The aim of this study was to analyze the amount and the species composition of Daphnia gr. longispina resting egg bank in reservoirs. Studied reservoirs (Brno, Seč, Vír, Vranov a Žlutice) were sampled in July 2004 and 2005 at three sites {--} tributary, deep tributary and dam area. It was confirmed that there are more resting eggs at dam area than at tributary one and species composition differs for studied sites.

Orientador: Jorge Laço Portinho / Resumo: O objetivo deste estudo foi conhecer a distribuição de Cladocera na zona litorânea de lagoas marginais, abrangendo a comunidade de forma completa, incluindo suas formas ativa e dormente, encontradas nos habitats que compõem essa região: coluna d’água, sedimento e banco de macrófitas. O estudo foi realizado em quatro lagoas marginais. Em cada lagoa foram definidas quatro estações de amostragem, em cada estação foram amostrados os três habitats, sedimento e macrófita (comunidade dormente), e coluna d’água abaixo das macrófitas (comunidade ativa). Ao investigar essa organização, observamos que a comunidade de Cladocera se distribui de forma heterogênea entre os três habitats. O banco de ovos no sedimento apresenta maior riqueza de espécies e maior número de ovos, quando comparado ao banco de ovos nas macrófitas. A comunidade ativa e os bancos de ovos apresentam elevada interação em relação à deposição e eclosão de ovos. O sedimento e a coluna d’água são os principais habitats onde as espécies se distribuem, e embora apresentem elevada similaridade entre si (táxons em comum), esses habitats isoladamente não são capazes de representar de forma completa a composição e riqueza da comunidade de Cladocera da região litorânea, pois cada um apresenta táxons de ocorrência exclusiva. / Abstract: The objective of this study was to know the distribution of Cladocera in littoral area of marginal lagoons, covering the community completely, including its active and dormant forms found in the habitats that make up this area: macrophytes bank, sediment and water column. The study was carried out in four marginal lakes. In each lake four sampling stations were defined, in each station the three habitats were sampled, sediment and macrophyte (dormant egg banks), and water column below the macrophytes (active community). In investigating this organization, we observed that the community of Cladocera is distributed heterogeneously among the three habitats. The egg bank in the sediment presents higher species richness and higher egg numbers when compared to egg banks in macrophytes. The active community and the egg banks present high interaction in relation to resting eggs deposition and hatching. The sediment and the water column are the main habitats where the species are distributed, and although they have a high similarity between them (common taxa), these habitats alone are not able to fully represent the composition and richness of the community of Cladocera in littoral area, since each one presents taxa of exclusive occurrence. / Mestre

Parasites are thought to have large effects on their host populations, driving genetic change, population density changes, speciation and be a major selective force maintaining sexual reproduction. Indirect signatures of parasite-mediated selection are common, but explicit examples of parasite-mediated selection in nature are lacking. In this thesis I examine parasite-mediated dynamics in a natural population of Daphnia magna that experiences an annual epidemic of the bacterial pathogen Pasteuria ramosa. I also test a novel hypothesis investigating the relationship between parasitism and the production of resting eggs. In chapter 2 a combined field study and laboratory infection experiment illustrates one of the best examples of parasite-mediated selection in a natural population, with Daphnia collected after a parasite epidemic having higher levels of parasite resistance than those collected before. This chapter also explored the relationship between parasitism and resting eggs, which are only produced during the sexual phase of reproduction. Daphnia that were reproducing sexually in the field prior to the parasite epidemic were more susceptible, supporting higher levels of parasite growth, than their asexual counterparts. This supports the idea that some genotypes invest in sex at the expense of parasite resistance. In chapter 3 I used molecular markers to investigate genotype frequency changes in the same population in relation to the parasite epidemic. The parasite epidemic was found to be associated with genetic change in the population, and a laboratory infection experiment revealed that the genotype most resistant to the parasite was also most common following the peak of the parasite epidemic. While chapter 2 explored a genetic relationship between susceptibility and resting eggs, chapter 4 explores whether crowding conditions, cues indicating parasite prevalence in the population, or direct exposure to parasite spores can induce resting egg production. I found that crowding conditions or parasite prevalence enhance levels of male and resting egg production, but patterns were entirely dependent on Daphnia genotypes. There was no indication that exposure to parasite spores affects levels of sexual reproduction.

This thesis focused on the dynamics of the sexual reproduction of microcrustacean Daphnia (Cladocera, Anomopoda). Sex in Daphnia is induced environmentally after rounds of asexual parthenogenesis in favorable conditions. The onset of sexual reproduction and the occurrence of sexual individuals was investigated with respect to their distribution in the water column and clonal structure. The produced sexual eggs were genotyped and their density and distribution in sediment were analyzed. The impact of massive floods was investigated. The role of sexual reproduction in stable habitats and its relevance and importance for Daphnia communities is further discussed.

Submitted by WESLEY LUIZ GUIMARÃES null (wesleylg_33@hotmail.com) on 2016-03-29T18:16:06Z No. of bitstreams: 1 Dissertação Wesley.pdf: 1407502 bytes, checksum: 9130791fa2c390f3a21fc1a95500ec67 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-30T18:16:01Z (GMT) No. of bitstreams: 1 guimaraes_wl_me_sjrp.pdf: 1407502 bytes, checksum: 9130791fa2c390f3a21fc1a95500ec67 (MD5) / Made available in DSpace on 2016-03-30T18:16:01Z (GMT). No. of bitstreams: 1 guimaraes_wl_me_sjrp.pdf: 1407502 bytes, checksum: 9130791fa2c390f3a21fc1a95500ec67 (MD5) Previous issue date: 2016-03-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Planícies de inundação são áreas úmidas onde podem ser encontradas as lagoas marginais. Devido ao período de seca e a sua baixa profundidade, estas lagoas podem apresentar caráter temporário com ocorrência sazonal. Tal perturbação pode levar algumas populações zooplanctônicas, como as de cladóceros, a entrarem em estado de dormência, produzindo os ovos de resistência que se depositam no sedimento seco formando um banco de ovos. Quando as lagoas voltam a encher, a comunidade de cladóceros rapidamente se reestabelece, provavelmente como resultado da eclosão dos ovos presentes no sedimento. Detectar espécies de cladóceros que produzem os ovos de resistência como estratégia para recolonização, bem como os fatores que influenciam a eclosão dos ovos, pode auxiliar na compreensão do papel do banco de ovos como fonte de biodiversidade zooplanctônica em lagoas marginais. O objetivo neste estudo foi verificar o potencial de cladóceros para recolonização de lagoas marginais temporárias, por meio da eclosão de ovos de resistência em condições experimentais específicas. A comunidade zooplanctônica foi amostrada em quatro lagoas marginais localizadas na planície de inundação do Rio Turvo. As amostragens dos cladóceros planctônicos foram feitas com rede de plâncton de 50 μm de malha, antes e após um período de seca. Além disso, também foram medidos parâmetros físicos e químicos: profundidade, transparência, temperatura, pH, condutividade, OD, clorofila e material em suspensão. Para a realização dos experimentos de eclosão dos ovos de resistência em laboratório, amostras do sedimento das lagoas foram obtidas com Corer (4,5 cm de diâmetro), durante a estação seca. Duas metodologias foram testadas para indicar qual a mais eficaz para a eclosão: 1. Tratamento ambiente: frascos com sedimento e água do rio Turvo mantidos em condições ambiente; 2. Tratamento câmara: frascos com sedimento e água do rio Turvo mantidos em condições controladas em câmara de germinação (23ºC e fotoperíodo 12:12). A cada dois dias cada réplica foi analisada quanto aos parâmetros físicos e químicos e para a verificação de cladóceros recém eclodidos. Após duas semanas estes procedimentos foram realizados semanalmente até completar 60 dias. Uma porção do sedimento foi utilizada para a caracterização quanto à granulometria. Antes da seca 23 espécies estavam presentes nas lagoas estudadas, após a seca 16 espécies. Durante o experimento de eclosão o tratamento Câmara obteve 431 eclosões enquanto o tratamento Ambiente obteve 118. Houve a eclosão das espécies Alona glabra, Ephemeroporus hybridus, Ilyocryptus spinifer, Leydigiops ornata, Notoalona sculpta e Oxyurella longicaudis, destas eclodiram 6 e 4 espécies no tratamento Ambiente e Câmara, respectivamente. No tratamento Câmara, após 7 dias, E. hybridus foi a primeira espécie a eclodir, e no tratamento Ambiente após 9 dias eclodiram as espécies I. spinifer e N. sculpta. Com a análise da partição hierárquica verificou-se que no tratamento Câmara a condutividade e o pH apresentaram uma correlação positiva com a eclosão dos ovos de resistência e o oxigênio dissolvido uma correlação negativa. No tratamento Ambiente, os parâmetros condutividade e oxigênio dissolvido apresentaram uma correlação negativa com a eclosão dos ovos. Em conclusão pode-se apontar que as espécies da família Chydoridae e Ilyocryptidae, que são organismos bentônicos ou litorâneos, apresentam um maior potencial para rapidamente eclodir em ambientes lacustres temporários. / Floodplains are wetlands where the oxbow lakes can be found. Due of the dry season and its shallow depth, these lagoons can present seasonal occurrence. Such disruption can lead some zooplankton populations, such as cladocerans, to enter in dormancy, producing resting eggs that are deposited in dry sediment forming a bank of eggs. When the lagoons back to fill the cladoceran community quickly restores, probably as a result of the hatch of eggs present in the sediment. To detect species of cladocerans that produce resting eggs as a strategy for recolonization, as well as the factors influencing the eggs hatch, may help understanding the egg bank's role as zooplankton biodiversity source in lagoons. Our goal in this study was to investigate the potential of cladocerans to recolonize of temporary lagoons, through the hatching of resting eggs in specific experimental conditions. The zooplankton community was sampled in four lagoons located in the Turvo River floodplain. Sampling of planktonic cladocerans were taken by a plankton 50 µm mesh net before and after the drying lagoons. Physical and chemical parameters as depth, transparency, temperature, pH, conductivity, OD, chlorophyll and suspended material were also measured. For the hatching experiments of resting eggs in laboratory, sediment from lagoons were sampled using a corer (4.5 cm diameter), during the dry season. Two methods were tested to indicate the most effective for the hatching: 1. Environment Treatment: bottles with sediment and water from the Turvo river kept at ambient conditions; 2. Chamber Treatment: bottles with sediment and water from the Turvo river kept under controlled conditions in a growth chamber (23 ° C and photoperiod 12:12). Every two days each replica was analyzed for physical and chemical parameters and the verification of cladocerans newly hatched. After two weeks these procedures were performed weekly to complete 60 days. A portion of the sediment was used for particle size characterization. Before the drought 23 species were present in the studied lagoons, after drought 16 species. During the hatching experiment Chamber Treatment had 431 hatching while Environment Treatment had 118. Six species hatched: Alona glabra, Ephemeroporus hybridus, Ilyocryptus spinifer, Leydigiops ornata and Notoalona sculpta and Oxyurella longicaudis, being four species in the Chamber Treatment and six species in the Treatment Environment. In the Chamber Treatment, after 7 days, E. hybridus was the first species to hatch, and after 9 days Environment Treatment N. sculpta and I. spinifer hatched. With the analysis of hierarchical partition we found that in the Chamber Treatment conductivity and pH showed a positive correlation and dissolved oxygen a negative correlation with the hatching of resting eggs. In the Environment Treatment, conductivity and dissolved oxygen showed a negative correlation with the eggs hatch. In conclusion we can point that species of Chydoridae and Ilyocryptidae family, which are benthic or littoral organisms have a greater potential to quickly hatch into temporary lacustrine environments.

Diapause is often an adaptation for survival during periods of harsh environmental conditions. Some diapausing stages do not terminate the dormancy once the favourable conditions are restored. Such prolonged diapause may be enforced by environment if a diapausing stage cannot be reached by the cues inducing termination of dormancy. However, it may also be an advantageous bet-hedging strategy to allow only a fraction of dormant stages produced in any given season to hatch the next time conditions become favourable. I tested whether such strategy can be observed in hatching patterns of dormant eggs of Daphnia obtusa - a cladoceran occurring in small Central European temporary waters. I investigated the influence of intensity of illumination on hatching success, and effect of isolating the eggs encased in ephippia from the sediment. Fraction of eggs terminating diapause, fraction of embryos successfully leaving the egg membranes, and timing of the response were assessed at 15 ˚C under four intensities of illumination (100% = 35µmol.m2 .s-1 , 75%, 50%, 25%; photoperiod 12h light: 12h dark) and in complete darkness for 21 days. My results support previous suggestions that there is no genetically-fixed bet-hedging strategy in D. obtusa. I observed high proportion of eggs which terminated diapause in all...

The Tardigrada are hydrophilous, segmented, molting micrometazoans that occupy a diversity of niches in freshwater, marine, and terrestrial habitats. A sister group of the arthropods, this phylum of bilaterally symmetrical lobopods, most less than 1 mm in length, have a hemocoel, a complete digestive tract, a dorsal gonad with one or two gonoducts, and a dorsal lobed brain with a ventral nerve cord and five ganglia. About 1000 species have been described based on the morphology of sclerified structures, especially the claws and buccal-pharyngeal apparatus. Reproduction occurs through fertilized or unfertilized eggs, with individuals being either gonochoric, unisexual, or hermaphroditic, and eggs are deposited either freely or within the shed exuvium. Parthenogenesis, very frequent in limnic and terrestrial tardigrades, allows them to colonize new territories by passive dispersal of a single individual. Quiescence (cryptobiosis: anhydrobiosis, anoxybiosis, cryobiosis, and osmobiosis) and diapause (encystment and resting eggs) occur during the tardigrade life history. Ecological parameters and global distribution patterns are poorly known or understood. Methods for collection, microscopy, and culturing have been developed.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-31T15:37:55Z No. of bitstreams: 1 lucianarabelodearaujo.pdf: 3777751 bytes, checksum: f71885f2bbf7188c5613e7ece870e07f (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: primeira letra de cada palavra chave em maiúsculo on 2016-07-02T12:46:13Z (GMT) / Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-04T10:27:45Z No. of bitstreams: 1 lucianarabelodearaujo.pdf: 3777751 bytes, checksum: f71885f2bbf7188c5613e7ece870e07f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:13:25Z (GMT) No. of bitstreams: 1 lucianarabelodearaujo.pdf: 3777751 bytes, checksum: f71885f2bbf7188c5613e7ece870e07f (MD5) / Made available in DSpace on 2016-07-13T16:13:25Z (GMT). No. of bitstreams: 1 lucianarabelodearaujo.pdf: 3777751 bytes, checksum: f71885f2bbf7188c5613e7ece870e07f (MD5) Previous issue date: 2012-02-27 / Poças adjacentes em ambientes aquáticos costeiros podem servir como refúgio para organismos em condições ambientais desfavoráveis, desde que haja conexão hidrológica entre os sistemas. Neste trabalho, foram avaliados os fatores estruturadores e a importância da hidroconectividade para comunidades zooplanctônicas de 3 lagoas salinas e 15 poças adjacentes localizadas em Quissamã/RJ, e o papel do banco de ovos de resistência na recolonização de uma lagoa costeira. Amostras da comunidade e das variáveis ambientais foram coletadas no período de um ano (Maio 2010 – Fevereiro 2011) e o banco de ovos foi coletado em agosto de 2010 no sistema Garça. Através de uma NMS utilizando o índice de similaridade de Bray-Curtis, as poças mostraram ser mais similares entre si do que com as lagoas, independente do período (seca ou chuva). Uma RDA mostrou que a salinidade e o pH foram os principais fatores estruturadores das comunidades. O cálculo da diversidade beta evidenciou que as poças apresentaram uma menor turnover temporal. No sistema Garça, as poças apresentaram bancos de ovos mais ricos que a lagoa, e 45% das espécies registradas na comunidade ativa da lagoa foram registradas exclusivamente nas poças. Embora as lagoas e suas poças não tenham sido mais similares no período chuvoso, a conectividade parece ter uma grande importância, devido à presença de espécies dulcícolas nas lagoas nos períodos mais chuvosos, encontradas também nas poças. Este fato, além da menor diversidade beta exibida pelas poças sugere que a dispersão não é limitante, possivelmente formando uma metacomunidade. A alta contribuição da comunidade ativa e dormente das poças para a comunidade ativa da lagoa da Garça mostra o potencial destes ambientes na manutenção e recolonização da comunidade zooplanctônica deste sistema. / Small-sized pools next to coastal lakes may serve as refuge for organisms during unfavorable environmental conditions in the lakes, due to sporadic connections between all aquatic systems. We assessed the importance of environmental variables and of the hydrological connectivity for the structure of zooplankton communities in three saline lagoons and 15 adjacent pools from Brazil. We also evaluated the role of the resting egg bank in the recolonization of the zooplankton community in one coastal lagoon. Zooplankton and environmental variables were collected during one year (2010–2011) and the resting egg bank was collected in August 2010 in the Garça system. NMS analyses using a Bray-Curtis index showed that the pools were more similar between each other than between the lagoons, regardless of the season (dry or rainy). A RDA showed that salinity and pH were the main structuring factors of communities in all lagoon systems. The beta-diversity index demonstrated that the lagoons had a higher temporal turnover. In the Garça system, the pools showed richer egg banks than the lagoon and 45% of the species recorded in the lake’s active community were founded in the pools. Although lagoons and pools were not more similar in the rainy season, the connectivity seems to have a major role due to the presence of freshwater species in the lakes, that were also found in the pools. This fact, plus the lower beta diversity showed by pools suggest that dispersal is not limited. The high contribution of the active and dormant communities of the pools for Garça lake’s active community shows the potential of these environments in the maintenance and recolonization of zooplankton community in this system.

A sister group of the Arthropoda, the Tardigrada are micrometazoans that occupy a diversity of niches in freshwater, marine, and terrestrial habitats. Commonly called water bears because of their slow, lumbering gait, these molting lobopods have four pairs of legs, usually terminating in claws. Most are less than 1 mm in length, with a complete digestive tract, a dorsal gonad with one or two gonoducts, and a dorsal lobed brain with a ventral nerve cord and four bilobed ganglia, one per leg-bearing metamere. The body cavity (hemocoel) functions in respiration and circulation. Over 1200 species have been described based primarily on the morphology of the claws and buccal-pharyngeal apparatus. Individuals may be either gonochoric, unisexual, or hermaphroditic, with fertilized or unfertilized eggs deposited either freely or within the shed exuvium. Parthenogenesis occurs frequently in limnic and terrestrial tardigrades, allowing them to colonize new territories by passive dispersal of a single individual. Cryptobiosis (anhydrobiosis, anoxybiosis, cryobiosis, and osmobiosis) and diapause (encystment and resting eggs) occur during the life history. Active adults (surrounded by water) and cryptobiotic adults and eggs are primarily dispersed passively, but some active dispersal can also occur. Due to the characteristic patchy distributions of tardigrade populations, little is known about their population dynamics and trophic relationships. Improved methods for collection, microscopy, culturing, and molecular analyses have been have contributed much to our knowledge of tardigrades.