Orientador: Carlos Frederico Wilcken / Banca: Edson Luiz Lopes Baldin / Banca: Nádia Cristina de Oliveira / Banca: Luiz Alexandre Nogueira de Sá / Banca: Leonardo Rodrigues Barbosa / Resumo: O gênero Eucalyptus (Myrtaceae) é originário da Austrália e hospeda várias espécies de insetos da família Psyllidae. Dentre elas, o psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), que é considerada uma das principais pragas introduzidas desta cultura no Brasil e em outros países. O parasitóide Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) é indicado como principal agente no controle biológico desta praga. Devido a sua importância econômica, esse trabalho objetivou estudar as populações de G. brimblecombei e de P. bliteus em floresta de Eucalyptus camaldulensis para determinação de sua distribuição espacial, flutuação populacional, a relação com fatores meteorológicos (temperatura e precipitação), e determinar o índice de parasitismo pós liberação de P. bliteus em campo. O estudo da dinâmica populacional do psilídeo-de-concha e do seu parasitóide foi realizado através da utilização de 53 armadilhas amarelas e da coleta de 53 ramos/avaliação em um talhão de 19 ha com E. camaldulensis em Luiz Antônio, SP, com 42 avaliações, entre janeiro de 2006 a janeiro de 2008. Concluiu-se que as populações de ambas espécies apresentaram distribuição espacial agregada, possuem correlação inversamente proporcional à temperatura, e a precipitação pluviométrica; ocorreu aumento no índice de parasitismo em todos os pontos de liberação de P. bliteus. no período avaliado / Abstract: The genus Eucalyptus is originally from Australia and hosts several species of insects of the family Psylidae. Among them, the red gum lerp psyllid is considered one of the main pests of this crop introduced in Brazil and other countries. However, for the control of phytophagous hemiptera, the treatment with insecticides proved to be expensive and unsustainable. The psylllid specific parasitic wasp Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is indicated as the main biological control agent of this pest. Due to its economic importance, this study aimed to evaluate G. brimblecombei and P. bliteus population in Eucalyptus camaldulensis plantations to determine their spatial distribution, population fluctuation with weather interactions (temperature and rainfall), and also to determine parasitism rates in the field after release of P. bliteus. The study of population dynamic of red gum lerp psyllid and its parasitoid (53 traps sampled and 53 branches sampled per sampling dates) was carried out on E. camaldulensis plantations in 19 ha area in Luiz Antônio municipality (SP, Brazil), from January 2006 to January 2008 (42 sampling dates). This research indicated that population of both species noticed especial aggregated distribution, inversely proportional subject to temperature. Besides, was found correlation between both species and rainfall. There was also at measured period an increase in the parasitism rate at all release points of P. bliteus / Doutor

Made available in DSpace on 2016-04-28T20:15:29Z (GMT). No. of bitstreams: 1 2008- Daniela de Oliveira Franco Acuna.pdf: 2634530 bytes, checksum: 5433beffd9a4776e67f732e78762b6bb (MD5) Previous issue date: 2008-02-19 / The snail, Achatina fulica (Giant African snail), is registered in almost all Brazilian territory, and may act as an intermediate host of parasites of the man. This study aimed to describe the morphology of the nematode larvae found in A. fulica, through light (LM) and scanning electron microscopy (SEM), and to relate the prevalence of infection to the collection places of the snails and to the antropic activity. Sixty snails were collected from April/2006 to April/2007, in the Mesquita City, RJ, transferred to laboratory, kept in terraria, measured and dissected to verify the infection, distribution of the cysts in tissues of the snails. The cysts were collected and the larvae were separated. The material thus obtained was used to LM and SEM. The occurrence of A. fulica in the less conserved area was greater than that in the more conserved area. However, there was not a significant relation between the intensity of infection and the collection places and the antropic activity. Fourteen snails (23%) were infected and the biggest number of cysts/snail verified was 130 and the minor was 1, in snails that with 106 and 55mm of shell length, respectively. A strong correlation was observed between the size of the snail and the number of cysts and there was a greater concentration of these in the pallial cavity, 87%. Of this total, 49% were in the area more vascularized and 38% in the less vascularized area of this cavity. The cysts presented spherical shape, light pink colored and measured 0.97-1.57mm in diameter and with an unique larva involved by an amorphous material. Two hundred twenty two encysted larvae were recovered, 30 larvae were used to the morphological studies. The length of the larvae varied of 2.57-5.8mm, being classified in: small - until 3.5mm; medium - of 3.53-4.5mm and great - above of 4.52mm. The average length of the larvae in the three groups was of 2.85; 3.87 and 5.23mm, respectively, and the total average of 4.2mm. The larvae presented white cuticle, shining, transversally striated and the lateral line extending to the posterior extremity of the body. In the anterior end, it is observed mouth provided with three lips, with amphids and papillae, followed by a muscular oesophagus with average length of 0.61mm, ending in an esophagus bulb. The nervous ring it was observed in the medium third of the oesophagus and the intestine ends in an opening located next to the posterior end. The tail had a length varying of 0.15-0.42mm, is located after this opening may present two types of endings: abrupt or that it sharpens gradually. The difference in the ending of the tail may suggest sexual dimorphism, although not to have been observed reproductive structures. The identification to the specific level was not possible, this pointed to the necessity of continuation of this study. The expressive population density of A.fulica observed in the conserved area less it confirms the influence of the antropic action on the dispersion of this snail. / O molusco Achatina fulica (Caramujo gigante africano) ? registrado em quase todo territ?rio nacional, havendo a possibilidade de atuar como hospedeiro de parasitos do homem. Este estudo objetivou descrever a morfologia dos est?gios larvais de nemat?ides encontrados em A. fulica, atrav?s de microscopia de luz e eletr?nica de varredura, e relacionar a preval?ncia de infec??o aos locais de coleta dos moluscos e ? atividade antr?pica. Sessenta moluscos foram coletados de abril de 2006 a abril de 2007, no munic?pio de Mesquita, RJ, transferidos para o laborat?rio, mantidos em terr?rios, medidos e dissecados para verifica??o da infec??o, distribui??o dos cistos pelos tecidos do molusco, coleta dos cistos e obten??o das larvas. Procedeu-se a fixa??o e o processamento para microscopia de luz e eletr?nica de varredura. A ocorr?ncia de A. fulica na ?rea menos conservada foi maior que na ?rea mais conservada. Por?m n?o houve uma rela??o significativa entre a intensidade de infec??o aos locais de coleta e ? atividade antr?pica. Quatorze moluscos (23%) estavam infectados e o maior n?mero de cistos verificado por molusco foi de 130 e o menor de 01, em moluscos que apresentavam 106 e 55mm de comprimento de concha, respectivamente. Foi observada uma forte correla??o entre o tamanho do molusco e o n?mero de cistos encontrados e maior concentra??o destes na cavidade paleal, 87%. Desse total, 49% estavam na ?rea mais vascularizada e 38% na menos vascularizada da cavidade. Os cistos apresentavam formato esf?rico, colora??o rosada e mediam de 0,97 a 1,57mm de di?metro e na maioria das vezes com uma ?nica larva que se encontrava envolvida por um material amorfo. Foram recuperadas 222 larvas encistadas. Destas, 30 foram utilizadas no estudo morfol?gico. O comprimento das larvas variou de 2,57 a 5,8mm, sendo classificados em: pequeno at? 3,5mm; m?dio de 3,53 a 4,5mm e grande - acima de 4,52mm. O comprimento m?dio das larvas nos tr?s grupos foi de 2,85; 3,87 e 5,23mm, respectivamente, e a m?dia total de 4,2mm. As larvas apresentavam cut?cula branca, brilhante e estriada no sentido transversal e linha lateral at? a extremidade posterior do corpo. Na extremidade anterior, observa-se a boca provida de tr?s l?bios, com anf?dios e papilas, seguida por um es?fago musculoso com comprimento m?dio de 0,61mm, terminando em um bulbo esofagiano. O anel nervoso foi observado no ter?o m?dio do es?fago e o intestino termina em uma abertura localizada pr?ximo ? extremidade posterior. A cauda, com comprimento variando de 0,15 a 0,42mm, se forma a partir desta abertura e apresenta dois tipos de termina??es: abrupta ou que afina gradativamente. A diferen?a na termina??o da cauda pode sugerir dimorfismo sexual, apesar de n?o terem sido observados prim?rdios de ?rg?os reprodutores. Com os resultados obtidos n?o foi poss?vel a identifica??o ao n?vel espec?fico, havendo dessa forma a necessidade de continua??o deste estudo. A densidade populacional expressiva de A. fulica observada na ?rea menos conservada confirma a influ?ncia da a??o antr?pica sobre a dispers?o deste molusco.

The Enemy Release Hypothesis proposes that introduced species often achieve larger individual sizes and greater population abundance in their introduced range because they have escaped their natural enemies - predators and parasites - that regulate populations in their native range. The main objective of this study is to test the Enemy Release Hypothesis (ERH) by investigating the identity, prevalence and intensity of parasites in two marine species introduced to New Zealand - the recently introduced but spatially restricted Asian portunid crab, Charybdis japonica, and the longer-established Asian nesting mussel, Musculista senhousia. Host choice of a native generalist parasite presented with the non-native and native mussels, and prey selection by a native predator presented with these bivalves will be examined. This is the first study of its kind in New Zealand. The parasite fauna of the only established New Zealand population of C. japonica (Waitemata Harbour, Auckland), was compared to that from (a) a population of C. japonica from its native region (Japan) and (b) to multiple populations of the native New Zealand crab Ovalipes catharus, a native New Zealand portunid. Results showed the introduced crab harboured only one species of endoparasite (a nematode), and two types of melanised lesions. Neither the parasite nor the lesions were present in the native crab populations. The native crab was host to only one parasite species, which occurred at very low prevalence, and was present in only one of the six populations examined from throughout New Zealand. Carapace width in the introduced crab was no larger than that reported in literature from its native are, but was larger than carapace widths of the Japanese sample. M. senhousia was examined from five sites within New Zealand. Parasites in M. senhousia were compared with a sympatric native bivalve, Austrovenus stutchburyi, two native mytilids, (Perna canaliculus and Xenostrobus pulex) and with samples of M. senhousia from Italy and the USA where it is introduced, and Japan where it is native. Two native generalist parasites, the pea crab Pinnotheres novaezelandiae, and a copepod, were found within M. senhousia in New Zealand, but only at low prevalence. A greater array of organisms was associated with the native bivalves. No parasites were recovered from any of the overseas samples of M. senhousia, including the Japanese samples. This may be caused by the preservation medium used, but could be a true reflection of the parasite fauna in these populations. The site where the two native parasites were exploiting M. senhousia was the only site sampled where two native mussels, P. canaliculus and X. pulex, also occurred. Consequently, effects of these two generalist parasites on the three mussel species were examined. In P. canaliculus, presence of native pea crabs was associated with lower tissue dry weight and greater shell depth. Shell width and depth were both greater in the presence of copepods. However, the prevalence of pea crabs and copepods was much lower in M. senhousia compared to the two native mussels, indicating some release from the effects of these parasites for the non-native species. Experimental choice tests showed that the pea crab, P. novaezelandiae, does not actively select M. senhousia as a host, preferring the larger native mussel, P. canaliculus. Rates of infection of M. senhousia are, therefore, likely to remain low in natural habitats where there are large numbers of native hosts. In addition, a generalist predator, the crab O. catharus, showed no preference when foraging on the three mussel species under experimental conditions. Thus, some predation pressure may be exerted on M. senhousia by this native crab in the natural environment. Investigation of multiple populations of both native and non-native species has shown large variation in parasite prevalence and intensity among populations of each species. After examining C. japonica and the comparable native O. catharus, evidence to support the ERH was found to be weak. As the native crab was relatively free of parasites, it seems unlikely that parasite infection is important within native populations and therefore, the success of C. japonica is unlikely to be caused by comparatively greater freedom from parasites (a central tenet of the ERH). There was also no evidence for host-switching by native parasites into the introduced C. japonica population. In contrast, native parasites were present at very low prevalence in the non-native mussel M. senhousia. Length of time since introduction can be an important factor in host switching between native and introduced hosts, but unless prevalence of these parasites is high, the introduced species still escapes from enemies that could control a population. Therefore every non-native species needs to be examined using multiple populations to investigate variation in parasite fauna, prevalence and intensity, as the same species, if introduced numerous times, could potentially show contrasting results for the ERH unless multiple populations are examined.

Introduction Schistosomiasis is one of the most important and widespread diseases of rural poverty. Worldwide, approximately 779 million people are at risk of infection, with 207 million already infected. Infections with Ascaris lumbricoides, hookworms and Trichuris trichiura, collectively known as the soil-transmitted helminths (STHs), are also highly endemic throughout the tropics, particularly in resource-poor settings. An estimated 1 billion people worldwide are estimated to be infected with STHs. Schistosomes and STHs often co-exist in the same epidemiological settings and, given the high prevalence of concurrent multiple species infections (multiparasitism), a combined approach to prevention and control could lead to significant improvements, including reducing costs associated with single-species control programmes. In China, rigorous national schistosomiasis control efforts over the past 60 years have decreased the prevalence by over 90%; however, since 2000 the number of infected individuals has been rising, possibly indicative of a re-emergence. Fishermen, migrant communities and poor households in rural areas may be most at risk of single and multiple-species parasitic infections and the associated morbidity. Objectives This Ph.D. thesis is structured according to four main goals and a number of specific objectives: Firstly, to update estimates of S. japonicum prevalence, intensity and associated morbidity levels in Hunan province, China, according to the third national PES carried out in 2004; Secondly, to investigate existing barriers in access to preventive, diagnostic and treatment services for advanced schistosomiasis; Thirdly, to compare and evaluate direct and proxy methods of measuring household socio-economic position, according to data on income, savings and asset-based estimations of wealth; and Finally, to explore and identify behavioural, demographic, economic, environmental and social risk factors associated with the distribution of S. japonicum, STHs and multiple species infections, in two villages of the Dongting Lake region, Hunan province, China. Methods Firstly, we used data from the third national schistosomiasis periodic epidemiological survey (PES) of 2004. In Hunan province, the PES was carried out in 47 villages of the endemic Dongting lake area. A total of 47144 human serological, 7205 stool, and 3893 clinical examinations were performed. For the reservoir hosts, stools from 874 buffaloes and other domestic animals were examined for schistosomiasis by the miracidial hatching test. Secondly, we conducted an in-depth study involving interviews with 66 schistosomiasis control staff and 79 advanced schistosomiasis patient, and six focus group discussions (FGDs), in the Dongting lake region, between August 2002 and February 2003. Using the Health-Access Livelihood framework we examined availability, accessibility, affordability, adequacy and acceptability of schistosomiasis control in the Dongting lake area. Lastly, we carried out two village-wide parasitological, clinical and questionnaire-based investigations between October and December 2006. Parasitological examinations for the prevalence of S. japonicum and the STHs were performed by the Kato-Katz thick smear method, with repeated sampling of each individual. We took fingerprick blood samples to assess haemoglobin levels, using a B-haemoglobin HemoCue photometer. The household-based questionnaire focused on direct and proxy measurements of household wealth, while the individual-based questionnaire focused on demographic and behavioural factors, treatment history and self-perceived symptoms. Results Human sero-prevalence was 11.9% (range: 1.3-34.9% at village level), and the rate of egg-positive stools was 1.9% (0-10.9%) for the same population. The prevalence of infection among buffaloes was 9.5% (0-66.7%). Extrapolating to the entire population of the Dongting Lake region, an estimated 73225 people and 13973 buffaloes were infected. Most frequently reported symptoms were abdominal pain (6.2%) and bloody stools (2.7%). Accessibility and affordability were major barriers in access to schistosomiasis control. Many of staff interviewed indicated that a majority of patients who develop advanced schistosomiasis resided in mildly-endemic or non-endemic settings. None of the patients interviewed had any form of health insurance, and most of their health expenses were out-of-pocket payments. Exploratory factor analysis generated internally robust proxy wealth indices, however these were not complementary to direct measures of household wealth, as indicated by low correlation co-efficients. We found wide disparities in household ownership of durable assets, utility and sanitation, within both settings. Pooled data from the rural and peri-urban settings highlighted structural differences in socioeconomic position (SEP), more likely a result of localised urbanization and modernization. We found higher infection prevalences in rural settings, than in peri-urban settings, for schistosomiasis (6.3% and 6.7% respectively), ascariasis (8.3% and 2.2%, respectively) and trichuriasis (5.1% and 0.5%, respectively), but lower for hookworms (0.1% and 1.5% respectively). Multiple species infections (2.6% and 0.2%, respectively) were less prevalent than single species infections (14.5% and 10.4%). There were significant disparities in the prevalence of parasitic infections between poorest and least poor quintiles of the cohort population. Anaemia and other symptoms, especially headache, stomach ache and swollen stomach, were common in both rural and peri-urban village settings. Conclusion The studies conducted within the framework of this Ph.D. thesis document the current situation pertaining to schistosomiasis and the STHs in Hunan province, China. Our findings highlight the need for increased surveillance, monitoring and health education, with relation to schistosomiasis and STHs, in non-endemic or post-transmission control settings. Based upon these results, we call for improved diagnostic tools, particularly in the case of low intensity infections and for hookworm, and propose an extension of the use of available infrastructure, human resources, knowledge and technology by integrating prevention and control of schistosomiasis with that of other intestinal helminths, particularly STHs. In the future, our studies may form a base from which to further examine local needs and priorities for parasitic disease control in the area.

The aim of this thesis project was to elucidate patterns and processes associated with the biotic interactions in a natural plant–herbivore–parasitoid food web characterized by spatial and temporal heterogeneity with regard to species composition. The system examined is based on island populations of the perennial herb Meadowsweet (Filipendula ulmaria, Rosaceae), located in the Skeppsvik Archipelago. The area is subject to isostatic rebound, amounting to 0.85 cm per year; this makes it possible to calculate the age of the rising islands. Meadowsweet colonizes new islands when they are about 100 years old. Meadowsweet is consumed by two major herbivores in the study area: Galerucella tenella and Altica engstroemi (Coleoptera: Chrysomelidae). Both herbivores overwinter in the topsoil and successful colonization occurs when the islands reach a height that prevents the beetles from being removed or killed as a result of wave wash during the winter. I found that both herbivores significantly reduced individual plant fitness and population growth rate. A “cafeteria experiment” with Galerucella showed that this beetle discriminated between plants from different islands, avoiding plants from old islands which contained high concentrations of putative defence compounds, while readily accepting plants from younger islands which contained lower concentrations of these chemicals. Further, the plant species exhibited a trade-off between growth and production of the putative defence compounds. Taken together, these results were interpreted as providing evidence of herbivore-driven evolution of resistance in Meadowsweet. Further, laboratory studies suggested that Galerucella gradually includes a less preferred host plant (Rubus arcticus, Rosaceae) in its diet as Meadowsweet resistance increases. This implies that Galerucella drives its own host-breadth enlargement by selectively inducing a ‘rent rise’ in the original host, Meadowsweet. In a number of field studies I showed that the oligophagous parasitoid Asecodes mento (Hymenoptera: Eulophidae) has a strong positive effect on Meadowsweet seed set by removing large numbers of G. tenella larvae. This top-down effect is, however, altered by the presence of a close relative of G. tenella, namely G. calmariensis, which is monophagous on Purple loosestrife (Lythrum salicaria, Lythraceae). G. tenella experiences associational susceptibility when coexisting with G. calmariensis since the latter supports a higher and more fit pool of shared parasitoids and because Meadowsweet attracts a higher proportion of the shared parasitoid females than Purple loosestrife. This implies that G. tenella densities are very low in coexisting populations and that Meadowsweet experiences associational resistance and produces more seeds when co-occurring with Purple loosestrife. Thus, selection for increased resistance in Meadowsweet is likely to be relaxed in populations mixed with Purple loosestrife. I conclude that the evolution of plant resistance is likely to depend on the length of time and intensity of selection. When Meadowsweet colonizes new islands it experiences a period of enemy-free space; followed by a midlife and ageing with selection by herbivores. The intensity of this selection does, however, depend on the presence of additional plant and herbivore species.

Brown-headed cowbird (Molothrus ater) parasitism on the endangered black-capped vireo (Vireo atricapilla) is a management concern. Management for black-capped vireos in east-central Texas has focused on habitat restoration through vegetation modification. Loss of productivity due to parasitism, however, may limit the potential habitat restoration in restoring black-capped vireo populations. I investigated the relationships between frequency of parasitism on black-capped and white-eyed (V. griseus) vireos and characteristics of the neighboring avian assemblage to identify avian characteristics useful for predicting expected frequency of parasitism. I located and monitored vireo nests in March–July 2006 to determine frequency of cowbird parasitism on the 2 vireo species on 6 study sites on private land in east-central Texas. I conducted 100-m-radius circular-plot point count surveys on study sites from 1 April– 31 June 2006 to identify neighboring avian assemblages. All black-capped vireo nests (n = 20) and 81% of white-eyed vireo nests (n = 27) were parasitized. Species richness, species evenness, cumulative bird abundance, and cowbird host abundance did not differ significantly among study sites. Parasitism frequency was positively correlated with the number of cowbirds detected (r2 = 0.673, P= 0.045). Parasitism frequency was negatively correlated with abundance (r2 = 0.687, P = 0.042) and proportion of (r2 = 0.692, P = 0.040) of black-and-white warblers (Mniotilta varia), known cowbird hosts. I did not find a relationship between parasitism frequency and abundance of other cowbird hosts. The relationship between black-andwhite warbler abundance and parasitism frequency may reflect an interaction between parasitism and the vegetation characteristics associated with black-and-white warblers, suggesting the need for future study of the relationships between parasitism frequency and vegetation characteristics in the study region. The frequency of parasitism I observed suggests that cowbird control may be an important management tool if management objectives in the study region continue to include recovery of black-capped vireo populations. Number of cowbirds may be a reasonable predictor of expected parasitism frequency in an area, which may be useful to land managers in selecting areas for implementation of cowbird control.

Obligate brood parasites lay their eggs in nests of other species, relying on these host parents to care for their offspring. This phenomenon has been a curiosity amongst researchers since its first description and has become a model study system for testing such ideas as coevolution and species recognition. This thesis examines a few of the many questions that arise from this breeding system. The New Zealand Grey Warbler (Gerygone igata) and its brood parasite, the Shining Cuckoo (Chrysococcyx lucidus) are used as the main study species, although research on the eviction behaviour of Common Cuckoos (Cuculus canorus) has also been conducted. First, the current state of knowledge and recent discoveries regarding nestling rejection abilities of hosts is reviewed in chapter one. Second, a comparative study of New Zealand passerine begging calls has been conducted to test for begging call similarity between a brood parasite and its host, as well as developing a new technique for detecting the mode of coevolution that may be occurring in the parasite – host relationship. Parent-offspring communication in Grey Warblers is also examined to test for both parental and nestlings Parents use both alarm calls to warn offspring of potential danger, and also parental feeding calls to elicit a begging response from nestlings. By contrast, nestlings are able to signal both age and short term levels of need to parents through the acoustic structure of the begging call. The evolutionary costs and benefits of egg eviction behaviour in the Common Cuckoo are also tested. An experimental approach showed that egg eviction had a growth cost, but this cost was temporary and restricted to during and immediately after the egg eviction phase. A pattern of compensatory growth was observed after the eviction period, so that during the later nestling stages there was no difference in mass, and no difference in fledging age. Finally, variation in the Grey Warbler breeding biology and Shining Cuckoo parasitism rates are examined through both time and across latitudes. This research has shown a counterintuitive pattern of breeding phenology across latitudes. These patterns have implications for Shining Cuckoos both in terms of timing of available nests and host selection. Keywords: Begging call, breeding phenology, brood parasitism, coevolution, Common Cuckoo, eviction, Grey Warbler, parent-offspring communication, Shining Cuckoo.

Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.

Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.

Studies were conducted to determine basic aspects of intake and digestion of native pastures by young sheep in the Falkland Islands, and to evaluate practical methods to improve the productivity of these animals. The studies were conducted in support of Industry and Government initiatives to reinvigorate Falklands’ agriculture. The current industry is based on broad diameter wools harvested from sheep grazing poor quality native pastures, and sheep suffer low growth rates, poor productivity and high mortality, and farmers rely on small flocks to produce a single commodity for their total income. The dramatic collapse of wool markets in the 1980’s crippled the Falklands’ wool industry and farmers have relied heavily on subsidies for more than 12 years. The studies in this thesis were initiated to support the efforts to reinvigorate Falklands’ agriculture, and they examined basic aspects of the nutrition provided to sheep by native pastures and evaluated practical methods to improve the survival of sheep, their subsequent rate of growth and productive value to the economy. Five studies examined specific hypotheses posed at the outset of the research programme and they were broadly supported by the data presented in the thesis: · A wether trial was used to benchmark the productivity of wool sheep in the Islands, and the trial demonstrated that substantial genetic variation exists within the national flock that may be exploited in the future to improve the productivity of the wool industry, · Microhistological techniques were used in conjunction with n-alkane marker technology to investigate the diets consumed by sheep grazing native pastures. The diet studies concluded that the low quality of native pasture in the Falklands during autumn, winter and spring restricts growth and productivity of young sheep, · Studies with weaner sheep treated with controlled release anthelmintics established that infection with gastrointestinal nematodes exacerbates poor nutrition of young sheep consuming native pastures, · A short-term metabolism study demonstrated that native pasture hay fortified with molasses and urea, or winter forage crops may be used as supplements to enhance sheep productivity, and · Forage crops were grown and evaluated under Falklands’ conditions, and when lambs were fed the resulting highly productive and nutritious forages, the study demonstrated that lamb growth can be increased significantly, and lamb carcasses offer local farmers the potential to diversify farm income by using existing Falklands’-bred lambs to develop an export meat industry The data presented in this thesis demonstrate that the potential to improve the productive and financial position of Falklands’ farmers is substantial. If both the local Industry and Government maintain their joint commitment to industry-restructure, pastoral development and enterprise diversification, the Falklands’ agricultural economy stands to benefit considerably by adopting low risk solutions to address widespread problems.