UC Research Repository

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The UC Research Repository collects, stores and makes available original research from postgraduate students, researchers and academics based at the University of Canterbury.



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ItemOpen Access
Quantifying the reproductive ecology and immune-related gill gene regulation in Stigmatopora macropterygia.
(2023) O'Neill, Ruby Yve
The extent of parental investment can significantly influence reproductive success of a species. It necessitates the allocation of precious resources to incubate developing embryos, often prompting adaptations for larger body sizes, and meticulous regulation of immune responses to prevent the rejection of these embryos. Syngnathids are the only known vertebrates to have evolved male pregnancy, making them an invaluable resource for comparative research on the reproductive investments and potential trade-offs exhibited, independent of the female reproductive tract. In this thesis, I explore the reproductive ecology, gill gene expression, and immune sexual dimorphisms in Stigmatopora macropterygia, a pipefish species endemic to New Zealand. Reproductive ecology methods were used to assess the selection gradient for male reproductive success based on body length and width, examine possible sexual size dimorphism, and analyse population sex ratios using field catch data. The results indicate notable variations in female body width in comparison to males, with no significant distinctions in body length between the sexes. Moreover, neither body length nor width appeared to significantly impact male reproductive success. Sampling data highlighted a greater prevalence of females in the population. Genetic analysis, incorporating a differential gene expression analysis, highlights substantial similarity in gene expression patterns between male and female gill tissues. The minimal differential expression between sexes was also reflected in the immune-related genes of the gills. This research provides insight into the complex interplay between morphological evolution and gene regulation in this New Zealand endemic species. It underscores the need to include alternative ecological factors, such as breeding timing, mate preferences, and female size, in shaping male reproductive success. While gene expression remains largely consistent in gill tissues, the identification of exclusive differentially expressed genes in males hints at unique genetic strategies. My thesis not only contributes to our understanding of the evolutionary patterns and reproductive ecology of S. macropterygia but also pave the way for future investigations into the broader evolutionary patterns within syngnathids.
ItemOpen Access
A PCR-based assay for screening substrates for Aspergillus fumigatus for application in kiwi hatcheries
(2023) Rowe, Stephen P.; Stott, Matthew; Brett B; Dhami MK
Captive facilities across New Zealand strive to mimic natural conditions for captive animals as closely as possible. In the case of the kiwi (Apteryx spp.), captive habitats are augmented with natural stimuli such as soils, leaf litter, bark, plants, logs, and mosses. Interaction with these introduced stimuli has been shown to encourage normal foraging behaviour and is speculated to aid in inoculating young animals with healthy microbial communities. However, introducing non-sterile natural stimuli into the captive environment also carries the risk of exposing kiwi to diseases such as aspergillosis, coccidiosis, and candidiasis. Aspergillosis is of particular concern to rearing facilities – the disease is most commonly attributed to exposure to Aspergillus fumigatus, an opportunistic fungal pathogen. Here we present a PCR-based screen to qualitatively detect the presence and/or absence of A. fumigatus in soils. Soil samples collected from nesting sites of rowi (Ōkārito brown kiwi, Apteryx rowi) in the Ōkārito region of the West Coast were screened for A. fumigatus using a species-specific primer set coupled with a basic DNA extraction. Willowbank Wildlife Reserve soil and substrate samples were also screened as a baseline comparison representing captive rearing facilities. Results from the assays showed that the extraction technique was effective at isolating A. fumigatus DNA at detectable levels from a variety of soils, and that Ōkārito soils did not harbour a higher abundance of A. fumigatus than those found at Willowbank. This preliminary screening method could be used by facilities in New Zealand to quickly and cheaply screen soils and substrates for A. fumigatus before introducing them to captive enclosures.
ItemOpen Access
Learning and Teaching: Innovative Learning Environments
(2023) Fletcher, Jo; Everatt J; Subramaniam Y; Ma T
ItemOpen Access
Issues and Challenges with Assessment in Stand Alone Moodle
(2014) Farley, Helen; Murphy A; Bedford T; Orth G