WHAT WE DO!
We are interested in how the life history of organisms interacts with, and scales up to impact population dynamics. Our research combines theory, lab experiments, and field experiments across a range of organisms. Alongside collaborators, some of our works spreads into disease biology (malaria & mosquitoes), some focuses on predatory-prey interactions (zooplankton & phytoplankton), and some on how environmental conditions govern population dynamics through their impact on life history (tortricid moths & temperature). The connecting theme, however, is that the life history of these organisms has a strong impact on their population biology.
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Explore each of our project areas below.
Tick Dynamics and Lyme Disease
The newest Public Health concern is being caused by an unlikely enemy: Climate Change. Lyme disease, a neuromuscular infection is caused by transmission of the Borellia bacteria from the Blacklegged Tick, Ixodes scapularis. With warming weather, the blacklegged tick has found its way into Canada, and now Lyme disease is the greatest vector-borne disease in Canada with a 500% increase in cases in the past decade.
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Our research attempts to understand ticks and Lyme disease by approaching this problem from two opposite directions. On the one hand we are attempting to examine what effects host-community dynamics play on the prevalence of infections in tick populations. From the other side, we examine ticks from a public health and clinical perspective and take novel approaches to connect simulations of tick populations to real world cases.
A bite from this little guy can lead to loss of motor function and other neurological abilities
Black lines represent simulations of Lyme disease risk and coloured lines show the actual cases of Lyme Disease in the Kingston area.
Simulations we have generated of tick populations and how that relates to risk in the Kingston area.
A bite from this little guy can lead to loss of motor function and other neurological abilities
Tea Pests in Japan
They are small, but they are many! The tea tortrix Adoxophyes honmai is one of the most damaging pests to Japanese tea plantations. The larvae damage the tea by both consuming the leaves for food, and using silk to roll leaves into protective homes. The problem for tea plantations—and the scientific interest for ecologists—is that the populations undergoes multiple outbreak cycles each year.
Our recent work found that the outbreaks are large amplitude cycles (‘limit cycles’ in math-speak) caused by the increased life-history rates that occur during warmer parts of the season. But why should evolution favour a life history that gives rise to outbreak cycles? Along with collaborators in the US and Japan, we are using a combination of experiments, time-series analysis and mathematical modelling to study the ultimate cause of these outbreak cycles.
The model organism for our pest research
Experimental apparatus for temperature control experiments (a: water chiller, b: insulated aquaria with heaters) and images of a tea tortrix egg mass (c), adult (d), and larva (e).
The model organism for our pest research
Oxygen and Daphnia
Oxygen is fundamental for the vast majority of life on earth. However, despite this some organisms live in extremely depleted environments. To cope with hypoxia, several strategies exist ranging for anatomical to physiological traits.
To deal with the changing oxygen levels in lakes, daphnia have different traits for the up-regulations of hemoglobin and visually display this trait in a red phenotype. Our research is interested in determining the mechanism of this trait specially whether it is based on evolution or phenotypic plasticity. We combine field and lab experiments to further examine this trait and help gain a better understanding of how organisms are able to cope with hypoxic environments.
Different daphnia display various strategies to deal with hypoxic conditions of lakes
Different daphnia display various strategies to deal with hypoxic conditions of lakes
Daphnia’s Food Resources in Round Lake
To understand the “behavior of a population” you need to take a close look at the life history of an organism, such as Daphnia pulicaria, as it adjusts to seasonal changes in its natural environment. The top herbivore, D. pulicaria, impacts the lake ecosystem as a consumer of phytoplankton along with other zooplankonic grazers. As primary production decreases below the incipient limiting concentration of 0.4 mg C/L (ILC; Larsson & Lampert, 2012) in summer, it also coincides with the time at which daphnia adopt a diel vertical migration pattern (DVM) to avoid planktivorous fish.
Of interest is the coincidence of this yearly pattern of declining availability of primary production in summer, DVM, and the increase in red phenotypes in daphnia. The up-regulation of hemoglobin enables a higher affinity to oxygen presumably to facilitate more efficient feeding on the seston around the oxycline. This research aims to emphasize the importance of seston by comparing egg production in spring when phytoplankton is key, to the fecundity of ‘red’ females in fall and winter. Through carbon analysis of seston it can be demonstrated that as Daphnia come into deeper water through their DVM they would be exposed to higher concentrations of this potential food source. This would ultimately help to produce a population that can make it through the winter where they can exploit the temperature, nutrient and light dependent increase in phytoplankton, as early as March.
Like what you see?
Interested in a graduate position? Collaboration? Undergraduate Project? Then check out the People page based on the research team and have them answer your questions!