Grant: Discovery Grants Program - Individual

This research investigates the mechanisms that underly fundamental physiological processes freshwater (FW) aquatic insect larvae possess to regulate their internal ion and water levels. In this respect the longterm goal of my research is to significantly advance mechanistic knowledge of water and ion regulation in FW aquatic insect larvae. These mechanisms are studied in the context of the environmental contaminant salt and other de-icing agents, utilizing larvae of midges, mayflies and mosquitoes. The larval stages of the mayfly Hexagenia rigida and the midges Chironomus riparius and Chironomus dilutus live in sediment at the bottom of shallow FW lakes (e.g. Lake Erie), ponds, streams and marshes where they are important food sources for other animals, clean the environment by feeding on decaying waste matter and serve as important indicators of ecosystem health. A recent study tracked salt levels of over 300 FW lakes in North America and noted sustained increases in salt levels in these lakes, predicting that within the next 50 years levels would reach 10 times what is deemed as suitable for drinking and sustaining the ecosystem. This poses a threat to aquatic life and H. rigida, C. riparius and C. dilutus larvae are excellent model organisms to study these effects. This research involves exposing the insect larvae to FW contaminated with salt and de-icers and assessing water and ion transport mechanisms and how these may be modified in the face of salt and de-icing agents. This will provide us with a deeper understanding of how these species may adapt to changing salinity. We also aim to study how salinity affects the osmoregulatory physiology of the disease spreading mosquito, Aedes aegypti. This mosquito spreads arboviral diseases like dengue, chikungunya and zika in tropical and subtropical regions of the world. The larvae of these mosquitoes typically inhabit FW; however, more recently have been found in habitats contaminated with seawater. These habitats are implicated in the prevalence of disease during dry seasons when traditional FW habitats that are more inland are scarce. This research involves raising A. aegypti larvae in seawater contaminated water and examining how mechanisms that regulate salt and water balance may be modified. Overall, this research addresses important real-life societal problems such as the effects of freshwater salinization on FW insects that are key to ecosystem health. Furthermore, the research provides essential information about the underlying physiology that allow the disease vector A. aegypti to exploit new habitats which ultimately perpetuate the prevalence of disease. This research has the potential to inform mosquito control programs and will inform policy makers contributing to the protection of inland sources of FW by providing them with data to understand the ecosystem dynamics of these critical FW reserves.