Ph.D. Research
After graduating from Smith College, I moved to The Rockefeller University where I pursued a Ph.D. at the intersection of animal behaviour, genetics, and evolution, studying the insidious but fascinating Aedes aegypti mosquito.
Aedes aegypti mosquitoes impose a severe burden on human health worldwide, as they transmit dengue, Zika, chikungunya, and yellow fever viruses, as well as parasites that cause debilitating conditions like elephantiasis. The natural history of Aedes aegypti is incredible; currently found on most continents, this species has invaded diverse ecosystems, thriving in the face of climate fluctuations, and natural disasters like intense droughts. How are Aedes aegypti mosquitoes able to remain resilient and adapt to dynamic environments? How do they make flexible behavioural and reproductive decisions suitable to their external environment? Our work focused on these questions and builds upon decades of observations from both the laboratory as well as from the wild.
With an aquatic life cycle as larvae and pupae, and a terrestrial life cycle as adults, Aedes aegypti mosquitoes have evolved adaptations that enable survival in these distinct habitats. Both adult males and females are pollinators, and they feed on nectar for energy. To reproduce, however, females — and only females — need blood protein from human hosts, and they are notoriously adept hunters. Once a female locates her host victim, she lands on their skin, punctures through it, and feasts on their blood to double her body weight. Over the next 3-4 days, she pauses her hunting drive and redirects the blood nutrients into developing her clutch of ~100 eggs. She then searches for freshwater, at the edge of which she can lay her eggs and wherein the hatched larvae can grow while their mother resumes her quest for another blood meal.
Under optimal environmental conditions, freshwater for egg-laying is abundant in natural and manmade containers found around human settlements. But, in the face of unpredictable rain spells and increasingly intense droughts, a female carrying eggs must consider tradeoffs: should her eggs be laid with subsequent hatching uncertain, or should her eggs be retained inside the ovaries with considerable metabolic resources likely utilized? Our work explored these tradeoffs and characterized the behavioural repertoire of a reproducing female experiencing different conditions of freshwater availability. We used modern genetic tools and sequencing technologies to understand how female Aedes aegypti mosquitoes are innately capable of making appropriate reproductive and behavioural decisions. Specifically, we investigated how this species has evolved molecules that can protect mature eggs within the ovaries for extended periods of retention, such as during droughts that would be unsuitable for the survival of any laid offspring.
Our work suggests that the molecular players sustaining egg retention are at the heart of Aedes aegypti’s reproductive strategy, their reproductive resilience, and their ability to invade ecosystems with otherwise inhospitable climate conditions.
Read my research as a pre-print on bioRxiv here:
Read my full doctoral dissertation here.
