Animals which complete seasonal migrations are exposed to more than a single environment and parasite community. Due to the additional parasites, migrants may be expected to allocate relatively more resources to immune defense. Conversely, the high energetic cost of migration may constrain resources such that the immune response is compromised during migratory flight, suggesting diseased animals are less likely to migrate long distances. However, little is known about how birds cope with infectious disease while under the demands of migration despite being blamed, in part, for the long-distance transport of disease. My proposed research will investigate how migratory birds balance the demands of migration with the need to defend themselves against parasites by examining the plasticity of migratory traits in response to infection.
The majority of insect species that emigrate from deteriorating habitats do so as sexually immature individuals. A prolonged pre-oviposition period where resources are directed to flight machinery and fuel for migration could have a negative effect on subsequent reproductive output. Using the true armyworm, my study aims to address how flight and food quality affect the reproductive output of migrants and non-migrants with specific emphasis on natural rearing conditions.
The Pacific salmon have long been an ecological, economic and cultural foundation of communities in the Pacific Northwest of North America. Their viability is now threatened, however, as populations have been falling to historic lows over the past two decades. This loss prompted a judicial inquiry by the government of Canada in 2009 on the causes of decline, which found that changing marine conditions are likely responsible. Specifically, rising temperatures, reduced food availability, increased abundance of non-resident predatory fish and increased rates of sea lice infections interact to limit salmon during their coastal migration. In my proposed research, I will evaluate how the interaction of these stressors affects the aerobic capacity of migratory salmon using experimental and field-based approaches.
November 21, 2014
Migration is an evolutionary adaptation employed by some insect species in the face of seasonally deteriorating habitat conditions. It is believed that there exists a physiological trade-off between reproduction and migration, and that the two states are incompatible. Seasonal migrants often rely on environmental factors such as photoperiod, and temperature as indicators of deteriorating habitat. Differences in the onset of sexual development have been observed not only between migratory and non-migratory moth species but also between migratory (North American) and non-migratory (Azorean) populations of the same species (Pseudaletia unipuncta) reared under the same ecological conditions. My research compares and contrasts the behavioural, developmental, and morphological characteristics of the Hawaiian, Azorean (both non-migratory), and North American (migratory) armyworm under varying temperature and photoperiod conditions.
November 14, 2014
Males and females often have differing reproductive strategies to increase their individual fitness. The benefits of sexual selection can be acquired through mechanisms which can act on many levels: behavioural through female mate choice, or postmating through sperm competition and cryptic female choice. The objectives of my research are to determine the traits that females select for in attractive males in Drosophila melanogaster and tease apart how attractive and unattractive males perform in both pre- and postmating sexual selection. These different aspects of sexual selection at both pre- and postmating levels were examined to determine how they contribute to overall male mating success, providing insight into how populations evolve in response to sexual selection.
Predator–prey interactions shape ecology, and reacting to a predator threat is crucial for survival. As many prey individuals survive predator attacks, it is important to recognize the lasting effects of perceived predation risk, from populations to individual neurobiology. We have a good understanding of the mammalian brain network that processes predator ‘fear’, but in birds this network remains largely unknown. I used auditory predator playbacks to simulate predator encounters in wild black-capped chickadees (Poecile atricapillus). Using immediate-early gene immunohistochemistry, I examined the short– and long–term effects of perceived predation risk in brain areas thought to be involved in the avian ‘fear’ network. My results demonstrate that perceived predation risk affects the brains of wild birds, and that these effects may persist following predator encounters
November 07, 2014
Predators affect prey populations beyond directly killing individuals. A growing body of research shows that the “fear” of being preyed upon (i.e. perceived risk of predation) can induce costly anti-predator behaviours that are powerful enough to reduce prey reproduction and survival. The majority of this research has dealt with the effects of fear on prey only during the nesting period, leaving the possibility that the total effect on populations is underestimated. My research examined how threat of predation effected the behaviour of Song Sparrows (Melospiza melodia) after the nesting period. To accomplish this we manipulated the threat of predation with predator playbacks. My results show that parents respond to predation threat. We are still assessing how if predation threat affects offspring behaviour as well.
October 31, 2014
October 24, 2014
October 17, 2014
October 03, 2014
September 26, 2014