Collaborative Research: RUI: Life history strategies within a population depend on cellular and organismal traits that underlie differences in resource acquisition and allocation

All organisms need energy to fuel the biological processes of life. In general, this energy can be allocated to three broad categories: growth, self-maintenance, and reproduction. Said in another way, organisms can allocate acquired energy to grow their body to achieve a larger size, to repair and maintain their body to live longer, or to reproduce and create the new bodies of their offspring.

However energy is limiting, so if more is invested into growth, less can be invested into self-maintenance and reproduction. This results in allocation trade-offs, where some individuals are better at growing, while others may be able to attain extreme longevity. While these patterns generally hold in animals, in many species scientist’s observe certain individuals who appear to be able to do it all with few consequences, but little is known about how this occurs.

This proposal studies a long-lived seabird, Leach's storm-petrels, that has been studied continuously at our site for the past 70-years. This has revealed that while we have many individuals who show the expected allocation trade-offs there are also many that somehow have escaped that trade-off. Our work explores the molecular and cellular processes that underlie the ability to avoid this trade-off.

This work is focused on a fundamental question in biology, and will help us to understand how molecular processes and organismal performance affect longevity. This work also strongly supports undergraduate science education, and will result in the development of inquiry-based scientific modules used in middle school and high school classrooms.

Factors driving the evolution of diverse life history strategies both within and between species remain a fundamental question in ecology and evolutionary biology. Because resources are finite, many life history traits are subject to intrinsic trade-offs. However, theoretical models have proposed that variation in individual acquisition of resources can produce apparent positive correlations between investment in reproduction and investment in survival instead of the expected trade-off.

This proposal tests these models by examining phenotypic variation in strategies to balance the trade-off between current reproduction and survival in a long-lived seabird, Leach's storm-petrels (Hydrobates leucorhous), that has been studied continuously at our site since 1953. This proposal has three primary objectives: 1) to better understand the molecular, cellular, and organismal performance traits that underlie the observed variation in trade-off strategies in this population, and 2) to determine if individuals who appear to escape the trade-off do so via higher foraging efficiency as proposed in theoretical models, and 3) to determine whether these trade-off strategies are fixed or plastic in response to environmental variability.

The proposed research is informed by our 70-year demographic data set, and utilizes (i) a combination of novel technology and molecular tools to understand the molecular, cellular, and organismal performance traits that underlie the observed variation in trade-off strategies, and (ii) experimental manipulations to explore whether these strategies are fixed or plastic.

This project is jointly funded by the Integrative Ecological Physiology Program and the Established Program to Stimulate Competitive Research (EPSCoR).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.