que a sua entrada nestes locais é possivelmente inibida pela salinidade e gradiente de temperatura da lagoa, sendo os principais fatores que influenciam a dinâmica da assembleia de Cladocera.(AU)

Spatio-temporal variability in the Cladocera assemblage of a subtropical hypersaline lagoon / Variabilidade espaço-temporal da assembleia de Cladocera de uma lagoa hipersalina subtropical

Cladocera represent an important zooplankton group because of their seasonal prominence in terms of abundance and their contribution in controlling primary production (phytoplankton). On a global scale, there are few studies on Cladocera in hypersaline environments. The present work aims to evaluate the spatio-temporal variation of the Cladocera assemblage across a salinity gradient in the habitats of the Araruama Lagoon. Samples were collected in random months over a period of four years at 12 fixed stations in the Araruama Lagoon using a WP2 plankton net equipped with a flow meter. Our results do not reveal significant influence of the tide and seasonal variation as factors affecting the Cladocera assemblage. Five Cladocera species were found in the Araruama Lagoon, only in stations 11 and 12 where they reached an average of 1,799 ± 3,103 ind. m-³. The mean of the Shannon Diversity Index was 0.45 ± 0.2. The species that stood out in terms of frequency and abundance were: Penilia avirostris (frequency of occurrence: 71%), followed by Pseudevadne tergestina (41%). The same species also stood out in terms of relative abundance, Penilia avirostris (87%) and Pseudevadne tergestina (11%). The absence of Cladocera in the innermost parts of the lagoon suggests that their entrance to these locations is possibly inhibited by the salinity and temperature gradient of the lagoon, being the main factors influencing the dynamics of the Cladocera assemblages.

Os cladóceros representam um importante grupo de zooplâncton, devido ao seu destaque sazonal em termos de abundância e à sua contribuição no controlo da produção primária (fitoplâncton). Em escala global, há poucos estudos com Cladocera em ambientes hipersalinos. O presente trabalho tem como objetivo avaliar a variação espaço-temporal da assembleia de Cladocera em um gradiente de salinidades da Lagoa de Araruama. As amostras foram coletadas em meses aleatórios, durante um período de quatro anos, em 12 estações fixas na Lagoa de Araruama, utilizando uma rede de plâncton WP2 equipada com um fluxômetro. Os nossos resultados não revelam uma influência significativa da maré e da variação sazonal como fatores que afetam a assembleia de Cladocera. Cinco espécies de Cladocera foram encontradas na Lagoa de Araruama. A assembleia apresentou maior densidade absoluta estações 12 e 11, atingindo uma a média de 1.799 ± 3.103 inds-³. A média do Índice de Diversidade de Shannon foi de 0,45 ± 0,2. As espécies que se destacaram em termos de frequência e abundância foram: Penilia avirostris (frequência de ocorrência: 71%), seguida de Pseudevadne tergestina (41%). As mesmas espécies também se destacaram em termos de abundância relativa Penilia avirostris (87%) e Pseudevadne tergestina (11%). A ausência de Cladocera nas partes mais interiores da lagoa sugere que a sua entrada nestes locais é possivelmente inibida pela salinidade e gradiente de temperatura da lagoa, sendo os principais fatores que influenciam a dinâmica da assembleia de Cladocera.

Distribution of planktonic microcrustaceans (Cladocera and Copepoda) in lentic and lotic environments from the semiarid region in northeastern Brazil

The present study aimed to inventory the biodiversity of planktonic microcrustaceans (Cladocera and Copepoda) in 44 environments from the semiarid region of Brazil, increasing the knowledge about zooplankton community, including phytophilous species. Between 2011 and 2017, organisms were collected in a non - systematic way in the states of Rio Grande do Norte, Pernambuco, Ceará and Paraíba. A total of 60 species of planktonic microcrustaceans were identified, of which 52 were cladocerans and eight were copepods. The basin that presented the highest richness was Pajeú River with 41 species. Nevertheless, the extrapolated number of species shows an increasing tendency for this basin. The genus composition was different between the basins, with Moxotó basin (Pernambuco) being isolated from the others, probably since lagoons were the only type of environment sampled in this basin. Richness and abundance patterns were higher for the basins where sampling was mainly performed in lentic environments, such as Pajeú and Moxotó. Microcrustacean inventories and long-term studies need to be conducted more frequently to better understand the biodiversity of continental aquatic ecosystems in the semiarid region of Brazil.(AU)

O presente estudo objetivou inventariar a biodiversidade de microcrustáceos planctônicos (Cladocera e Copepoda) em 44 mananciais da região semiárida do Brazil, ampliando o conhecimento da comunidade zooplanctônica desta região, incluindo as espécies fitófilas. Os organismos foram coletados de modo não sistemático entre 2011 e 2017, nos estados do Rio Grande do Norte, Pernambuco, Ceará e Paraíba. Um total de 60 espécies de microcrustáceos planctônicos foram identificadas, sendo 52 de cladóceros e oito de copépodes. A bacia que apresentou maior riqueza foi a do rio Pajeú com 41 espécies. Mesmo assim, o número extrapolado de espécies mostra tendência de aumento para essa bacia. A composição dos gêneros foi diferente entre as bacias hidrográficas, sendo a bacia do Moxotó (Pernambuco) isolada das demais, talvez porque nesta bacia as lagoas foram o único tipo de ambiente amostrado. Os padrões de riqueza e de abundância se mostraram mais elevados para as bacias ondem a amostragem foi realizada principalmente em ambientes lênticos, como a do Pajeú e do Moxotó. Inventários de microcrustáceos e estudos de longa duração precisam ser maximizados para ampliação do conhecimento da biodiversidade dos ecossistemas aquáticos continentais da região semiárida brasileira.(AU)

Distribution of planktonic microcrustaceans (Cladocera and Copepoda) in lentic and lotic environments from the semiarid region in northeastern Brazil

The present study aimed to inventory the biodiversity of planktonic microcrustaceans (Cladocera and Copepoda) in 44 environments from the semiarid region of Brazil, increasing the knowledge about zooplankton community, including phytophilous species. Between 2011 and 2017, organisms were collected in a non - systematic way in the states of Rio Grande do Norte, Pernambuco, Ceará and Paraíba. A total of 60 species of planktonic microcrustaceans were identified, of which 52 were cladocerans and eight were copepods. The basin that presented the highest richness was Pajeú River with 41 species. Nevertheless, the extrapolated number of species shows an increasing tendency for this basin. The genus composition was different between the basins, with Moxotó basin (Pernambuco) being isolated from the others, probably since lagoons were the only type of environment sampled in this basin. Richness and abundance patterns were higher for the basins where sampling was mainly performed in lentic environments, such as Pajeú and Moxotó. Microcrustacean inventories and long-term studies need to be conducted more frequently to better understand the biodiversity of continental aquatic ecosystems in the semiarid region of Brazil.

O presente estudo objetivou inventariar a biodiversidade de microcrustáceos planctônicos (Cladocera e Copepoda) em 44 mananciais da região semiárida do Brazil, ampliando o conhecimento da comunidade zooplanctônica desta região, incluindo as espécies fitófilas. Os organismos foram coletados de modo não sistemático entre 2011 e 2017, nos estados do Rio Grande do Norte, Pernambuco, Ceará e Paraíba. Um total de 60 espécies de microcrustáceos planctônicos foram identificadas, sendo 52 de cladóceros e oito de copépodes. A bacia que apresentou maior riqueza foi a do rio Pajeú com 41 espécies. Mesmo assim, o número extrapolado de espécies mostra tendência de aumento para essa bacia. A composição dos gêneros foi diferente entre as bacias hidrográficas, sendo a bacia do Moxotó (Pernambuco) isolada das demais, talvez porque nesta bacia as lagoas foram o único tipo de ambiente amostrado. Os padrões de riqueza e de abundância se mostraram mais elevados para as bacias ondem a amostragem foi realizada principalmente em ambientes lênticos, como a do Pajeú e do Moxotó. Inventários de microcrustáceos e estudos de longa duração precisam ser maximizados para ampliação do conhecimento da biodiversidade dos ecossistemas aquáticos continentais da região semiárida brasileira.

Spatial and temporal distribution of gerrid (Heteroptera) and predation on microcrustaceans from a tropical shallow lake / Distribuição espacial e temporal de gerrídeo (Heteroptera) e a predação sobre microcrustáceos de um lago tropical raso

Abstract Predator-prey interactions involving an aquatic insect and zooplanktonic prey of different sizes were investigated to quantify prey mortality exposed to predators. Laboratory experiments were undertaken with the young and adult gerrid Rheumatobates crassifemur to test predation and size selectivity on the cladocerans Daphnia gessneri, Ceriodaphnia richardi, and Bosmina tubicen. Population fluctuations and spatial distribution of the gerrid were also evaluated in a small and shallow Brazilian lake throughout 12 months in fortnightly samples. The insects were more abundant in the littoral (mean density 7.0 ± 1.2 ind.m-2) compared to the limnetic zone. The period with the highest densities was late January to June, in both zones. Predation by young instars on Daphnia and Ceriodaphnia was significant (mean ingestion rate of 1.3 ± 0.1 D. gessneri and 0.7 ± 0.1 C. richardi per predator per hour). Adult insect fed only the large-sized prey (mean ingestion rate of 1.0 ± 0.1 D. gessneri per predator per hour). Young gerrids have greater potential to prey on cladocerans than adults, and size selectivity occurred for both predators. Preference of adults by the larger prey is probably related to difficulties in manipulating smaller planktonic prey, such as Ceriodaphnia. Due to higher densities of insects in the littoral, higher predation on zooplankton in this zone is expected. This study does contribute to a better understanding of trophic interactions in tropical shallow lakes and is the first to investigate predation of a gerrid on cladocerans in laboratory experiments.

Resumo Foram investigadas as interações predador-presa, envolvendo inseto aquático e presas zooplanctônicas de diferentes tamanhos para quantificar a mortalidade das presas expostas a predadores. Experimentos de laboratório foram realizados com jovens e adultos do gerrídeo Rheumatobates crassifemur para testar a predação e a seletividade por tamanho das espécies de cladóceros Daphnia gessneri, Ceriodaphnia richardi e Bosmina tubicen. Flutuações populacionais e a distribuição espacial do gerrídeo também foram avaliadas em um lago brasileiro pequeno e raso durante 12 meses em amostras quinzenais. Os insetos foram mais abundantes no litoral (densidade média 7,0 ± 1,2 ind.m-2) em comparação com a zona limnética. Maiores densidades ocorreram de fim de janeiro a junho, em ambas as zonas. A predação dos jovens foi significativa sobre Daphnia e Ceriodaphnia (taxa de ingestão média 1,3 ± 0,1 D. gessneri and 0,7 ± 0,1 C. richardi por predador por hora). Adultos predaram somente a presa maior (taxa de ingestão média 1,0 ± 0,1 D. gessneri por predador por hora). Gerrídeos jovens têm um maior potencial para predar cladóceros que os adultos, e seletividade por tamanho ocorreu para ambos. A preferência dos adultos somente pela presa maior provavelmente está relacionada à dificuldade em manipular pequenas presas planctônicas como Ceriodaphnia. Devido às maiores densidades de insetos no litoral, é esperada maior predação sobre o zooplâncton nesta zona. Este estudo contribui para uma melhor compreensão sobre interações tróficas em lagos tropicais rasos e é o primeiro a investigar a predação de um gerrídeo sobre cladóceros em experimentos de laboratório.

Spatial and temporal distribution of gerrid (Heteroptera) and predation on microcrustaceans from a tropical shallow lake.

Predator-prey interactions involving an aquatic insect and zooplanktonic prey of different sizes were investigated to quantify prey mortality exposed to predators. Laboratory experiments were undertaken with the young and adult gerrid Rheumatobates crassifemur to test predation and size selectivity on the cladocerans Daphnia gessneri, Ceriodaphnia richardi, and Bosmina tubicen. Population fluctuations and spatial distribution of the gerrid were also evaluated in a small and shallow Brazilian lake throughout 12 months in fortnightly samples. The insects were more abundant in the littoral (mean density 7.0 ± 1.2 ind.m-2) compared to the limnetic zone. The period with the highest densities was late January to June, in both zones. Predation by young instars on Daphnia and Ceriodaphnia was significant (mean ingestion rate of 1.3 ± 0.1 D. gessneri and 0.7 ± 0.1 C. richardi per predator per hour). Adult insect fed only the large-sized prey (mean ingestion rate of 1.0 ± 0.1 D. gessneri per predator per hour). Young gerrids have greater potential to prey on cladocerans than adults, and size selectivity occurred for both predators. Preference of adults by the larger prey is probably related to difficulties in manipulating smaller planktonic prey, such as Ceriodaphnia. Due to higher densities of insects in the littoral, higher predation on zooplankton in this zone is expected. This study does contribute to a better understanding of trophic interactions in tropical shallow lakes and is the first to investigate predation of a gerrid on cladocerans in laboratory experiments.

A new subspecies of Ovalona setulosa (Megard, 1967) (Cladocera: Anomopoda: Chydoridae) from the Caribbean coast of Colombia.

A new subspecies of Ovalona setulosa (Megard, 1967) (Cladocera: Anomopoda: Chydoridae) is described based on material from Laguna Navío Quebrado (La Guajira Department), Colombia. Ovalona setulosa arangureni ssp. nov. differs from the nominative subspecies in: (1) major head pores position on head shield; (2) posterior margin of labral keel without clusters of short setules; (3) more elongated postabdomen, with length/height ratio about 2.7-3; (4) male postabdomen with straight dorsal margin in whole distal portion. In outer morphology and morphology of postabdomen, O. setulosa arangureni ssp. nov. can be confused with O. glabra (Sars, 1901), but, like nominative subspecies, differs from it by interrupted connection between major head pores. Our data suggest that diversity of Aloninae species with limited distribution areas in South America is underestimated yet, and areas north and south of Amazon basin can have different local species.

Continuity effects on rotifers and microcrustaceans caused by the construction of a downstream reservoir in a cascade series (Iguaçu River, Brazil) / Efeitos contínuos sobre rotíferos e microcrustáceos causados pela construção de um reservatório a jusante de uma série em cascata, Rio Iguaçú, Brasil

Abstract This study evaluated changes in the community of rotifers and microcrustaceans associated with the construction of a large and dendritic reservoir in Iguaçu River (Brazil), as the last reservoir of a sequence of five cascading systems. Differences were clear between pre-filling and post-filling phases for organisms and some of environmental variables. In the pre-filling phase, the community was more homogeneous along the downstream river gradient, and spatial compartmentalization in the new reservoir was common during the post-filling phase. From 140 identified taxa, 10 species occurred exclusively in the pre-filling phase and 32 in the post-filling phase. After completion of the fifth reservoir filling-up, opportunistic, pioneer and fast-developing species quickly dominated, and downstream of the fourth reservoir the pre-filling decreasing gradient of richness, diversity and evenness disappeared. Richness of rotifers and cladocerans, cladocerans diversity, and evenness of rotifers, cladocerans and copepods were generally higher in the post-filling phase. A non-metric multidimensional analysis based on a presence/absence matrix depicted a homogeneous and dense group of species associated to the pre-filling phase and a second, dispersed group related to the post-filling phase. Spearman correlations pointed out significant positive effects of transparency on rotifer species richness in the post-filling phase, and negative effects on the microcrustacean richness in the pre-filling phase. Dam construction caused disruption of the downstream lotic gradient along the series of dams, leading to the development of distinct species in lentic spatial compartments.(AU)

Resumo Esse estudo analisou os efeitos da construção de um reservatório largo e dendrítico no Brasil sobre a comunidade de rotíferos e microcrustáceos, sendo o último reservatório de uma cascata de cinco. Houve claras diferenças entre as fases pré e pós-enchimento para os organismos e para algumas variáveis ambientais. Na fase pré-enchimento, a comunidade foi mais homogênea no gradiente longitudinal no rio a jusante, e na fase pós-enchimento houve compartimentalização espacial no novo reservatório. Dos 140 táxons identificados, dez espécies ocorreram exclusivamente na fase pré-enchimento e 32 na fase pós-enchimento. Após o enchimento, espécies oportunistas, pioneiras e de rápido desenvolvimento foram dominantes, e desapareceu o gradiente de decréscimo a jusante do quarto reservatório para a riqueza, diversidade e equitabilidade durante a fase pré-enchimento. A riqueza de rotíferos e cladóceros, a diversidade de cladóceros, e a equitabilidade de rotíferos, cladóceros e copépodes foram elevadas na fase pós-enchimento. A análise de escalonamento multidimensional não-métrico sobre a matriz de presença e ausência mostrou um grupo homogêneo e denso de espécies e meses de amostragem na fase pré-enchimento, e outro grupo disperso na fase pós-enchimento. Correlações de Spearman apontaram efeitos significativos da transparência sobre a riqueza de rotíferos na fase pós-enchimento, e efeitos negativos sobre a riqueza de microcrustáceos na outra fase. Os efeitos da construção do reservatório causaram rompimento no gradiente lótico contínuo a jusante do quarto reservatório observado na fase pré-enchimento, permitindo o desenvolvimento de espécies em compartimentos espaciais lênticos.(AU)

Description of a new species of the costata-group (Cladocera, Chydoridae, Aloninae) from Brazil.

The aim of this study is to describe a new species of the costata-group from Brazil. Alona margipluma sp. nov. shares morphological traits with A. costata Sars, 1862, A. natalensis Sinev, 2008, and A. cheni Sinev, 1999, but differs from them in: (i) thin setulae between the marginal setae on the valves, (ii) setae 4-5 on the exopodite of limb III long and different in length, (iii) bottle-shaped sensillum on the basal endite of limb IV. For identification of Alona margipluma sp. nov. it is necessary to check carefully the main head pores and postabdomen characters since the former superficially resemble A. iheringula, A. setigera and Alona guttata.

Temperature and age affect the life history characteristics and fatty acid profiles of Moina macrocopa (Cladocera).

Demographic responses and fatty acid profiles of Moina macrocopa were quantified under different temperature regimes (20°C, 25°C and 30°C and diurnally variable 20-30°C) and at fixed ration (10.65µgDWml(-1)) of Chlorella. Highest constant temperature (30°C) reduced the density of M. macrocopa. The cladocerans under the fluctuating temperature regime too had lower population growth (about 50% lower than that at constant 25°C). The survivorship of M. macrocopa was higher at 20°C than that at 25°C and 30°C or at variable temperature regime. Gross and net reproductive rates were higher at 25°C. At 20°C, neonates had the highest proportion (67%) of myristic, palmitic and stearic acids while the adults had the lowest (26%) proportion. For both adults and neonates, palmitoleic, linoleic and linolenic comprised of 15-35% of the total fatty acids. Higher percentage (19%) of linoleic acid was present in adults than neonates (7%). Adults had linolenic acid level which was 3-times higher than in neonates. Linoleic and linolenic fatty acids decreased with increasing temperature for neonates and adults from 20°C to 30°C. The demographic responses and fatty acid profiles of M. macrocopa were discussed in relation to level and mode of temperature exposure.

A new species of Leberis Smirnov, 1989 (Cladocera: Chydoridae) from Colombia.

A new species of Leberis Smirnov 1989 (Cladocera: Chydoridae) is described based on the material from Ciénaga El Convento (Atlántico Department), Ciénaga Grande de Santa Marta (Magdalena Department), and Laguna Navío Quebrado (La Guajira Department), Colombia. In the Neotropics, Leberis colombiensis sp. nov. could be confused with L. davidi Richard, 1985. But the former differs from the latter in: (1) smaller size; (2) smaller post-pore distance; (3) gonopore region on male postabdomen un-inflated, not overhanging base of postabdominal claw; (4) shorter postanal portion of male postabdomen. Diversity of the genus worldwide is underestimated yet. We believe that more species of Leberis will be described in the future, i.e. after molecular genetic studies.

Effect of crude extracts of Dolichospermum planctonicum on the demography of Plationus patulus (Rotifera) and Ceriodaphnia cornuta (Cladocera).

In this study we evaluated the toxicological effects of crude extracts of Dolichospermum planctonicum on Plationus patulus (Rotifera) and Ceriodaphnia cornuta (Cladocera). The active compound from the laboratory-cultured cyanobacteria was extracted by lyophilizing it at -70 °C for 48 h, after which the sample was thawed. The cycle was repeated five times, and between each cycle the cells were sonicated to lyse them. Using the extract of Anabaena, experiments of population growth and life table demography of the two zooplankton species were compared in media with and without (controls) the cyanotoxins. In both experiments two toxic concentrations diluted in US EPA medium were used, one in a 5:15 proportion, and the other in a 2.5:17.5. We found that the rotifers were more resistant to the toxicants than the cladocerans. Their population growth rates ranged from 0.11 d(-1) in controls to 0.08 d(-1) in the presence of the crude extracts for P. patulus and from 0.18 in controls to -0.27 in the presence of the crude extracts for C. cornuta. The crude extract also had a significant negative impact on the demographic parameters, adversely affecting reproduction more than survival. The data have been discussed with emphasis on the importance of further research using cyanobacterial crude extracts.

Growth and development time of subtropical Cladocera Diaphanosoma birgei Korinek, 1981 fed with different microalgal diets.

The aim of this work was to investigate the growth performance of Diaphanosoma birgei fed with two Chlorophyceae algae, Ankistrodesmus gracilis and Haematococcus pluvialis using monoalgal diets and simpler mixed diets. D. birgei was daily fed on four treatments: 1) 100% Ankistrodesmus gracilis (Ag); 2) 100% Haematoccocus pluvialis (Hp); 3) 25% A. gracilis + 75% H. pluvialis (Ag-25+Hp-75) and 4) 75% A. gracilis + 25% H. pluvialis (Ag-75+Hp-25). The fecundity curve of D. birgei showed that the mixed feed Ag-25+Hp-75 and temperature 24±2°C triggered fast fecundity at approximately two days. The fecundity was low when based only on H. pluvialis (Hp), albeit with greater longevity (19 days) and a higher number of broods (8). D. birgei fed on Ag and Ag-75+Hp-25 diets in this experiment sustained higher growth rate and higher lipid content in these treatments. The present study showed that A. gracilis diet and mixed microalgae diets tested were able to support the egg production and development of D. birgei.

Ephemeroporus quasimodo sp. nov. (Crustacea: Cladocera: Chydoridae), a new species from the Brazilian Cerrado.

A new species of Chydoridae cladoceran (Crustacea: Cladocera: Chydoridae) is described from the Cerrado (a Brazilian tropical savanna ecoregion), Central Brazil. Ephemeroporus quasimodo sp. nov. differs from other species of the genus in a high dorsal keel on carapace and posterior part of the head shield, which resembles a hunchback. Parthenogenetic females, ephippial females and males are described, including details of trunk limb morphology. The species is endemic to shallow wetlands found in the Cerrado, where pristine conditions are preserved. Some questions on genus morphology and taxonomic status of Ephemeroporus species occurring in Brazil are discussed.

Alona iheringula Sinev & Kotov, 2004 (Crustacea, Anomopoda, Chydoridae, Aloninae): life cycle and DNA barcode with implications for the taxonomy of the Aloninae subfamily.

Knowledge of reproductive rates and life cycle of the Cladocera species is essential for population dynamic studies, secondary production and food webs, as well as the management and preservation of aquatic ecosystems. The present study aimed to understand the life cycle and growth of Alona iheringula Kotov & Sinev, 2004 (Crustacea, Anomopoda, Chydoridae), a Neotropical species, as well as its DNA barcoding, providing new information on the Aloninae taxonomy. The specimens were collected in the dammed portion of the Cabo Verde River (21°26'05″ S and 46°10'57″ W), in the Furnas Reservoir, Minas Gerais State, Brazil. Forty neonates were observed individually two or three times a day under controlled temperature (25±1°C), photoperiod (12 h light/12 h dark) and feeding (Pseudokirchneriella subcapitata at a concentration of 105 cells.mL-1 and a mixed suspension of yeast and fish feed in equal proportion). Individual body growth was measured daily under optical microscope using a micrometric grid and 40× magnification. The species had a mean size of 413(±29) µm, a maximum size of 510 µm and reached maturity at 3.24(±0.69) days of age. Mean fecundity was 2 eggs per female per brood and the mean number of eggs produced per female during the entire life cycle was 47.6(±6.3) eggs per female. The embryonic development time was 1.79(±0.23) days and the maximum longevity was 54 days. The species had eight instars throughout its life cycle and four instars between neonate and primipara stage. The present study using molecular data (a 461 bp smaller COI fragment) demonstrated a deep divergence in the Aloninae subfamily.

Growth and development time of subtropical Cladocera Diaphanosoma birgei Korinek, 1981 fed with different microalgal diets / Crescimento e tempo de desenvolvimento de uma espécie de Cladocera subtropical Diaphanosoma birgei Korinek, 1981 alimentada com dietas de microalgas.

The aim of this work was to investigate the growth performance of Diaphanosoma birgei fed with two Chlorophyceae algae, Ankistrodesmus gracilis and Haematococcus pluvialis using monoalgal diets and simpler mixed diets. D. birgei was daily fed on four treatments: 1) 100% Ankistrodesmus gracilis (Ag); 2) 100% Haematoccocus pluvialis (Hp); 3) 25% A. gracilis + 75% H. pluvialis (Ag-25+Hp-75) and 4) 75% A. gracilis + 25% H. pluvialis (Ag-75+Hp-25). The fecundity curve of D. birgei showed that the mixed feed Ag-25+Hp-75 and temperature 24±2°C triggered fast fecundity at approximately two days. The fecundity was low when based only on H. pluvialis (Hp), albeit with greater longevity (19 days) and a higher number of broods (8). D. birgei fed on Ag and Ag-75+Hp-25 diets in this experiment sustained higher growth rate and higher lipid content in these treatments. The present study showed that A. gracilis diet and mixed microalgae diets tested were able to support the egg production and development of D. birgei.

O objetivo deste estudo foi avaliar o crescimento de uma espécie de Cladocera Diaphanosoma birgei alimentada com dois tipos de microalgas Chlorophyceae, Ankistrodesmus gracilis e Haematococcus pluvialis cultivadas em monocultura e cultura mista. Quatro dietas foram utilizadas: 1) 100% Ankistrodesmus gracilis (Ag); 2) 100% Haematoccocus pluvialis (Hp); 3) cultura mista com 25% A. gracilis + 75% H. pluvialis (Ag-25+Hp-75) e 4) cultura mista com 75% A. gracilis + 25% H. pluvialis (Ag-75+Hp-25). A curva de fecundidade de D. birgei mostrou que a dieta mista Ag-25+Hp-75 e temperatura de 24±2°C promoveu rápida fecundidade em aproximadamente dois dias. A fecundidade foi baixa quando D. birgei foi alimentada somente com H. pluvialis (Hp), porém foi observada maior longevidade (19 dias) e consequentemente, maior número de descendentes (8). As dietas Ag and Ag-75+Hp-25 apresentaram efeito direto na taxa de crescimento de D. birgei com elevados teores de lipídios nestes tratamentos. O presente estudo mostrou que as dietas contendo somente A. gracilis e as dietas mistas de microalgas foram capazes de manter níveis adequados na produção de ovos e no desenvolvimento de D. birgei.

Growth and development time of subtropical Cladocera Diaphanosoma birgei Korinek, 1981 fed with different microalgal diets / Crescimento e tempo de desenvolvimento de uma espécie de Cladocera subtropical Diaphanosoma birgei Korinek, 1981 alimentada com dietas de microalgas

The aim of this work was to investigate the growth performance of Diaphanosoma birgei fed with two Chlorophyceae algae, Ankistrodesmus gracilis and Haematococcus pluvialis using monoalgal diets and simpler mixed diets. D. birgei was daily fed on four treatments: 1) 100% Ankistrodesmus gracilis (Ag); 2) 100% Haematoccocus pluvialis (Hp); 3) 25% A. gracilis + 75% H. pluvialis (Ag-25+Hp-75) and 4) 75% A. gracilis + 25% H. pluvialis (Ag-75+Hp-25). The fecundity curve of D. birgei showed that the mixed feed Ag-25+Hp-75 and temperature 24±2°C triggered fast fecundity at approximately two days. The fecundity was low when based only on H. pluvialis (Hp), albeit with greater longevity (19 days) and a higher number of broods (8). D. birgei fed on Ag and Ag-75+Hp-25 diets in this experiment sustained higher growth rate and higher lipid content in these treatments. The present study showed that A. gracilis diet and mixed microalgae diets tested were able to support the egg production and development of D. birgei.(AU)

O objetivo deste estudo foi avaliar o crescimento de uma espécie de Cladocera Diaphanosoma birgei alimentada com dois tipos de microalgas Chlorophyceae, Ankistrodesmus gracilis e Haematococcus pluvialis cultivadas em monocultura e cultura mista. Quatro dietas foram utilizadas: 1) 100% Ankistrodesmus gracilis (Ag); 2) 100% Haematoccocus pluvialis (Hp); 3) cultura mista com 25% A. gracilis + 75% H. pluvialis (Ag-25+Hp-75) e 4) cultura mista com 75% A. gracilis + 25% H. pluvialis (Ag-75+Hp-25). A curva de fecundidade de D. birgei mostrou que a dieta mista Ag-25+Hp-75 e temperatura de 24±2°C promoveu rápida fecundidade em aproximadamente dois dias. A fecundidade foi baixa quando D. birgei foi alimentada somente com H. pluvialis (Hp), porém foi observada maior longevidade (19 dias) e consequentemente, maior número de descendentes (8). As dietas Ag and Ag-75+Hp-25 apresentaram efeito direto na taxa de crescimento de D. birgei com elevados teores de lipídios nestes tratamentos. O presente estudo mostrou que as dietas contendo somente A. gracilis e as dietas mistas de microalgas foram capazes de manter níveis adequados na produção de ovos e no desenvolvimento de D. birgei.(AU)

Redescription of Alonella lineolata Sars, 1901 (Crustacea, Cladocera, Chydoridae) and its translocation to the subfamily Aloninae and to the new genus Bergamina gen. nov.

Alonella lineolata Sars 1901 (Anomopoda, Chydoridae) was described from a single female found in an aquarium prepared with dried mud from São Paulo, Brazil, and just recently this taxon has been reported again. The taxonomic status of A. lineolata was previously questioned, but re-evaluation was not possible until now due to the lack of specimens. The present paper described parthenogenetic females, based on specimens collected in a small pond at Prad6polis, state of São Paulo, and a specimen was selected as neotype. The head pores, mandibles, and the trunk limb morphology revealed that this species belongs to the subfamily Aloninae, instead of Chydorinae, as presumed by Sars. Despite its Alona-like aspect, this species presents a unique combination of characters, leading to its assignment to a new alonine genus, Bergamina gen. nov.

Micromoina arboricola n. gen., n. spec. (Crustacea: Cladocera), a new moinid living in a forest tree-hole in Minas Gerais, Brazil.

With a maximum size of ca 0.5 mm, Micromoina arboricola is among the smallest moinids known to date. It was discovered in a flooded treehole in a forest in the Medio Rio Doce Valley, Minas Gerais, Brazil, where it mainly feeds on particulate organic matter derived from the vinhatico tree . However, it is easily cultured in the lab on a diet of green algae plus yeast and pelleted fish food. Structurally, it is a miniature version of a moinid, distinguished by characters on the antennules (both sexes) and the postabdomen. The latter is peculiar in shape, in lacking a basal spine, and in having only three lateral plumose setae. A comparative investigation of the barcoding fragment of the COI gene in a number of moinids confirms the family Moinidae as composed of several genera, as well as the status of the new taxon.

Larvicidal activity of ajowan ( Trachyspermum ammi ) and Peru balsam ( Myroxylon pereira ) oils and blends of their constituents against mosquito, Aedes aegypti , acute toxicity on water flea, Daphnia magna , and aqueous residue.

This study evaluated the larvicidal activity of 20 plant essential oils and components from ajowan ( Trachyspermum ammi ) and Peru balsam ( Myroxylon pereira ) oils against the mosquito, Aedes aegypti . Of the 20 plant essential oils, ajowan and Peru balsam oils at 0.1 mg/mL exhibited 100 and 97.5% larval mortality, respectively. At this same concentration, the individual constituents, (+)-camphene, benzoic acid, thymol, carvacrol, benzyl benzonate, and benzyl trans-cinnamate, caused 100% mortality. The toxicity of blends of constituents identified in two active oils indicated that thymol and benzyl benzoate were major contributors to the larvicidal activity of the artificial blend. This study also tested the acute toxicity of these two active oils and their major constituents against the water flea, Daphnia magna . Peru balsam oil and benzyl trans-cinnamate were the most toxic to D. magna. Two days after the treatment, residues of ajowan and Peru balsalm oils in water were 36.2 and 85.1%, respectively. Less than 50% of benzyl trans-cinnamate and thymol were detected in the water at 2 days after treatment. The results show that the essential oils of ajowan and Peru balsam and some of their constituents have potential as botanical insecticides against Ae. aegypti mosquito larvae.