Master of Science / Department of Entomology / Srinivas Kambhampati / Termites (Isoptera) are eusocial insects and exhibit highly complex eusocial behavior. Eusociality is characterized by the presence of castes (workers, soldiers, reproductives), polyphenisms (same genotype exhibiting multiple phenotypes), flexible developmental pathways, complex communication, cooperative brood care, construction and maintenance of complex nests, and division of labor. Previous studies on honey bees implicated several genes in caste-specific behavior; here, we investigate if orthologs of such genes are present in termites and if so, whether they are expressed differentially among the castes. A candidate gene approach using degenerate primers was used to amplify three candidate genes in the termite Reticulitermes flavipes. Quantitative real time PCR analysis revealed differential expression among termite workers, soldiers, and alates, with a general pattern of higher expression in alates. These results provide information on three novel genes in the termite R. flavipes.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2006. / The role of the southern harvester termite, Microhodotermes viator, and several climatic parameters in the distribution of the group-living lizard, Cordylus cataphractus, was investigated. Microhodotermes viator is considered the most important prey item of C. cataphractus and termitophagy as the causative agent in the evolution of group-living in this species. One would therefore expect a high degree of correspondence in the ranges of C. cataphractus and M. viator. As climate will also play a role in the distribution of any species, various climatic variables were investigated to determine their influence on the distribution of C. cataphractus. Species distributions were visualized using the minimum polygon technique and the degree of overlap was determined using standard geographic information systems (GIS) techniques. A total of 53 C. cataphractus localities were investigated for the presence of termites. The climatic limits of the geographical distribution of C. cataphractus were investigated by means of three models, namely Classification Trees, General Discriminant Analysis and Logistic Regression. The range of C. cataphractus was completely included within the range of M. viator Microhodotermes viator was included in the diet of C. cataphractus at 73 % of the localities sampled within the lizard’s range. The current geographical range of C. cataphractus is mainly correlated with two climatic factors, namely the low summer rainfall and high monthly solar radiation. The restricting role of both these factors can be directly linked to the group-living nature of C. cataphractus. If termitophagy were the overarching cause of group-living in C. cataphractus, then one would expect a close relationship between termite density and lizard density and termite density and lizard group size. I investigated these relationships at both a local and regional scale. For the local scale study, 25 quadrats of 25 × 25 m were plotted at a selected site, and for the regional scale study, ten 35 × 35 m quadrats at sites throughout the lizard’s range were used. In each quadrat, a range of variables were recorded, the most important of which were lizard density, lizard group sizes, termite foraging port density, distance to nearest termite foraging ports, vegetation height and vegetation cover. I found that the density of termite foraging ports determines C. cataphractus density. Vegetation height and cover affects crevice selection by C. cataphractus groups, probably because an unobstructed view is necessary to locate termite activity at foraging ports. I also investigated possible differences in the use of termites by different sized groups of C. cataphractus during different times of the year. Faecal samples, collected once a month at Eland’s Bay from small, medium and large groups from January 2005 to December 2005, were analysed for the presence of termite head material. I found that large groups fed on termites to a greater extent than small groups during certain times of the year and there was a general tendency for this phenomenon throughout the year. The results collected in this study indicate that the southern harvester termite, M. viator, plays a central role in the ecology of the group-living lizard, C. cataphractus.

African elephants are ‘keystone’ species with respect to biodiversity conservation in Africa since they maintain habitats that support several animal communities by changing vegetation structure through foraging and by dispersing seeds between landscapes. Elephants are also ‘flagship’ species because, given their impressive size, they can make people sympathetic and stimulate local and international concerns for their protection. Economically, elephants contribute to national revenues as tourists are willing to pay to watch them. Despite all these factors, little is known however about elephant movement and how they utilize resources, especially in miombo-wetland ecosystems. This thesis investigates how elephants utilize resources in a miombo-wetland ecosystem in the Ugalla landscape of Western Tanzania over different protected areas containing different resource users. Using Global Positioning System (GPS) collars fitted to six elephants, it was observed that some elephant families are not confined in one protected area in the Ugalla landscape. Rather, they moved readily between different protected areas. Elephant movements were restricted to areas near the rivers, especially the Ugalla River, during the dry season and were dispersed widely during the wet season. As they move, elephants in the miombo woodlands of Ugalla selected the most abundant woody plants for browsing. Common to many woody plants, the browsed plants were short of mineral nutrients (e.g., sodium, calcium). Elephants obtained additional minerals by eating soils from certain termite mounds. Soils from termite mounds are richer in mineral elements (e.g., sodium, calcium, iron) compared to soils from the surrounding flood plain or compared to the browsed plants. However, the recorded termite mounds from which elephants eat soils were not evenly distributed in the landscape but confined mainly to the flood plains in the Ugalla Game Reserve. The Ugalla River, which is the main source of water for the elephants and other animals and also supports fishing activities by the local people in Ugalla during the dry seasons, is infested by the water hyacinth (Eichhornia crassipes). Such infestation potentially limits access to these precious surface water supplies. In addition at the regional level, the Ugalla River is among the major rivers that flow into the Lake Tanganyika which is shared by the countries of Tanzania, Burundi, Democratic Republic of Congo and Zambia. Thus, the spread of water hyacinth if left unchecked threatens to impact Lake Tanganyika, affecting many countries and ecosystem services. This thesis highlights that sustainable conservation of biodiversity in different protected areas in the Ugalla landscape requires an integrated management approach that will embrace conservation of different interrelated landscape resources required by both wildlife and the rural poor populations for their livelihoods. Regular coordinated wildlife anti-poaching patrols should be initiated across the entire Ugalla landscape because the elephants, among other wildlife, utilize different protected areas in Ugalla. Local communities should also be engaged in conservation initiatives (e.g., controlling the spread of the water hyacinth) as these directly impact local livelihoods. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p> / INTEGRATED NATURAL RESOURCES MANAGEMENT

Termites are important ecosystem engineers in tropical and sub-tropical terrestrial regions where they influence ecosystem processes by altering the physical and chemical structure of the habitat. Termites affect nutrient availability by decomposition and comminution (shredding) of organic matter and act as agents of bioturbation as they re-work substrates during the construction of nests, tunnels and runways. At present we have a relatively good understanding of termite diversity patterns in the tropics through the extensive use of the standardised transect sampling protocol by Eggleton et al. (1995). These diversity data suggest that there is a functional difference in termite assemblage structure, and potentially in termite abundance and biomass, among comparable habitats across continents. However due to the lack of comparable abundance and biomass data from South America this has not previously been confirmed. In this thesis I, therefore, collected extensive data on termite taxonomic and functional assemblage structure in a South American site in Peru. The data were used to compare termite abundance and biomass from two comparable sites in Africa (Cameroon) and south east Asia (Malaysia) in order to gain better understanding of the role termites play in ecosystem processes. I found that there was an intercontinental difference in the abundance and biomass of termite feeding-groups mainly due to the dominance of soil-feeding termites in Cameroon and the absence of fungus-growing termites from Peru. The impact of certain lineages on the intercontinental differences suggests that the differences may be due to biogeographical evolution. Moreover, Eggleton et al. (1998) show that larger-bodied soil-feeding termites in Cameroon process more energy per unit area than predicted by their body size. Due to the need for an examination of the allometric relationships in termite assemblages outside Africa and the development of a more sophisticated feeding-group classification I explore the findings in Eggleton et al. (1998) further using population density - body mass relationships in three termite feeding-groups among the three continental sites in Cameroon, Peru and Malaysia. I found that large-bodied soil-feeding termites in Cameroon and large-bodied wood-feeding termites in Peru had higher population densities than expected by their body masses. As the population density - body mass relationship is inverse to that of the energy - body mass relationship the results suggest that the two feeding-groups also use more energy than expected by their body masses. Further, we have a relatively good understanding of the role termites play as ecosystem engineers e.g. in nutrient cycling and distribution, however, compared with our understanding of wood and litter decomposition in tropical forests quantitative data on the impact of termites in soil processes is poorly understood. In this thesis I conducted, to our knowledge, the first in situ soil macrofauna exclusion experiment using translocated soil in Peru to examine the impact of termites on soil C and N loss. I found that termites promote soil C and N loss which may be linked to the increase in microbial activity due to the passage of soil through the termite gut as well as the affect termites have on bioturbation and nutrient distribution. To conclude, in this thesis I present the first intercontinental comparison of abundance and biomass as well as the first in situ soil macrofauna exclusion experiment to date. The link between termite ecology, biogeography and evolution is discussed as well as the contribution of this thesis to the field of termite ecology.

Made available in DSpace on 2015-03-26T13:30:22Z (GMT). No. of bitstreams: 1 texto completo.pdf: 265772 bytes, checksum: 3a271bab657c2bb822d08578c132b35e (MD5) Previous issue date: 2008-09-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Termites are considered a key pest of sugarcane in Brazil and preventive control measures are usually recommended. It is not known, however, if termites really cause yield losses in sugarcane at any level of infestation and if the loss economically justfies the preventive control currently in use in the country. The objective of this work was to evaluate the effect of natural termite infestations on sugarcane productivity, as a base to establish when termite control would be economically viable. Random block experimental design was used, with productivity parameters - cane yield (tonnes of stalk per hectare), sucrose content of the juice (pol) and expected sugar yield (tonnes of pol/ha) - as response variables; termite infestation, variety and cropping season as explanatory variables, and fields as blocks. This study demonstrates a signficant relationship between natural termite infestation in sugarcane and reduction in sugar yield. Termites cause mensurable damage to ratoon sugarcane by reducing the expected sugar yield as termite infestations increase, being the reduction of 0.04558 tonnes of pol/ha per year for increases of 1% of termite infestation. They do so by reducing the cane yield but they do not affect the sucrose content of the juice. The reduction in cane yield is of 0.2755 tonnes of stalk/ha per year related to increases of 1 % in termite infestation. Our study shows that given the dilution of the control price of termites over the period of the crop and the high level of damage related to termite presence in the field, higher investments in termite control are economically suitable and could increase sugarcane productivity. Methods of termite control that are environmentally safe and economically viable must be pursued in order to reduce losses associated to increase sugarcane productivity. / Cupins são considerados uma praga chave em cana-de- açúcar no Brasil e medidas preventivas são usualmente adotadas para o seu controle. Entretanto, não se sabe se cupins causam perdas à cultura em qualquer intensidade de infestação e tampouco se sabe quando a perda justiça economicamente o seu controle. O objetivo deste trabalho foi avaliar o efeito de infestações naturais de cupins sobre a produção da cana-de-açúcar como uma base para se estabelecer em que casos o controle seria economicamente justificável. O delineamento em blocos casualisados foi utilizado para a coleta dos dados. Avaliou-se a resposta dos parâmetros de produtividade - toneladas de colmo por hectare, conteúdo de sacarose do caldo e produção esperada de açúcar - às variáveis explicativas - intensidade da infestação por cupins, variedade da cana-de-açúcar e época da colheita. Foi encontrada uma relação significativa entre a intensidade de infestações naturais de cupins em cana-de- açúcar e redução na produtividade esperada de açúcar. Os cupins causam perdas na produtividade esperada de açúcar da ordem de 0.04558 toneladas de açúcar/ha/ano para cada 1% de infestação de cupins. Esta redução é devida a uma redução na biomassa da planta de 0.2755 toneladas de colmo/ha/ano para cada aumento de 1% na infestação. Por outro lado, os cupins não causaram redução no teor de sacarose do caldo. Nosso trabalho mostra que devido à diluição do custo do controle dos cupins ao longo do período de cultivo da cana e ao alto nível de dano associado à presença dos cupins, maiores investimentos são economicamente viáveis para o controle de cupins em cana e poderiam levar a um aumento na produtividade. Métodos de controle que sejam ambientalmente seguros e economicamente viáveis devem ser buscados para aumentar a produtividade da cana-de-açúcar.

All living organisms require food for growth and survival. Heterotrophs depend on autotrophs such as green plants which can synthesize their own food unlike heterotrophic animals. Among heterotrophs, only humans and some insects have the remarkable ability to cultivate crops for food. While humans cultivate plants, three insect lineages—ants, termites, and beetles—cultivate fungi inside their nests in obligate mutualistic exo-symbioses. Interestingly, just like human agriculture, insect fungus farms are also threatened by weeds and pests, e.g. the farms of fungus-growing termites which cultivate Termitomyces fungi can be overgrown by weeds such as the parasitic fungus Pseudoxylaria. Studies on ant and beetle fungus-farming systems have uncovered the important role of chemicals and behaviour in helping these insects to protect their crops from parasitic fungi. On the other hand, studies on the termite system till now, have only revealed the presence of antifungal compounds and actinobacteria which are largely non-specific and inhibitory to the mutualistic crop fungi. Antifungal behavioural mechanisms, if present, are yet to be discovered. Therefore, this thesis focuses on different anti-Pseudoxylaria mechanisms employed by fungus-growing termites, viz. role of nest abiotic factors, mechanism of fungal recognition by termite hosts, behavioural response of termite to Pseudoxylaria presence and coupling of this behaviour to anti-Pseudoxylaria activity. The present thesis has been divided into six chapters. CHAPTER 1 gives a brief literature review on fungus-farming insects and the different mechanisms which insects employ in order to keep their fungal farms safe from growth of parasitic fungi with specific reference to fungus-growing termites. The obligate mutualistic interaction between termites and the Termitomyces fungus is 19–49 My-old and is, therefore, a very ancient agriculture system. The mutualistic fungus is cultivated on partially digested plant matter called fungus comb inside the nest and harvested by termites for nutrition. At the same time, the weedy fungal parasite Pseudoxylaria can compete with the mutualistic fungus for nutrition leading to negative effects on the fungal farms. Termite hosts are believed to use abiotic factors, antibiotics and hygienic behaviours to keep their fungal gardens free from parasitic fungi such as Pseudoxylaria. However, the actual mechanisms used by termites against parasitic fungi are unclear. Unravelling the proximate mechanisms used in fungal cultivar protection is central to understanding the evolutionary stability of these farming mutualisms. CHAPTER 2 examines the diversity and population genetic structure of Termitomyces and Pseudoxylaria strains associated with the fungus-growing termite Odontotermes obesus. Genetic diversity of cultivar and parasite could have important implications for the stability of the mutualistic interaction, e.g. genetic clonality arising from monoculture is generally thought to make populations more prone to infection by parasites. Using molecular phylogenetic tools, within-nest genetic homogeneity was found in Termitomyces species but not in Pseudoxylaria species. Lower OTU but higher genotypic diversity (within the most abundant OTU) was found in the genus Termitomyces compared to Pseudoxylaria. Additionally, population genetics methods suggested a sexual population structure for Termitomyces and clonal propagation for Pseudoxylaria species. This is the first study to investigate the population genetics of the symbiotic fungi associated with the termite genus Odontotermes or any other termite species from India. In CHAPTER 3, the effect of nest micro-environment alone on the growth of the parasitic fungus Pseudoxylaria was examined. For this, seasonal changes in nest xiii temperature and CO2 were recorded and in situ and ex situ growth experiments were performed on Pseudoxylaria. The monthly pattern of mound temperatures was found to be similar to the outside—cycling from highs in summer to lows in winter—but characterised by dampened variation compared to high daily fluctuations outside. Moreover, the mound CO2 levels were found to be orders of magnitude above atmospheric levels and, unlike the outside, were characterised by daily and monthly fluctuations. With in situ experiments during summer and winter, the effect of these dissimilar conditions—inside and outside mounds—was examined on Pseudoxylaria growth. The growth of the parasite was found to be greater inside than outside the mound. Following this, the growth of different parasite isolates under controlled ex situ conditions was examined—spanning the variation in environmental conditions that mounds exhibit daily and seasonally. High CO2 levels decreased parasitic fungal growth in general but temperature had an isolate-dependent effect. Taken together, these results suggested that the parasite is adapted to survive in the mound. However, mound environmental conditions still seemed to exert a negative effect on parasite growth, even if they cannot inhibit Pseudoxylaria completely. These results shed light on the possible new role of termite-engineered structures in impacting parasitic fungus ecology, independent of any direct role of termites in suppressing parasite growth. This is the first study to investigate the effect of abiotic factors on Pseudoxylaria growth. In CHAPTER 4, whether termites can differentiate between Termitomyces and Pseudoxylaria was investigated. In a novel, laboratory-based choice assay, termites displayed a differential response towards the two fungi by burying the Pseudoxylaria with agar. Also, termites were found to be able to differentiate between the fungi using olfactory cues, i.e. smell, alone, for this task. The mutualistic and parasitic fungi were found to emit unique volatile bouquets which could help termites to distinguish between them. This is important because, whether termites use antifungal compounds or hygienic behaviours, it is crucial that they are able to differentiate between the parasitic and mutualistic fungi so that they can selectively use antifungal mechanisms—whether chemical or behavioural—against Pseudoxylaria. This is of special significance because, many actinobacteria and anti-Pseudoxylaria compounds isolated from this system till now, lack specificity and inhibit the mutualistic Termitomyces as well. Also, fungal grooming and weeding behaviours as displayed by fungus-growing ants have not yet been reported in termites. This is the first study to show that termites have the behavioural capacity to differentiate between the mutualistic and parasitic fungi in an ecologically relevant setting. In CHAPTER 5, whether the burying of Pseudoxylaria could affect its growth was investigated. It was found that termites can utilise agar, glass beads and soil for deposition over the offered fungal plugs but the use of agar and glass beads did not inhibit Pseudoxylaria growth effectively. On the other hand, soil deposition was found to decrease growth of both Pseudoxylaria and Termitomyces fungi post-burial. However, Pseudoxylaria was found to be affected more strongly than Termitomyces. Further, hypoxia acting alone seemed to decrease only Pseudoxylaria survival without any apparent effect on Termitomyces. Therefore, hypoxia induced by soil deposition may be the reason behind the decrease in Pseudoxylaria survival. However, presence of antifungal compounds can not be ruled out and they may be selectively applied in larger quantities on Pseudoxylaria with soil deposition. This study demonstrates an anti-Pseudoxylaria activity of this insect behaviour, unique to termites among fungus-farming insects, to the presence of the parasitic fungus. CHAPTER 6 concludes the findings of this thesis and suggests a working model for the mechanism of growth suppression of Pseudoxylaria inside a termite nest. In particular, focus is on the important role of abiotic factors when combined with termite behaviour in the apparent absence of Pseudoxylaria from termite nests. These results not only shed new light on how the ecology of these fungi is affected by their termite host but also reveal the mechanistic bases that may contribute fundamentally to the evolutionary stability of this ancient mutualism.

Les termites forment un groupe animal important en milieu tropical, où leur richesse spécifique est plus élevée que dans n’importe quel autre écosystème. Ils se nourrissent de matière organique végétale à différent état de décomposition, du bois dur à la matière organique minérale du le sol. Cette diversification du régime alimentaire ne se produit que chez les Termitidae, parfois appelés « termites supérieurs », alors que les autres familles se nourrissent exclusivement de bois ou d’herbe. Les termites humivores sont extrêmement abondants en Amérique du Sud et en Afrique tropicale, mais sont relativement peu étudiés par rapport aux termites xylophages. C’est particulièrement vrai pour le groupe Anoplotermes, qui représente le groupe de termites le moins bien connu. Ce travail vise à faire la lumière sur l’écologie et la diversité de ce groupe strictement humivore, et comprend les sections suivantes :(1) Des échantillonnages standardisés dans sept sites de Guyane Française ont révèle, avec quelques exceptions, que les termites xylophages sont relativement peu spécialisés à un site. Au contraire, les espèces du groupe Anoplotermes, ainsi que les termites humivores en général, sont spécialisés à un type de forêt. Cette spécialisation contribue plus que probablement à la diversification écologique, et donc, à une augmentation de la richesse spécifique des termites humivores. (2) En utilisant les ratios d’isotopiques δ13C et δ15N, nous avons aussi trouvé qu’il existe une spécialisation des espèces le long d’un gradient d’humification chez le groupe Anoplotermes, de l’interface entre le bois pourri et le sol au sol pauvre en matière organique. Donc, au moins deux facteurs favorisent la richesse spécifique du groupe Anoplotermes dans le sol, malgré le manque d’évidence pour une séparation spatiale et temporelle entre les espèces. Cette spécialisation spécifique réduit la compétition interspécifique aux espèces se nourrissant de matière organique au même état de décomposition. (3) Ce mécanisme n’est probablement pas restreint aux espèces du groupe Anoplotermes et le ratio isotopique δ15N varie considérablement entre les termites humivores de manière générale. Les termites humivores comptent des espèces avec des régimes alimentaires différents ne partageant pas toujours les mêmes niches écologiques. Cette diversification du régime alimentaire ne c’est pas produit de manière aléatoire durant l’évolution des termites et les espèces proches tendent à se nourrir du même substrat. (4) Au niveau intraspécifique, il semble que la compétition contraigne la dynamique des colonies. En effet, chez A. banksi, nous avons trouvé que les nids matures sont surdispersés. Les nouveaux nids se trouvent principalement à une certaine distance des nids établis, plus particulièrement dans les trous laissés par les nids morts. Si ce patron est le résultat d’une sélection des sites de nidification, ou plutôt d’une exclusion compétitive reste sujet à discussion, mais met néanmoins en évidence la présence de compétition chez les termites humivores du groupe Anoplotermes. (5) Au vu de la richesse spécifique locale du groupe Anoplotermes, le nombre d’espèces décrites reste remarquablement bas. Après inspection du matériel type, seuls 30 espèces du groupe se sont avérés valides en Amérique du Sud, alors que 80% des espèces que nous avons collectées sont nouvelles pour la science. Cette disproportion entre ce qui est connu et la diversité réelle du groupe, met en évidence le besoin de réaliser des études supplémentaires pour améliorer la connaissance de ce groupe peu connu, le groupe Anoplotermes. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Os objetivos do presente trabalho foram: avaliar o processo de biodeterioração do lenho das árvores de tipuana na cidade de São Paulo e relacionar as alterações da sua estrutura anatômica e propriedades físico-mecânicas com o seu risco de queda. Nos passeios públicos de regiões selecionadas da cidade, 1109 árvores de tipuana foram caracterizadas quanto às condições de entorno, estado geral, variáveis dendrométricas, biodeterioração externa e interna e o risco de queda, estimado com modelo de cálculo estrutural desenvolvido pelo IPT. A biodeterioração e os mecanismos de resistência das árvores foram avaliados ao nível macroscópico e microscópico. As alterações nas propriedades do lenho de tipuana foram analisadas por densitometria de raios X e pelos ensaios físico-mecânicos (densidade de massa aparente; resistência à flexão) e aplicado o método de elementos finitos para análise da distribuição de tensões no lenho. As árvores de tipuana de elevada idade não apresentaram sinais de declínio, embora com estado geral considerado como crítico, pelo plantio em locais indequados, manejo inapropriado e/ou ocorrência de injúrias. O lenho foi deteriorado por fungos apodrecedores, cupins-subterrâneos e brocas-de-madeira, sendo os fungos e cupins os principais organismos xilófagos, afetando a região do cerne; a associção entre os fungos, os cupins, as variáveis dendrométricas e o risco de queda foram estatisticamente significantes ao nível de 5 %. O cupim-subterrâneo Coptotermes gestroi ocorreu em elevados níveis de infestação nas árvores, sendo considerado, no entanto, como um organismo-praga secundário, fortemente associado com lenho previamente apodrecido por Ganoderma sp.. Os fungos apodrecedores ocorrentes foram classificados como de podridão branca e mole, sendo a primeira mais comum no cerne das árvores. Como mecanismo de resistência à biodeterioração observou-se a compartimentalização do lenho, caracterizada pelo acúmulo de extrativos nas células. Os fungos xilófagos causaram reduções significativas na densidade de massa aparente, tensão de ruptura à flexão estática e módulo de elasticidade em estágios incipiente e intenso de apodrecimento do lenho. Ruptura do tronco e o risco de queda das árvores de tipuana relacionaram-se, principalmente, com a intensidade da deterioração do lenho e com a sua dendrometria. A alteração da distribuição das tensões no lenho foi analisada em relação ao estágio, tamanho e localização da deterioração no tronco das árvores de tipuana. / The objectives of the present work were to evaluate the process of biodeterioration in the wood of tipuana trees in the city of São Paulo and to relate the alterations in the anatomical structures and physical and mechanical properties with there falling risk. In the sidewalks of selected regions of the city, 1109 trees were characterized taking into consideration aspects as surroundings, general conditions, dendrometric variables, external and internal biodeterioration and falling risk estimated by using a structural model developed by IPT. The biodeterioration and the resistance mechanisms of the trees were evaluated at a macro and microscopic levels. The alterations on the wood properties were analysed by X-rays densitometry and by performing physical and mechanical tests (specific gravity; bending resistance); the tension distribution in the wood was analyze by finite-elements method. The old aged trees encountered, did not show any sign of decline, eventhough, the general aspect of their surroundings was critical by the inadequate places they were planted; inappropriate management and/or occurrence of injuries. The trees had their trunks deteriorated by xylophagous organisms, mainly fungi and subterranean-termites, and some wood borer beetle too, which affected the heartwood. The association between the presence of the first two organinsms, the dendrometric variables and the risk of falling, was statistically significant at the 5% level. The infestation of the trees by the subterranean-termite Coptotermes gestroi was at high levels, however, it was considered as a secundary plague-organism, because its attack was strongly associated with the previously decayed heartwood by Ganoderma sp.. The decaying fungi observed were classified as white rot and soft rot, being the white rot more common in the heartwood of the trees. As a resistance mechanism of the trees against biodeterioration, it was observed the compartimentalization of the wood characterized by the accumulation of extractives in the cells. Decaying fungi caused significant reductions in the following wood properties: specific gravity, rupture strength to bending and modulus of elasticity either in incipient or intense decay. Trees trunk rupture and falling risk were associated mainly to biodeterioration intensity and dendrometric variables. The alteration of tension distribution in the wood was analyzed in relation to the stage, size and position of the deterioration in the wood of the trees.

Os objetivos do presente trabalho foram: avaliar o processo de biodeterioração do lenho das árvores de tipuana na cidade de São Paulo e relacionar as alterações da sua estrutura anatômica e propriedades físico-mecânicas com o seu risco de queda. Nos passeios públicos de regiões selecionadas da cidade, 1109 árvores de tipuana foram caracterizadas quanto às condições de entorno, estado geral, variáveis dendrométricas, biodeterioração externa e interna e o risco de queda, estimado com modelo de cálculo estrutural desenvolvido pelo IPT. A biodeterioração e os mecanismos de resistência das árvores foram avaliados ao nível macroscópico e microscópico. As alterações nas propriedades do lenho de tipuana foram analisadas por densitometria de raios X e pelos ensaios físico-mecânicos (densidade de massa aparente; resistência à flexão) e aplicado o método de elementos finitos para análise da distribuição de tensões no lenho. As árvores de tipuana de elevada idade não apresentaram sinais de declínio, embora com estado geral considerado como crítico, pelo plantio em locais indequados, manejo inapropriado e/ou ocorrência de injúrias. O lenho foi deteriorado por fungos apodrecedores, cupins-subterrâneos e brocas-de-madeira, sendo os fungos e cupins os principais organismos xilófagos, afetando a região do cerne; a associção entre os fungos, os cupins, as variáveis dendrométricas e o risco de queda foram estatisticamente significantes ao nível de 5 %. O cupim-subterrâneo Coptotermes gestroi ocorreu em elevados níveis de infestação nas árvores, sendo considerado, no entanto, como um organismo-praga secundário, fortemente associado com lenho previamente apodrecido por Ganoderma sp.. Os fungos apodrecedores ocorrentes foram classificados como de podridão branca e mole, sendo a primeira mais comum no cerne das árvores. Como mecanismo de resistência à biodeterioração observou-se a compartimentalização do lenho, caracterizada pelo acúmulo de extrativos nas células. Os fungos xilófagos causaram reduções significativas na densidade de massa aparente, tensão de ruptura à flexão estática e módulo de elasticidade em estágios incipiente e intenso de apodrecimento do lenho. Ruptura do tronco e o risco de queda das árvores de tipuana relacionaram-se, principalmente, com a intensidade da deterioração do lenho e com a sua dendrometria. A alteração da distribuição das tensões no lenho foi analisada em relação ao estágio, tamanho e localização da deterioração no tronco das árvores de tipuana. / The objectives of the present work were to evaluate the process of biodeterioration in the wood of tipuana trees in the city of São Paulo and to relate the alterations in the anatomical structures and physical and mechanical properties with there falling risk. In the sidewalks of selected regions of the city, 1109 trees were characterized taking into consideration aspects as surroundings, general conditions, dendrometric variables, external and internal biodeterioration and falling risk estimated by using a structural model developed by IPT. The biodeterioration and the resistance mechanisms of the trees were evaluated at a macro and microscopic levels. The alterations on the wood properties were analysed by X-rays densitometry and by performing physical and mechanical tests (specific gravity; bending resistance); the tension distribution in the wood was analyze by finite-elements method. The old aged trees encountered, did not show any sign of decline, eventhough, the general aspect of their surroundings was critical by the inadequate places they were planted; inappropriate management and/or occurrence of injuries. The trees had their trunks deteriorated by xylophagous organisms, mainly fungi and subterranean-termites, and some wood borer beetle too, which affected the heartwood. The association between the presence of the first two organinsms, the dendrometric variables and the risk of falling, was statistically significant at the 5% level. The infestation of the trees by the subterranean-termite Coptotermes gestroi was at high levels, however, it was considered as a secundary plague-organism, because its attack was strongly associated with the previously decayed heartwood by Ganoderma sp.. The decaying fungi observed were classified as white rot and soft rot, being the white rot more common in the heartwood of the trees. As a resistance mechanism of the trees against biodeterioration, it was observed the compartimentalization of the wood characterized by the accumulation of extractives in the cells. Decaying fungi caused significant reductions in the following wood properties: specific gravity, rupture strength to bending and modulus of elasticity either in incipient or intense decay. Trees trunk rupture and falling risk were associated mainly to biodeterioration intensity and dendrometric variables. The alteration of tension distribution in the wood was analyzed in relation to the stage, size and position of the deterioration in the wood of the trees.

MSc (Food Science and Technology) / Department of Food Science and Technology / White maize-based porridge is a staple food for about 80% consumers in South Africa and sub-Saharan African countries contributing significantly to the diet of rural populations in developing countries. White maize is deficient in some amino acids and over-dependency on its porridge may lead to high prevalence of malnutrition-related health conditions. Moringa oleifera (MO) and termite (Isoptera spp.) are known to contain a substantially high amount of protein. The aim of this study was to determine the effect of powders from MO leaves and termite on the nutritional and sensory properties of instant-maize porridge. Inclusion of MO and termite powders in instant-maize porridge, at different treatments, was considered using a completely randomised design. Factor levels were: AOB-control (maize flour); BEA (maize, powders of cooked dried MO and termite); CIA (maize, powders of blanched dried MO and termite) and DJE (maize, powders of uncooked dried MO and termite). Data were analysed using SPSS version 23. The protein content of fortified instant-maize porridge (FMP) significantly (p < 0.05) increased from 10.02 to 21.20% compared to unfortified porridges. The mineral content of FMP was higher in terms of Zn, Fe, Ca and Mg. Moisture content of FMP increased from 5.00 to 6.00%. Sensory analysis showed that among fortified porridges, CIA was rated high for colour and texture, BEA higher in taste and DJE higher for aroma. AOB had higher acceptance than fortified porridges for taste. Powder from MO leaves and termite could be used in complementary foods and food supplements to increase protein and mineral contents.