In 2005 and 2010, high sea surface temperatures caused widespread coral bleaching on Jamaica’s north coast reefs. Three shallow (9m) reef sites were surveyed during each event to quantify the prevalence and intensity of coral bleaching. In October 2005, 29-57% of the colonies surveyed were bleached. By April 2006, 10% of the corals remained pale/partially bleached. Similarly, in October 2010, 23-51% of corals surveyed at the same sites were bleached. By April 2011, 12% of the colonies remained pale/partially bleached. Follow-up surveys revealed low coral mortality following both events, with an overall mean of 4% partial colony mortality across all species and sites observed in April 2006, and 2% in April 2011. Mixed effects models were used to quantify the relationship between colony size and (a) bleaching intensity, and (b) bleaching related mortality among coral species. The bleaching intensity model explained 51% of the variance in the bleaching response observed during the two events. Of this 51%, fixed effects accounted for ~26% of the variance, 17% of which was attributed to species-specific susceptibility to bleaching , 5% to colony size, <1% colony morphology and 4% to the difference in bleaching intensity between the two events. The random factor (site) accounted for the remaining ~25% of the variance. The mortality model explained 16% of the variance in post bleaching mortality with fixed effects, including colony size, morphology and species explaining ~11% of the variance, and the random effect (site) explaining 5%. On average, there was a twofold difference in bleaching intensity between the smallest and the largest size classes. Modelling the relationship between colony level characteristics and site-specific environmental factors on coral species’ susceptibility to thermal stress can shed light on community level responses to future disturbances.

In 2005 and 2010, high sea surface temperatures caused widespread coral bleaching on Jamaica’s north coast reefs. Three shallow (9m) reef sites were surveyed during each event to quantify the prevalence and intensity of coral bleaching. In October 2005, 29-57% of the colonies surveyed were bleached. By April 2006, 10% of the corals remained pale/partially bleached. Similarly, in October 2010, 23-51% of corals surveyed at the same sites were bleached. By April 2011, 12% of the colonies remained pale/partially bleached. Follow-up surveys revealed low coral mortality following both events, with an overall mean of 4% partial colony mortality across all species and sites observed in April 2006, and 2% in April 2011. Mixed effects models were used to quantify the relationship between colony size and (a) bleaching intensity, and (b) bleaching related mortality among coral species. The bleaching intensity model explained 51% of the variance in the bleaching response observed during the two events. Of this 51%, fixed effects accounted for ~26% of the variance, 17% of which was attributed to species-specific susceptibility to bleaching , 5% to colony size, <1% colony morphology and 4% to the difference in bleaching intensity between the two events. The random factor (site) accounted for the remaining ~25% of the variance. The mortality model explained 16% of the variance in post bleaching mortality with fixed effects, including colony size, morphology and species explaining ~11% of the variance, and the random effect (site) explaining 5%. On average, there was a twofold difference in bleaching intensity between the smallest and the largest size classes. Modelling the relationship between colony level characteristics and site-specific environmental factors on coral species’ susceptibility to thermal stress can shed light on community level responses to future disturbances.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-10T18:55:49Z No. of bitstreams: 1 2012 - Gustavo Pena Freitas.pdf: 3480263 bytes, checksum: e0c63bdd4112e143bb273fe93d21ce6e (MD5) / Made available in DSpace on 2017-05-10T18:55:49Z (GMT). No. of bitstreams: 1 2012 - Gustavo Pena Freitas.pdf: 3480263 bytes, checksum: e0c63bdd4112e143bb273fe93d21ce6e (MD5) Previous issue date: 2012-02-29 / CAPES / This work aimed to study a population of Molossus molossus (Pallas , 1766) on Praia do Gato, llha de Itacuru??, Rio de Janeiro, analyzing aspects such as variation of colony size, use of roost, reproduction and activity. For this work 18 sampling nights were performed at intervals of 40 days between each month, between August 2009 and August 2011. Mist nets were opened near the access of two roosts, one in a house roof and another in a hollow of a tree. During the 25 sampling months, 689 captures and recaptures were done, and 309 individuals were marked. The number of captured and recaptured animals varied during the sample period, being inversely proportional to the duration of the night, with the months of November/2009 (88 individuals) and December/2009 (78 individuals) recording the highest number of catches. A decreasing number of individuals were observed in the second year of sampling as a possible consequence of the capture stress and/or the learning of the mist nets position by the bats. It was observed a greater number of transient individuals and a higher number of females throughout the study. In the roof was observed a greater number of young bats, possibly due to the higher temperature recorded. The bats performed exchanges between these two roosts throughout the year, being recorded 36 individuals performing exchanges, and the occurrence of 51 of such events. In relation to the reproduction, females had a monoestrous reproductive pattern, comprised between the months of November and January, with the males not showing a definite pattern. In relation to the activity period, the species showed a predominantly crepuscular pattern, with the females leaving the shelters earlier than the males, possibly due to increased energy demand. The animals spent an average of 36 minutes outside the roost, ingesting an average of 0.8 g of food, showing no difference throughout the year. / Este trabalho teve como objetivo geral realizar um estudo sobre uma popula??o de Molossus molossus (Pallas, 1766) na Praia do Gato na Ilha de Itacuru??, Rio de Janeiro, analisando aspectos como varia??o do tamanho da popula??o, uso dos abrigos, reprodu??o e atividade. Para o desenvolvimento deste trabalho foram realizadas 18 noites de amostragens com intervalos de aproximadamente 40 dias entre cada uma delas entre os meses de agosto de 2009 e agosto de 2011. Redes de neblina foram armadas pr?ximas as sa?das de dois ref?gios encontrados na praia, um em forro de uma resid?ncia e outro no oco de uma ?rvore. Durante os 25 meses de acompanhamento da col?nia, foram realizadas 689 capturas e recapturas, sendo marcados 309 indiv?duos. O n?mero de animais capturados e recapturados variou durante o per?odo de amostragem, sendo inversamente proporcional ? dura??o da noite, com os meses de novembro/2009 (88 indiv?duos) e dezembro/2009 (78 indiv?duos) registrando os maiores n?meros de capturas. Foi observado um decr?scimo no n?mero de indiv?duos no segundo ano de amostragem, como poss?vel consequ?ncia do estresse de captura e/ou do aprendizado pelos morcegos da posi??o das redes. Foram observados tamb?m um maior n?mero de indiv?duos transientes e um maior n?mero de f?meas, durante todo o trabalho. No forro da resid?ncia foi observado um maior n?mero de jovens, possivelmente em virtude da maior temperatura registrada. Os indiv?duos realizaram trocas entre esses dois abrigos durante todo o ano, sendo registrados 36 indiv?duos realizando trocas e a ocorr?ncia de 51 eventos desse tipo. Com rela??o ? reprodu??o, as f?meas apresentaram um padr?o reprodutivo mono?strico compreendido entre os meses de novembro e janeiro, com os machos n?o apresentando um padr?o sazonal definido. Com rela??o ao per?odo de atividade, a esp?cie apresentou um padr?o predominantemente crepuscular, com as f?meas saindo primeiro que os machos dos abrigos, possivelmente pela maior demanda energ?tica. Os animais gastaram em m?dia 36 minutos fora do abrigo, ingerindo em m?dia 0,8 gramas de alimento, n?o ocorrendo diferen?a ao longo do ano.

Measuring hormonal changes is vital for understanding how the social and physical environment influences behaviour, reproduction and survival. Various methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross validated to ensure they correlate. I directly compare faecal and plasma hormone measurements (Chapter 2), and use the most suitable endocrine measure to test the Darling hypothesis (Chapter 3) - that breeding is hastened and synchronized in larger colonies due to increased social stimulation (mediated by the endocrine system). Blood and faecal samples were simultaneously collected from individual Adelie penguins (Pygoscelis adeliae) for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher corticosterone levels than females, but the difference was only significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males; perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Faecal sampling appears more suitable for assessing baseline hormone levels. In the second study I examined, over two seasons, whether the timing of breeding varied with colony size; larger colonies present occupants with higher levels of social stimulation and are predicted to show earlier, more synchronous breeding. Baseline faecal hormone levels throughout the breeding season, and survival, were measured to investigate possible proximate and ultimate mechanisms for the results. The influence of environmental variability was examined, by relating the timing of breeding, survival, and endocrine changes to sea ice conditions. Colony size did not influence the timing or synchrony of breeding, survival, or hormone levels within years; perhaps because colonies in an Adelie rookery are not independent from the 'social environment' of adjacent colonies. Across years, synchrony in the smaller rookery was higher than in the larger rookery. The scale of these comparisons may exceed the applicability of the Darling hypothesis. Therefore, no support was found for the Darling hypothesis, at the colony or rookery level, in this species. Higher corticosterone metabolite and lower sex hormone levels in the first season correlated to later breeding and lower survival compared to the second season. This is likely due to the persistence of extensive sea ice conditions late into the first season. Researchers should take care in selecting the most appropriate method of hormone measurement for their question. Future studies testing the Darling hypothesis must carefully select their definition of a colony (i.e. a truly isolated social unit) and the scale at which the hypothesis is tested. Combining endocrine measurements with behavioural, survival, and environmental information allows for a more comprehensive interpretation of animal ecology.

Social insects are used as models for understanding the evolution of sociality because they show seemingly complex behavioral and physiological traits that enforce group cohesion, collective organization, and group level reproduction. Social organization in insect societies requires workers to share information. Information sharing allows workers to efficiently perform and switch among tasks to meet colony needs. For many species that nest in preformed cavities, colony growth results in crowding inside the nest which can affect colony productivity and fitness. How does colony size and social density affect individual and collective behavior? Using a combination of laboratory and field experiments, I have begun to answer this question. In Temnothorax rugatulus ants, high social density resulted in greater colony energy use. In addition, larger colonies used proportionally less energy compared to smaller colonies, but showed reduced brood production. These results indicate that the way colonies use energy changes with social density and group size. In analyzing the effects of colony size and density on worker behavior, I found that high density increased worker connectivity and information sharing. Workers in larger colonies showed less connectivity compared to workers in smaller colonies. Interestingly, workers with more interactions spent less time in brood care. This study shows that workers' access to information and the overall pattern of information flow are affected by social density and colony size, and changes in worker connectivity can influence task behavior. The next study shows that field colonies maintained a relatively constant level of intranidal density irrespective of colony size; this suggests that Temnothorax ants actively regulate social density. When colonies were established in high density nests, they showed greater foraging and scouting activities, and this led to a higher probability for becoming polydomous, i.e., occupying multiple nests. When polydomy occurred, colonies divided evenly between two nests, but distributed fewer, heavier workers and brood to the supplemental nests. Taken together, the first four studies indicate that social density is an important colony phenotype that affects individual and collective behavior and energetics in ants, and the collective management of social density may be a group adaptation in ants and other social insects. Lastly, because crowding affects polydomy behavior, the final two experiments tested whether colony emigration and nest construction and dispersion, two strategies for reducing intranidal crowding, are influenced by food distribution. Temnothorax colonies preferred to emigrate to nests positioned closer to food, and weaver ants (Oecophylla smaragdina) positioned newly constructed nests in food-rich areas. Furthermore, weaver ants used the newly constructed nests to more rapidly retrieve and safeguard valuable food items. Thus, strategic emigrations and adaptive nest dispersion can remedy intranidal crowding and at the same time allow growing colonies to acquire adequate food to meet colony needs.

Fungal infections of animals have become an increasingly important global issue. White-Nose Syndrome is an ongoing fungal epizootic of North American hibernating bats, caused by epidermal infections of the fungus, Pseudogymnoascus destructans. Infections emerged early in 2006 in New York State and have since spread to 35 US States and seven Canadian Provinces, with rates of mortality exceeding 90% in some bat colonies. As an emerging outbreak in North America, the transmission of P. destructans is assumed to occur in a radial fashion outwards from the point of origin. In addition, the factors that may influence P. destructans transmission have been postulated, but not tested before. Lastly, as reproduction is assumed to be strictly clonal in North America, invasive populations should have low genetic diversity, and may even accumulate deleterious mutations over time. The aim of my PhD research is to test these assumptions regarding the spread, evolution, and adaptation of P. destructans using combination of genotyping methods. My results showed how P. destructans isolates have shifted in terms of phenotypes and physiological capabilities since being introduced. In addition, I describe patterns of connectivity across the landscape, which are more consist with the level of anthropogenic activity than variation in climate. The mutations common to all invasive strains of P. destructans are associated with adaptations that have occurred since being introduced from Europe, some with relevant metabolic functions that fit their pathogenic lifestyle. Together, my results revealed significant phenotypic and genotypic changes during the spread of P. destructans in North America. The factors identified here that influence the phenotypic and genotypic changes should help developing better management strategies against the White-Nose Syndrome pathogen. / Thesis / Doctor of Philosophy (PhD)

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A populaÃÃo de abelhas vem declinando em todo mundo, e abelhas de grande porte, por necessitarem de maiores provimentos de alimento estÃo sendo mais afetadas pelas alteraÃÃes ambientais. Isso cria a necessidade de desenvolvermos alternativas e programas de conservaÃÃo para essas abelhas. AlteraÃÃes no tamanho corporal servem como indicativo desse declÃnio populacional. Dessa forma essa pesquisa teve como objetivo verificar mudanÃas no tamanho corporal das abelhas, principalmente nas abelhas de grande porte, como à o caso do gÃnero Bombus e desenvolver iniciativas de criatÃrio racional para conservaÃÃo da espÃcie nativa Bombus brevivillus gerando novas informaÃÃes à respeito dessa espÃcie que tem sido pouco estudada no Nordeste brasileiro. Dentre as milhares de espÃcimes presentes no Naturalis Museu, na Holanda, nÃs mensurados 4510, divididos em 18 espÃcies diferentes, aproximadamente 250 indivÃduos por espÃcie, entre machos e fÃmeas e distribuÃdos entre os anos de 1866 e 2013. NÃs tambÃm descrevemos o comportamento de nidificaÃÃo e as caracterÃsticas da colÃnia de B. brevivillus no estado do CearÃ, Brasil, e transferimos quatro colÃnias para caixas de madeira que permitiam o seu criatÃrio racional. NÃs obtemos informaÃÃes sobre os tipos polÃnicos utilizados, o padrÃo de forrageamento, a coleta de recursos, a influÃncia das variaÃÃes climÃticas nas atividades externas das operÃrias e sobre o desenvolvimento e estabelecimento das colÃnias em caixas racionais. Os resultados sugerem que 18 espÃcies de abelhas estudadas estÃo se tornando menores ao longo do tempo, sendo essa reduÃÃo no tamanho maior em fÃmeas de grande porte. Com relaÃÃo à abelha nativa B. brevivillus, as observaÃÃes mostraram que esta espÃcie parece ser oportunista em ralaÃÃo aos locais de nidificaÃÃo e proteÃÃo das crias e nÃo investe muito na construÃÃo do ninho e na proteÃÃo da prole. As colÃnias produziram um excelente nÃmero de operÃrias, que apresentaram, atà mesmo em caixas racionais, um intenso forrageamento e completaram seu ciclo normalmente, caracterÃsticas que podem ser Ãteis para fins de polinizaÃÃo comercial. / The bee population is declining around the world, and the big bodies bees, that require larger food provisions are particularly more affected by environmental changes. This creates the need to develop alternatives and conservation programs for these bees. Changes in body size are indicative of population decline. Thus, the objective of study was to verify the changes in body size of the bees, especially big bodied bees like the Bombus genus and develop rational breeding initiatives for conservation of native species Bombus (Thoracobombus) brevivillus generating new information about this species that is little studied in the Brazilian Northeast. We measured a total of 4510 specimens, of 18 different species, approximately 250 specimens per specie, equally divided over males and females and more or less regularly distributed over the entire study period (1866-2013). We also describe for the first time the nesting behavior and the colony of Bombus (Thoracobombus) brevivillus, and transferred four colonies to rational breeding boxes, to obtain information about pollen types used, foraging behavior, the resources collect, about the colonies development in rational breeding and the influence of climatic variations to the external activities of workers. Our results suggest that bees are becoming smaller over time, and larger species are more being more affected. About our native bumble bee B. brevivillus the observations showed that this specie seems to be opportunistic in relation to nesting sites and brood protection and does not invest much in nest building and offspring protection. Bombus brevivillus invest heavily in brood production and colony development, before producing reproductive individuals. Therefore, the colonies produce a great number of workers, a trait that could be useful for commercial pollination purposes.

No description available.

Characteristics of quantitative resistance in pea (Pisum sativum L.) to Erysiphe pisi DC, the pathogen causing powdery mildew, were investigated. Cultivars and seedlines of pea expressing quantitative resistance to E. pisi were identified and evaluated, by measuring the amounts of pathogen present on plant surfaces in field and glasshouse experiments. Disease severity on cv. Quantum was intermediate when compared with that on cv. Bolero (susceptible) and cv. Resal (resistant) in a field experiment. In glasshouse experiments, two groups of cultivars, one with a high degree of resistance and the other with nil to low degrees of resistance to E. pisi, were identified. This indicated either that a different mechanism of resistance applied in the two groups, or that there has been no previous selection for intermediate resistance. Several other cultivars expressing quantitative resistance were identified in a field experiment. Quantitative resistance in Quantum did not affect germination of E. pisi conidia, but reduced infection efficiency of conidia on this cultivar compared with cv. Pania (susceptible). Other epidemiological characteristics of quantitative resistance expression in Quantum relative to Pania were a 33% reduction in total conidium production and a 16% increase in time to maximum daily conidium production, both expressed on a colony area basis. In Bolero, the total conidium production was reduced relative to Pania, but the time to maximum spore production on a colony area basis was shorter. There were no differences between the cultivars in pathogen colony size or numbers of haustoria produced by the pathogen. Electron microscope studies suggested that haustoria in Quantum plants were smaller and less lobed than those in Pania plants and the surface area to volume ratios of the lobes and haustorial bodies were larger in Pania than in Quantum. The progress in time and spread in space of E. pisi was measured in field plots of cultivars Quantum, Pania and Bolero as disease severity (proportion of leaf area infected). Division of leaves (nodes) into three different age groups (young, medium, old) was necessary because of large variability in disease severity within plants. Disease severity on leaves at young nodes was less than 4% until the final assessment at 35 days after inoculation (dai). Exponential disease progress curves were fitted for leaves at medium nodes. Mean disease severity on medium nodes 12 dai was greatest (P<0.001) on Bolero and Pania (9.3 and 6.8% of leaf area infected respectively), and least on Quantum (1.6%). The mean disease relative growth rate was greatest (P<0.001) for Quantum, but was delayed compared to Pania and Bolero. Gompertz growth curves were fitted to disease progress data for leaves at old nodes. The asymptote was 78.2% of leaf area infected on Quantum, significantly lower (P<0.001) than on Bolero or Pania, which reached 100%. The point of inflection on Quantum occurred 22.8 dai, later (P<0.001) than on Pania (18.8 dai) and Bolero (18.3 dai), and the mean disease severity at the point of inflection was 28.8% for Quantum, less (P<0.00l) than on Pania (38.9%) or Bolero (38.5%). The average daily rates of increase in disease severity did not differ between the cultivars. Disease progress on Quantum was delayed compared with Pania and Bolero. Disease gradients from inoculum foci to 12 m were detected at early stages of the epidemic but the effects of background inoculum and the rate of disease progress were greater than the focus effect. Gradients flattened with time as the disease epidemic intensified, which was evident from the large isopathic rates (between 2.2 and 4.0 m d⁻¹) Some epidemiological variables expressed in controlled environments (low infection efficiency, low maximum daily spore production and long time to maximum spore production) that characterised quantitative resistance in Quantum were correlated with disease progress and spread in the field. These findings could be utilised in pea breeding programmes to identify parent lines from which quantitatively resistant progeny could be selected.