Mosquitoes are a significant global public health threat, claiming hundreds of thousands of lives annually due to the various pathogens they transmit, which result in diseases including dengue, malaria, and Zika. While various strategies and practices are in place to manage mosquito populations, these methods may be challenged due to a rise in insecticide resistance in some mosquito species, the increasing impacts of global climate change, and invasive species populations. This work presents four distinct projects investigating Culex spp., Ae. albopictus, and Ae. j. japonicus mosquitoes using a range of methods and techniques to bring novel insight into the biology and ecology of these mosquitoes. The first project focuses on the thermal preference and response to thermal cues of three Culex species which vary in host preference and climate of origin. The second project explores the effects of different rearing temperatures and regions of origin on the thermal performance, life-history traits, and nutrient reserves of Ae. albopictus mosquitoes. The third project shifts to the optimization of a species-specific attractive toxic sugar bait (ATSB) trap targeted toward invasive Ae. j. japonicus mosquitoes. The fourth chapter, which is field oriented, focuses on determining the role of elevation on mosquito biodiversity and pathogen prevalence. Collectively, these works explore how mosquitoes interact with their environment to support research-informed decisions in future mosquito control practices. / Master of Science in Life Sciences / Mosquitoes are the deadliest animals in the world, causing over half a million deaths every year. Mosquitoes are disease vectors, meaning they are able to transmit pathogens (such as viruses or bacteria) that cause diseases including malaria and Zika, which can lead to severe illness and death because of the lack of treatment and vaccines, or even access to these in some instances. While there are current strategies in place to reduce mosquito population numbers in areas with high levels of pathogen transmission, we are seeing increasing difficulties in managing and predicting these mosquito populations. Certain mosquito species have become resistant to chemical treatments and the growing impacts of climate change (such as more extreme weather and temperatures) are two factors that are expected to greatly influence mosquito biology and global distribution in the near future, which may expose new human populations to mosquito-borne illnesses. These issues have inspired the following projects to gain more information on how mosquitoes interact with their environment and their hosts, to highlight traits or behaviors that could inform novel mosquito management strategies in the future.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24799号 / 医博第4991号 / 新制||医||1066(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 石見 拓, 教授 川口 義弥 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Invasive alien species are a growing threat globally that causes negative effects on the environment, economy and human health. Part of the solution is to involve the public to help reduce the spread. The aim of this study was to examine the public knowledge and to analyze people's reactions when they receive information about invasive species. Further I analyze the information dissemination method used by the county board of Västerbotten and examine whether there was any difference between the property owner’s responses depending on what type of invasive species they had on their property. A survey was designed to acquire information from property owners in Västerbotten county who had an information letter by the Swedish authorities in 2021 about invasive species on their property. The survey was sent to 123 property owners and the response rate was 49%. The survey didn’t show any significant difference between the property owner’s responses depending on what kind of invasive species they had. Results showed that the majority of the respondents considered the information letter helpful and a large percentage had taken action to combat the invasive species after receiving the letter. The results showed that the property owner's knowledge increased after receiving the information letter. In conclusion, the study shows that information letters are an effective method for property owners to take action and increase their knowledge of invasive species.

Invasive plants can alter pollination dynamics by disrupting pollinator visitation and pollen transfer dynamics. However, a consensus regarding the direction of their overall effects (competitive vs. facilitative) remains elusive. Here, we evaluate the role of floral traits and spatial scale (community vs. floral neighborhood) in mediating invasive Cirsium arvense effects on resident plant species at multiple stages of the pollination process. C. arvense decreased pollinator visitation rate at the community level only for species with radial floral symmetry. At the floral neighborhood scale, pollinator visitation rate to all resident species was lower in the presence of C. arvense regardless of symmetry. C. arvense altered patterns of conspecific pollen receipt at the floral neighborhood scale, but the direction of the effect varied by plant species. We argue that these scale-dependent effects may be mediated by differences in foraging range and behavior of the main pollinators in the community. C. arvense, however, did not affect the overall reproductive success of resident species at either scale, suggesting that plants at our study sites may not be pollen limited. We further show evidence suggesting that C. arvense may alter the structure of community-level plant–plant interactions via heterospecific pollen transfer by subverting the roles of resident pollen donors within the pollen transfer network. Overall, our results suggest that generalized species (with radial flowers) may be more susceptible to invasive species’ effects than specialized ones (bilateral flowers) and highlight the need to consider scale-dependent effects in order to develop a more predictive understanding of invasive species effects in nature.

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Background: There are few studies on the uptake of non-invasive prenatal screening, but those available suggest substantial variation in uptake in the initial years in which it was offered. There is a need to update the earlier evidence and determine whether there has been any change in usage trends as the number of users have increased. This will help inform policy makers about NIPT uptake under currently existing policies and guidelines which can help inform whether to maintain or refine policies on NIPT. Objectives: The primary objective of this thesis was to investigate recent trends in NIPT utilization, and the secondary objective was to identify differences between pregnant individuals aged 40 years and above and/or with a history of previous aneuploidy who opted for first-tier (first-line screening) or second-tier (contingent screening) NIPT and pregnant individuals aged less than 40 years with no history of previous aneuploidy. Methods: This retrospective cohort study used a province wide birth registry from Ontario and the population studied comprised pregnant individuals with an expected date of delivery from August 1st, 2016 to March 31st, 2020. Results: Of 536,748 pregnant individuals resident in Ontario during the study period, 27,733 were classified as high-risk of giving birth to a baby with a chromosomal aneuploidy and 509,015 were classified as low-risk of giving birth to a baby with a chromosomal aneuploidy. Uptake of NIPT has increased every year since 2016. We found substantial variation in NIPT between regions within the province. Highest uptake was found in urban areas, highest neighbourhood of income and education quintiles, high-risk population, among those with a prenatal care visit in the first trimester, multiple pregnancy, multigravidity, body mass index within the normal range (18.5-24.9 kg/m2), and OHIP funding. Conclusion: Our results suggest a need to provide more education/training about NIPT and funding eligibility to health professionals and pregnant individuals, including low-risk pregnant individuals in the first-tier (first-line screening) NIPT funding policy, to ensure equitable assess.

Buffel grass (Cenchrus ciliaris ) has been established in Uluṟu‐Kata Tjuta National Park since 1968. To date, the influence of buffel grass on the Park's flora and fauna has been largely unassessed. The objectives of this study were to determine if buffel grass dominates vegetation communities at the base of Uluṟu and if buffel grass habitats are associated with lower reptile and amphibian species richness than endemic vegetation communities. We used vegetation transects to measure the amount of buffel grass and genera of endemic vegetation at 26 sampling locations around the base of Uluṟu. The vegetation survey data were paired with pitfall trap data from reptile and amphibian captures at the same sampling locations. Indicator species analysis and non‐metric multidimensional scaling were used to analyse the vegetation and herpetofaunal community data. Our analyses determined five distinct vegetation communities around Uluṟu. At the base of Uluṟu, buffel grass dominated half of sampled areas and the rest of the inselberg's base was dominated by Themeda grasses. Buffel grass habitats had significantly higher herpetofaunal species richness than the Themeda habitats that dominated other areas at Uluṟu's base. Herpetofauna species richness in buffel grass‐dominated habitats was also significantly higher than all vegetation communities except for Triodia‐dominated habitats. These observations do not directly indicate that buffel grass presence promotes higher species richness of reptiles and amphibians since the observed patterns may be driven by factors such as proximity to breeding sites and abiotic variables not directly related to the grass itself.