The knowledge of population dynamics allows us to study the variations in the abundance of populations of living beings. Knowledge of the abundance of ticks that parasitize lactating cattle in a given region is important when considering the direct damage that these ectoparasites cause and their ability to transmit pathogens to animals. The aim of the present study was to characterize the population dynamics of Rhipicephalus microplus in naturally infested mestizo dairy cattle maintained in a rotational grazing system for 12 months in a semi - humid tropical region in the state of Goiás. the selected cattle had the female ticks counted (4.5 to 8.0 mm). A flannel-dragging technique was also carried out in the pasture for the capture and subsequent counting of R. microplus larvae. The meteorological data were collected during the study to be used in regression and variance analyzes. Based on the experimental design used, it was possible to observe the increase in the number of tick generations during the experiment, for five generations during the year. It was also observed that the climatic variables such as humidity, temperature and rainfall had a direct relation with the amount of larvae present in the pasture (P> 0.05). The number of larvae present in pastures presented significant negative correlation (P≤0.05) with rainfall (P = 0.0001), ambient temperature (P = 0.0005) and relative humidity (P = 0.0120). On the other hand, the average parthenogenic counts in the animals' body did not show a significant correlation (P> 0.05) with the climatological parameters. In summary, it was possible to verify the presence of five generations / year of R. microplus in the tropical semi-humid region, besides the influence of the climatic variables on the non-parasitic phase of the bovine tick. These results are related to the biological, ecological, population and behavioral aspects of R. microplus, allowing us to help map an epidemiological profile in the region and to define future strategies for the management and control of this ectoparasite of cattle.

Limnomedusa macroglossa é única espécie pertencente ao gênero Limnomedusa (Alsodidae), e é distribuida pelo sul do Brasil, Uruguai e partes da Argentina e Paraguai. L. macroglossa é um anuro associado a riachos pedregosos em áreas florestais e campestres, com girinos que ocorrem em diferentes microhabitats no leito dos riachos com morfologia externa brevemente descrita na década de oitenta. Muitas Informações sobre a morfologia externa, bem como variação individual devido a fatores intrínsecos e extrínsecos permanecem ainda inexplorados. Assim, este trabalho tem como objetivos: (1) redescrever a morfologia externa do girino de Limnomedusa macroglossa; (2) analisar a variação na forma dos indivíduos (em vista dorsal e lateral); (3) verificar se o tamanho dos indivíduos (alometria) e a profundidade dos riachos interferem na forma. Os girinos foram coletados em 13 riachos distribuídos na Área de Proteção Ambiental do Ibirapuitã e áreas adjacentes, na divisa entre Rio Grande do Sul e Uruguai. A redescrição foi baseada em 20 girinos entre os estágios 31 e 37, analisando 57 e 19 caracteres qualitativos e quantitativos, respectivamente. Para as análises morfométricas foram fotografados 150 girinos entre os estágios 30 e 37. Com base nas fotos, foram digitalizados 17 marcos anatômicos na vista lateral e 15 na vista dorsal. A caracterização morfológica apresentada no presente estudo diferiu daquela previamente reportada, principalmente quanto aos seguintes aspectos: coloração, forma do corpo, narinas, tubo anal, cauda, formato e posição das narinas e focinho. Foram adicionados caracteres inéditos referentes ao espiráculo, tubo anal, nadadeiras e disco oral. Apesar da variação morfológica ser resultado de forças evolutivas e ser utilizada para reconstruir relações filogenéticas, girinos de L. macroglossa não apresentaram marcada semelhança com girinos dos outros dois gêneros da família Alsodidae (Eupsophus e Alsodes), o que possivelmente está relacionado com as relações filogenéticas mal resolvidas para esse grupo até o momento. Dentre os demais aspectos discutidos, sugerimos a reclassificação do modo reprodutivo de L. macroglossa, como forma de melhor refletir a associação dos girinos com ecossistemas lóticos e as respectivas adaptações morfológicas relacionadas a hábitos reofílicos facultativos. A alometria foi um fator que afetou a forma do girino em vista lateral, influenciando principalmente a forma do corpo, bem como a posição dos olhos e narinas, estruturas que reconhecidamente sofrem mudanças ao longo do desenvolvimento larval em direção à metamorfose. O gradiente ambiental de profundidade dos riachos também foi responsável por uma pequena parte da variação encontrada na forma dos girinos de L. macroglossa. Em ambientes de menor profundidade os girinos apresentam uma diminuição na altura geral do corpo, das nadadeiras e da musculatura da cauda em vista lateral enquanto um aumento da largura do corpo foi verificado em vista dorsal. Estas variações na forma sugerem possíveis adaptações para viabilizar o deslocamento do animal de maneira eficiente em ambientes de alta energia (i.e. com fluxo d’água mais intenso).

O objetivo do presente estudo foi observar os efeitos climáticos sobre a infestação de larvas infectantes na pastagem nativa nos períodos de primavera e verão e a correlação com a dinâmica de parasitismo gastrintestinal em borregas naturalmente infectadas. O experimento foi realizado entre outubro de 2013 a março de 2014 em propriedade particular no interior do município de Dom Pedrito – RS com 50 borregas da raça Corriedale e peso médio inicial de 28 kg em um potreiro de nove hectares de campo nativo sem divisões. Em intervalos de 21 dias foram avaliados nos animais o escore da condição corporal (ECC), contagem de ovos por gramas de fezes (OPG), coprocultura e FAMACHA®. Realizaram-se mensurações para verificar a altura da pastagem (cm), coleta da mesma para recuperação de larvas infectantes (L3) e disponibilidade de pasto (kg/MS/ha), além de ser observada precipitação (mm), temperatura (°C), radiação solar (KJ/m²) e umidade relativa do ar (%). Os animais foram vermifugados conforme a necessidade de acordo com o grau de infecção parasitária. Observou-se ao término do período experimental que OPG maior que 500 impactou em menor ganho de peso (2,03kg) (p=0,000), FAMACHA >3 (p=0,005) e ECC <3 (p=0,027) no verão com diferença significativa em relação a primavera. Em relação à coprocultura pode-se observar maior prevalência do gênero Haemonchus spp. (72,79%) durante todo o período experimental. Foi possível verificar a relação entre o OPG e recuperação de larvas infectantes da pastagem com os dados climáticos, constatando diferença significativa para OPG (>500) e maior quantidade de L3 recuperadas (>19,17 L3/kg/MS) em temperatura acima de 22,5 °C (p=0,000), verão (p=0,000), precipitação >120 mm (p=0,003), umidade relativa >73% (p=0,005) e radiação solar <890 KJ/m² (p=0,000). Observou-se diferença significativa entre o OPG e disponibilidade de pasto >2,600 kg/MS/ha e altura da pastagem >14,5 cm (p=0,000). Foi observada diferença significativa de OPG >500 em relação a quantidade de larvas na pastagem (>19,17 L3/kg/MS) (p=0,000). Os fatores climáticos podem influenciar no desenvolvimento de larvas infectantes no pasto, favorecendo a maior ingestão e consequentemente maior carga parasitária nos animais. As borregas não conseguiram alcançar o peso mínimo e escore da condição corporal para o período reprodutivo provavelmente influenciado pelo parasitismo gastrintestinal durante o verão. Tornam-se necessários a continuidade dos estudos nesta área para melhor compreender a dinâmica de larvas infectantes nas pastagens naturais.

Wolbachia is one of the most prevalent bacterial endosymbionts, infecting approximately 40% of terrestrial arthropod species. Wolbachia is often a reproductive parasite but can also provide fitness benefits to its host, as, for example, protection against viral pathogens. This protective effect is currently being applied to fight arboviruses transmission by releasing Wolbachia-transinfected mosquitoes. Titre regulation is a crucial aspect of Wolbachia biology. Higher titres can lead to stronger phenotypes and fidelity of transmission but can have a higher cost to the host. Since Wolbachia is maternally transmitted, its fitness depends on host fitness, and, therefore, its cost to the host may be under selection. Understanding how Wolbachia titres are regulated and other aspects of Wolbachia biology has been hampered by the lack of genetic tools. Here we developed a forward genetic screen to identify new Wolbachia over-proliferative mutant variants. We characterized in detail two new mutants, wMelPop2 and wMelOctoless, and show that the amplification or loss of the Octomom genomic region lead to over-proliferation. These results confirm previous data and expand on the complex role of this genomic region in the control of Wolbachia proliferation. Both new mutants shorten the host lifespan and increase antiviral protection. Moreover, we show that Wolbachia proliferation rate in Drosophila melanogaster depends on the interaction between Octomom copy number, the host developmental stage, and temperature. Our analysis also suggests that the life shortening and antiviral protection phenotypes of Wolbachia are dependent on different, but related, properties of the endosymbiont; the rate of proliferation and the titres near the time of infection, respectively. We also demonstrate the feasibility of a novel and unbiased experimental approach to study Wolbachia biology, which could be further adapted to characterize other genetically intractable bacterial endosymbionts.

Climate change has pervasive effects on marine ecosystems, altering biodiversity patterns, abundance and distribution of species, biological interactions, phenology, and organisms' physiology, performance and fitness. Fish early life stages have narrow thermal windows and are thus more vulnerable to further changes in water temperature. The aim of this study was to address the sensitivity and underlying molecular changes of larvae of a key fisheries species, the sea bream Sparus aurata, towards ocean warming. Larvae were exposed to three temperatures: 18°C (control), 24°C (warm) and 30°C (heat wave) for seven days. At the end of the assay, i) survival curves were plotted for each temperature treatment and ii) entire larvae were collected for proteomic analysis via 2D gel electrophoresis, image analysis and mass spectrometry. Survival decreased with increasing temperature, with no larvae surviving at 30°C. Therefore, proteomic analysis was only carried out for 18°C and 24°C. Larvae up-regulated protein folding and degradation, cytoskeletal re-organization, transcriptional regulation and the growth hormone while mostly down-regulating cargo transporting and porphyrin metabolism upon exposure to heat stress. No changes were detected in proteins related to energetic metabolism suggesting that larval fish may not have the energetic plasticity needed to sustain cellular protection in the long-term. These results indicate that despite proteome modulation, S. aurata larvae do not seem able to fully acclimate to higher temperatures as shown by the low survival rates. Consequently, elevated temperatures seem to have bottleneck effects during fish early life stages, and future ocean warming can potentially compromise recruitment's success of key fisheries species.

Physical processes that force transport of planktonic larvae of invertebrates are responsible for some of the spatial and temporal variability in recruitment. We investigated the influence of tide- and winddriven circulation on intra-year variability of megalopal supply to populations of the crab Carcinus maenas in 2 estuaries on the Portuguese west coast. Daily data on physical variables and on supply and settlement of megalopae were subjected to time series analysis and multiple regression techniques in order to identify periodicity in the variables as well as time lags between larval supply and physical variables. Relaxation of northerly winds, which favor upwelling, was associated with temperature increase and subtidal sea level rise at the coast, which are indicative of coastal convergence of the surface layer. Supply of megalopae to the estuaries, as measured with passive plankton nets, followed a fortnightly cycle with maximum larval supply at the time of maximum tidal amplitude. Supply was enhanced by southerly winds, with delays of 0 to –2 d. Settlement of megalopae on artificial settlement substrates deployed on the bottom was uncoupled to supply at both estuaries. Therefore, transport of C. maenas megalopae to the nearshore is accomplished by onshore advection following downwelling winds, and supply to the estuaries occurs by selective tidal stream transport. Involvement of internal waves and internal tidal bores cannot be be ruled out, but very particular periodicities of the generating mechanisms would have to be assumed to account for the observed time lags.

Viral infections in aquaculture are one of the main obstacles to aquaculture development, as they cause high economic losses. Viral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), significantly impacts marine and freshwater aquaculture, causing high mortality in larval and juvenile populations with mortality rates up to 100%. There is no effective treatment against this infection nor commercial vaccine development. This study aimed to assess the applicability of a polyclonal antibody with antiviral potential for supplementing the diet of European seabass (Dicentrarchus labrax) in the larval stage after contact with NNV of the RGNNV genotype, as well as to evaluate how this antibody treatment could influence both fish survival rates and the reduction of viral replication over time. A neutralisation protocol was established using rabbit anti-NNV polyclonal antibodies as a positive control. Results demonstrate that PAb can be effectively administered to fish through both immersion and dietary routes, with findings suggesting potential protective effects when delivered via the diet. It was found that NNV infection is more efficient via injection (20%) compared to immersion (0%). Mortality was monitored and analysed throughout the trial, along with viral load, to gain a comprehensive understanding of the potential benefits associated with the administration of this polyclonal antibody following NNV infection. A reduction in mortality was observed in the treatment in which the feed was supplemented with rabbit serum (33.2%) compared to the treatment where the fish were infected with NNV (41.7%). A reduction in viral load was also observed between these treatments. Thus, supplementation with antiviral immunostimulants could be a promising strategy to prevent irreversible damage. However, more studies are still needed to understand how the immune system works in the presence of NNV with subsequent supplementation with polyclonal antibodies.

Little is known about the early development stages of Parablennius ruber. In this paper the following stages are described, and illustrations provided for the first time: middle stage egg, late stage egg, yolk-sac larva and preflexion larva. Recently laid eggs were spherical and orange, attached to the substratum in rock crevices. Eggs measured 1.02 mm in diameter. Newly hatched larva measured 4.65 mm total length and had the mouth closed and the anus open, fully pigmented eyes and a big yolk sac. Pectoral fins were present, rounded and not radially pigmented. Yolk was absorbed in 2–3 days at room temperature. Preflexion larvae had pointed pectoral fins, bigger eyes, well developed lips and strong jaws. Operculae were open. Orange chromatophores began to be noticeable between the eyes.

Wind-driven circulation is a mechanism that may be involved in the shoreward transport of invertebrate larvae. This study investigated the temporal variability of the supply of crab megalopae to an estuary located in the northwest coast of Portugal, which is affected by seasonal upwelling, and related variations in supply to several upwelling indices. Megalopae of the European common shore crab Carcinus maenas (L.). were collected daily, using artificial settlement substrates, during a 3-month period, from March 15 to June 15, 2000. Two settlement episodes were detected, which were consistent with the variation in abundance and size of juvenile crabs. Variations in subtidal sea level and sea surface temperature anomaly were correlated with the strength of along-shore wind stress and consistent with upwelling theory. Contingency analyses showed positive significant associations between increasing intensity of southerly winds and megalopal supply, for time lags of 0–6 d, indicating that shoreward transport occurred during relaxation or reversal of upwelling favourable winds. Associations between megalopal supply and tidal range or the duration of nocturnal flood were not detected. Compared to other studies of the supply of crab megalopae to coastal habitats that used a similar methodology, very low numbers of megalopae were collected during this study. The paucity of C. maenas megalopae in the Ria de Aveiro is in agreement with the low densities of this larval stage in the plankton, and indicates that maintenance of the population is achieved despite a low supply of megalopae.

The effect of low salinity on the survival of recently hatched veliger of the gastropod Nassarius reticulatus (L.) was studied under laboratory conditions at 17 °C ± 1 °C. Significant mortality occurred for salinities ≤ 17 psu and the LS50 (salinity that causes 50% mortality) varied from 14.5 psu to 17.2 psu for exposures between 1 h and 48 h, respectively. The results were included in a mathematical model in order to estimate the mortality of N. reticulatus veliger in Ria de Aveiro under different salinity scenarios determined by numerical simulation. The model predicts a massive mortality of veliger immediately after their eclosion (1 h) in Ria de Aveiro during spring tide when the river input reaches its expected maximum — a situation that has been observed occasionally and may overlap a massive eclosion of veliger in the water. Except in this extreme situation, the mortality in Ria de Aveiro is generally restricted to the upstream limits of the channels. The results indicate that N. reticulatus recruitment in estuaries may strongly depend on the prevailing salinity regime.