The use of carotenoid pigments as an archive of feeding behaviour and thus as environmental markers was tested using eggs and juveniles of sea trout and brown trout (Salmo trutta L.) invertebrates from the River Don and ectoparasitic lice (Lepeophtheirus salmonis Kroyer) of Atlantic salmon (Salmo salar L.). Carotenoids were analysed by normal phase high performance liquid chromatography (HPLC) and the resulting peaks examined in multivariate analyses. Analysis of trout eggs of known parentage suggested that the pigment profile of each egg reflects the migratory history of the maternal fish and it is also representative of the entire egg batch. With the same method, eggs of unknown or disputed parentage could be identified as those of sea trout, brown trout or salmon. Diagnostic properties permitting identification were high amounts of astaxanthin in sea trout eggs; while the presence of lutein, zeaxanthin and a greater number of carotenoid peaks were indicative of brown trout eggs. In hatchery experiments it was established that the diagnostic maternal pigment fingerprint is identifiable for some 1300°d post fertilisation. In this time the majority of carotenoids are metabolised to astaxanthin esters and exogenous feeding will have begun. Muscle tissue carotenoids of juvenile trout in the River Don clearly separated 0+ trout from 1+ fish. The former arrange in a single discrete cluster on the basis of pigmentation, suggesting a common diet throughout the river catchment. Older parr show a specialist diet typical to each region but different from fry, indicating a shift in diet acquisition throughout early life stages. Pigment analysis of stream-living invertebrates and one terrestrial invertebrate revealed that all, except the terrestrial ear-wig, Rhabdiopteryx sp., Gammarus sp. and Leuctra sp., provide a homogeneous pigment profile. In contrast, Gammarus sp. was found to be the supplier of the greatest relative amount of astaxanthin, lutein and zeaxanthin. The diagnostic potential of carotenoids in sea lice was explored in samples taken from wild and farm Atlantic salmon fed on an artificial diet. Astaxanthin and canthaxanthin, which are pigments diagnostic of a natural and synthetic diet respectively, were detected. The ratio of canthaxanthin-like pigment to astaxanthin (C:A ratio) was 45:1 in farm lice and 8:1 in wild lice. Carotenoid content therefore could potentially be used as a tracer of origin of sea lice in epidemiological investigations.

Orientador: Juliana Campos Junqueira / Banca: Aguinaldo Silva Garcez Segundo / Banca: Antonio Olavo Cardoso Jorge / Resumo: A terapia fotodinâmica (TFD) tem demonstrado ação antimicrobiana sobre as leveduras do gênero Candida, sendo considerada uma técnica promissora para o tratamento de candidose. Recentemente foi relatado que a aplicação de TFD também pode resultar em ativação do sistema imunológico, contribuindo para a melhora da infecção. Assim, o objetivo desse estudo foi avaliar a ação da TFD e da terapia laser sobre a resposta imunológica à candidose experimental utilizando Galleria mellonella como modelo hospedeiro de infecção. Larvas de G. mellonella foram infectadas com diferentes cepas de Candida albicans e, após 30 min, foram tratadas com TFD mediada por azul de metileno e laser diodo emitido em 660 nm. A seguir, as larvas foram incubadas a 37°C por sete dias e analisadas diariamente para determinação da curva de sobrevivência. Para o estudo da resposta imunológica, após os tempos de 3, 6, 18 h da TFD foram realizados testes de determinação da densidade de hemócitos na hemolinfa de G. mellonella. Os dados obtidos na curva de sobrevivência foram avaliados pelo teste de Log-rank (Mantel Cox) e os resultados da análise imunológica por análise de variância ANOVA e teste de Tukey, com significância de 5%. Os resultados obtidos demonstraram que tanto para a cepa ATCC 18804 como para a cepa clínica 17 de C. albicans, a TFD prolongou a sobrevivência das larvas de G. mellonella infectadas por uma dose fúngica letal. Entretanto, houve diferença estatisticamente significante e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Photodynamic therapy (PDT) has demonstrated antimicrobial activity on the yeast of the genus Candida and is considered a promising technique for the treatment of candidiasis. Recently it was reported that the application of PDT may also result in activation of the immune system, contributing to the improvement of the infection. The objective of this study is to evaluate the action of PDT and laser therapy on the immune response to experimental candidiasis using Galleria mellonella as host of the infection. G. mellonella larvae were infected with different Candida albicans strains and, after 30 min were treated with methylene blue-mediated PDT and laser diode emitted at 660 nm. Then, the larvae were incubated at 37° C for seven days and analyzed daily in order to determine the survival curve. For the study of the immunological response, after intervals of 3, 6, 18 h of the PDT, tests were performed to determine the density of hemocytes in the hemolymph of G. mellonella. The data obtained in the survival curve were evaluated by the Log-rank test (Mantel Cox) and the results of the immunological analysis by analysis of variance ANOVA and Tukey test, with significance of 5%. The results demonstrated that for both the ATCC 18804 strain and the C. albicans clinical strain 17, PDT prolonged the survival of the infected G. mellonella larvae by a lethal fungal dose. However, there was a statistically significant difference between the PDT and the control groups only... (Complete abstract click electronic access below) / Mestre

This thesis provides an overview of case studies investigating the behaviour of freshwater crayfish, including social and reproductive interactions, decision making, and channels for recognition or processing of environmental stimuli. We described relationships between the environment and the organism and relationships among conspecifics and heterospecifics. These aspects are important, given that every decision and interaction has consequences for crayfish survival and reproduction, i.e. individual and even species success. For ethological studies in aquatic ecosystems, crustaceans, and especially crayfish, represent practical model organisms. Crayfish are advantageous over other invertebrates given their high level of social interaction in both the field and the laboratory. They exhibit unique eco- ethological behaviour in variety of feeding habits, activity cycles, habitat selection, and resource utilization at the level of species, sex, and age. Similar to vertebrates, crayfish demonstrate unique behaviours throughout their life. Subsequently, pollution impacts on native crayfish stock can result in ecosystem instability. The different reproductive strategies of females and males demonstrate that females rely on some familiarity of sexual partners as a reliable guarantee for successful mating. Crayfish females are choosier than males because of their higher energy costs for reproduction (oogenesis, incubation, parental care). While male reproduction prioritises securing their genetic information by searching for as many mates as possible. Crayfish mate preferences was analysed by facing the choosing crayfish with two equal sized mature counterparts from the same or different origin. Our conclusions could be applied in conservation research, captive breeding, and recovery programs as well as in aquaculture. The success of biological invaders has been described as the outcome from intra- and interspecific interactions. The marbled crayfish, known as parthenogenetic species with high adaptability, fast growth, early maturation, and high fecundity, established dominant status in more cases by interspecific combat victories. Fight intensity and aggressiveness decreased after dominance was established in particular pairs. Marbled crayfish seem to have an ability to conserve energy by increasing activity only at times of danger. Based on known species-specific abilities, the marbled crayfish is capable of outcompeting aggressive species, such as the red swamp crayfish. This parthenogenetic species poses a substantial threat to native ecosystems and biodiversity of aquatic environments, since it can establish not only in crayfish free habitats, but is also capable of outcompeting resident species. Recently, dilute concentrations of contaminants such as pharmaceuticals, daily-care products and pesticides have been reported to indirectly affect aquatic organisms. We found that selected pharmaceuticals can alter the behavioural patterns of crayfish, event at the very low concentration. The risks associated with surface water pollutants stresses the importance of research investigating their ecological impacts and their different/specific mechanisms of action. Prolonged exposure to the low concentrations of two pesticides exhibited changes in crayfish behavioural patterns. Various alterations in locomotion were observed after treatment in pesticide-free water. In the wild, decreased movement and activity can be a challenge for crayfish survival because of predation, even foraging to compensate for energy loss could be very difficult for less active individuals. This study suggests that crayfish behaviour assessment is a practical approach not only for investigating basic biology, or intra- and inter-specific interactions, but also for assessing the risks associated with micro-pollutants.

South Australian mangroves consist of only one single species Avicennia marina (Fosk.) Vierh.var australasica (Walp) Moldenke, 1960. They are distributed discontinuously within St. Vincent Gulf and Spencer Gulf and provide significant valuable habitat both in economical and ecological terms. The Fisheries Act 1971-1982 protected the existence of mangroves and the Harbour Act 1936-1981 controlled removal of mangrove areas in coastal development. To date very few ecological studies have been conducted in the South Australian mangroves, particularly on the infaunal organisms that have an important role in maintaining the ecological dynamic within the estuaries systems. As this is the first study on infaunal mangrove communities in the inverse estuaries of South Australia, there was no prior data for ecological comparison. The study was conducted at three mangroves location (Garden Island, Middle Beach and Saint Kilda) close to Adelaide in May 2000 and 2001. Overall the study has reported that the infaunal mangrove assemblages of South Australian mangroves were comparable to other temperate mangroves. The infaunal communities were characterised by lower diversity and abundance compared to the tropical or subtropical mangroves. The infaunal zonation related to the tidal gradient and habitat variation was detected. Most infauna organisms occupied the surface layers and substantially decreased towards the deeper layers. The study also suggested that sediment structure of mangrove systems were complex and infaunal communities responded differently to the change of environmental conditions both in small scale and larger scale. Thus, assessing the infaunal communities structure in mangrove systems should be based on ecological characteristics rather than geographical positions. The examination of dominant polychaetes families showed that different species have different responses to the environmental cues within mangrove systems. The study did not find that any polychaete species was restricted to mangroves only as they all were also found in the habitat adjacent mangrove forest. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2003.

Predation is one of the important selective factors that regulate the species composition of benthic invertebrate communities. The study objective was to investigate the invertebrate distribution in two contrasting habitats in Lake Takern, southern Sweden, submerged Chara vegetation and emergent Phragmites australis vegetation, and to investigate the influence of predation from fish on certain invertebrates. Laboratory studies were used to estimate handling time and the intake rate (mg/sec) by the fish based on the optimal foraging model. In the field, fish and invertebrates were collected with gill nets and hand nets respectively and the fish gut content was analyzed. In total, sixteen invertebrates’ taxa were collected from the two habitats. The proportion of the invertebrate’s overlaps from each of the habitat was calculated by Renkonen index and with Sorensen diversity index. Both indices showed a similarity larger than 65%, indicating that there was no significant difference in the invertebrates’ distribution in the P. australis and the Chara habitat. The fish caught with the gill nets were: roach (Rutilus rutilus), perch (Perca fluviatilis), tench (Tinca tinca), and rudd (Scardinius erythrophthalmus). The caught perch had eaten: Asellus aquaticus, Gammarus lacustris, Corixidae, and the larvae of Chironomidae and Zygoptera.A comparison was made on the invertebrates found in the field and the ones observed from the gut of the perch, and the findings were that the invertebrates that had more occurrence in the gut were less in proportion in the benthic samples. In the laboratory experiment perch ( Perca fluviatilis) was used as the predator fish and the prey organisms were Asellus aquaticus,Gammarus pulex, and Corixidae of three size categories. The results showed that perch handling time for A.aquaticus of the different size categories, was not significantly different (p>0.05); and the same results were valid for Corixidae and G. pulex. However, the intake rate of perch across the prey and their size categories were significantly different. The handling time was not significantly different which means that the predator fish will gain more in terms of intake rate as it prey on larger size prey items, thus harmonizing with the optimum foraging theory. / MSc Ecology and Environmental Science

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 137-150). Also available on the Internet.

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 195-219).

Dissertation (Ph.D.)--Auburn University, / Abstract. Includes bibliographic references.

Because of the eutrophication resulting from increasing anthropogenic activities, hypoxia (i.e. dissolved oxygen < 2.8 mg O2 L-1) is on the rise globally. The objective of this research was to understand more about the effects of hypoxia on the marine benthic communities. Particularly, it focused on the latent effects and indirect effects of hypoxia by investigating how early exposure to hypoxia affect the later life stage of a marine gastropod Crepidula onyx, and how hypoxia alter the bacterial composition of biofilms and the subsequent larval settlement of marine invertebrates. In the first study, the larvae of C. onyx were exposed to 2, 3, and 6 mg O2 l-1. Under low food concentration (Isochrysis galbana at 1 × 105 cells l-1), larvae in both hypoxic treatments (2 and 3 mg O2 l-1) required a longer time to become competent to metamorphose. But when they did, they had a similar size and total lipid content to the control larvae. Moreover, the latent effects of early hypoxic exposure on the juvenile growth were evident. After 2 weeks development in field, the growth rate, mean dry weight and filtration rate of juveniles were significantly reduced in the hypoxic treatments. However, there was no discernible effect on larvae or juveniles when the food concentration during the larval stage was doubled (I. galbana at 2 × 105 cells l-1), suggesting that the latent effects of hypoxia can be offset by larval access to high algal concentration. In the second study, the biofilms were exposed to hypoxia and normoxia in microcosms for up to 7 days, and their bacterial community composition was analysed by terminal-restriction fragment length polymorphism (T-RFLP). The results suggested that hypoxia altered the bacterial community structure within biofilms, and the difference between the hypoxia and normoxia treatments increased through the length of exposure period. The resulting changes in biofilms did not alter the larval settlement response of a model species (i.e. C. onyx) in laboratory assays. Nevertheless, when the biofilms were deployed in the field to allow natural larval settlement and recruitment, biofilms that had been exposed to hypoxia altered the overall larval settlement pattern of different marine invertebrates, potentially leading to a shift in the benthic invertebrate community. This research suggested that periodic hypoxic events and the resulting exposure of organisms to hypoxia during their early development might have effects that persist across the life history. Moreover, it highlighted the possibility that the effects of hypoxia on species composition and structure of benthic invertebrate communities might be mediated through changes in biofilms and subsequently larval settlement and recruitment. To conclude, this research demonstrated that hypoxia could affect the growth in the later life stages of marine invertebrates and the recruitment of the benthic communities. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

The carrot fly (Psila rosae F.) is an important pest of the cultivated carrot (Daucus carota) and other crop species in the family Apiaceae, since the larvae burrow into and feed on the developing roots. Current P. rosae control relies heavily upon the use of chemical insecticides, but these are inadequate. The aims of this study were to investigate the chemical ecology of P. rosae, particularly with regard to long range attractant and repellent semiochemicals suitable for incorporation into integrated pest management strategies; the incorporation of attractant host plant extracts, or semiochemical attractants, into the monitoring programme; and the development of an autodissemination trap for release of the pathogenic fungus Entomophthora schizophorae in the field for biological control. A number of techniques for the extraction of volatile semiochemicals from a wide range of host and non-host plant species, and P. rosae adults themselves, were employed and compared. Samples were analysed by gas chromatography (GC), and the biologically active components in these complex natural product extracts were located by coupled GC-electrophysiological techniques and identified by coupled GC-mass spectrometry (GC-MS). Responses to the electrophysiologically active compounds were compared using electroantennographic (EAG) analysis: one unusually high EAG response was observed to a toxic component in hemlock (Conium maculatum) leaf extract (y-coniceine). Of the forty-two EAG active components identified from common crop species and C. maculatum, eight had not previously been reported. A range of bioassay techniques (including four-arm star olfactometers, V-tube olfactometers, and oviposition bioassays) were employed to determine behavioural activity of the samples and identified compounds, but only the oviposition bioassay showed significant behavioural discrimination to y-coniceine. Further studies of longer range behavioural responses to volatile semiochemicals were performed in the field. Significant responses were seen to a known field attractant (combined trans-asarone and hexanal) and, for the first time, to a microwave assisted solvent extract of celery (Apium graveolens) leaf. A prototype autodissemination trap for E. schizophorae was produced and evaluated.