Life-history trade-offs, seasonal time constraints, and the optimization of body size

点击翻译按钮获取中文摘要

My research program aims to understand how life histories are influenced by the environment, and to apply this understanding to the conservation of exploited populations and species at risk. Life-history traits have a direct and context-specific effect on fitness, and understanding the trade-offs and ecological context under which life-histories have evolved is central to understanding local adaptation, demographic rates, and extinction risk. Body size is central to many models of life-history evolution, yet there is no consensus on how body size is optimized. In order to understand life-history evolution more broadly and apply this knowledge effectively to conservation and management, we need to understand how size is optimized across ontogeny. My short term goal is to develop a better understanding of how size is optimized, and to explore how optimization is influenced by the physical environment. My first objective (PhD1, Msc1) is to examine how maternal body size and the length of time available for embryo/juvenile development jointly affect optimal investment in offspring, and hence optimal juvenile size. This objective aims to provide a much-needed and broadly-applicable framework in which to understand how parents optimize the size of their offspring, thereby laying a theoretical groundwork in which to explore variation in life-history expression that depends on initial size, as well as the effects of size-selective harvesting in exploited populations. My second objective (PhD2) is to test the idea that parent-offspring conflict plays a central role in body size evolution, and to develop life-historical hypotheses for Bergmann's Rule and its congeners. This objective aims to clarify the trade-offs and environmental influences that govern body-size evolution, such that we are in a better position to predict how size in general will respond to environmental change. Finally, I will use long-term data to investigate how trade-offs between growth and reproduction are altered by decadal warming patterns, using long-lived reptiles as model organisms (PhD3, MSc2). This objective will help elucidate how the thermal environment affects key life-history trade-offs, and how long-term changes in temperature are likely to affect survival and recruitment in populations adapted to cooler northern environments. In sum, this work will train five HQP, and it will help resolve the mechanisms and processes that affect the evolution of body size. In the short term, it will provide researchers with a general framework in which to consider the optimization of size across ontogeny. In the long term, it will help clarify how life-histories more broadly will respond to changes in the environment, as it lays the foundation for subsequent investigation into how specific types of environmental variation/anthropogenic disturbance affect life-history expression/evolution that is mediated through size.