Research themes

Evolutionary impacts of seasonality

We study how evolution in seasonal environments has shaped animal traits, and how disruption of seasonal cycles will impact ecology and evolution. Our goal is to identify populations, species and ecosystems at risk, to aid in establishing conservation priorities. 

Life history, physiology, and metabolism

We study how animals adjust their energetic investments among growth, activity, reproduction, and maintenance in variable environments. By studying the mechanisms by which energy is acquired, transformed, and allocated to fitness-relevant traits, we can better understand the trade-offs that shape biodiversity.

Mechanisms and consequences of stress responses

Microclimate variation combined with organismal traits to determine stress. We study stress responses as a range of timescales, and how they are altered through plasticity or evolutionary adaptations to enhance fitness. 

Some of our current projects

Winter in a changing world: the critical importance of snow

Snow determines soil microclimate and responses to climate change. When snow is covering the soil, it is protected from cold and variable temperatures. Moving up a mountain, air temperatures decrease but snow buffering increases. The combined influence of air temperature and snow cover on organismal stress exposure along an elevational gradient is unknown, and this gap in knowledge limits our ability to predict the impacts of declining snowpack due to climate warming. 

We determine how snow cover variation over the past decade in the Sierra Nevada mountains impacts cold and energy stress of willow leaf beetles, as a model for other ectotherms that overwinter in the soil in snowy habitats. We consider the whole life cycle, from growing season to growing season, to develop a theoretical and empirical understanding of how snow impacts physiology, ecology and evolution of these winter-adapted beetles.

Evolutionary physiology of a life history trade-off in Gryllus field crickets

Life history polymorphisms, where one genome produces two or more very different phenotypes, are widespread across animals and plants. Polymorphisms are maintained by life history trade-offs because there is no one “best” physiological strategy across all types of environments. We study an important life history polymorphism in insects: flight capability.

Flight is a key innovation that enabled diversification in insects. But flight is costly and reduces investment in other fitness-relevant traits, like reproduction. This has led to widespread flight polymorphisms in insects, with some individuals in a population capable of flight and others not. The evolutionary and physiological mechanisms by which flight is lost and gained are still unknown.

North American Gryllus field crickets have repeatedly evolved flight polymorphisms, 35 species ranging from fully flight capable, to mixed flight-capable and flight-incapable morphs, to fully flightless. This provides an ideal system to investigate the genetic and developmental processes underlying the losses and gains of flight capability through time.

Detecting and predicting the relative contributions of fecundity and survival to fitness in changing environments

We will use a system of montane grasshoppers distributed along an elevational gradient to understand how constraints on survival and fecundity (reproduction) will shift over time as a result of climate change. The project goal is to develop a general modeling approach that can bridge levels of biological organization, space and time to predict shifts in survival and reproduction constraints and thus improve our ability to forecast responses to environmental gradients and change.