Insect Thermal Biology and Energetics


Identifying how genetic variation is transformed via physiology into organismal phenotypes and fitness is a central question in biology. Intermediary metabolism is a crucial step linking changes in metabolic enzymes, via flux through pathways of energy metabolism, to whole-organism performance. Intermediary metabolism and energetics are the lens through which I study the effects of temperature on whole organisms.

"At the heart of science is an essential balance between two seemingly contradictory attitudes - an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from nonsense".

Carl Sagan, "The Demon-Haunted World - Science as a Candle in the Dark", 1997, p304

Announcement: I will be starting up my lab in Integrative Biology at UC Berkeley in July 2014, so I will be recruiting next summer. Watch this space!

Welcome to my homepage!

Temperature is one of the most important abiotic factors influencing the physiology, ecology, and evolution of ectothermic organisms, and anthropogenic climate change is driving the most rapid changes in thermal conditions in human history. I aim to understand how insects respond to changes in their overwintering thermal environment, on physiological, ecological, and evolutionary scales. My research addresses two main questions:

How do insects respond to thermal change during winter?

Winter imposes two interacting stresses - cold and resource limitation. Current climate change projections predict higher average temperatures, which will mitigate cold stress but increase energetic stress by raising rates of metabolism in dormant ectotherms, and also increases in extreme events, which mean that organisms will have to tolerate an increased incidence of both high and low extreme temperatures throughout the year. A lack of insight into the physiological response of insects to winter climate change is a major impediment to successfully predicting insect population dynamics in a changing world. I am investigating the genetic, physiological, and life-history mechanisms by which insects respond to thermal change over winter using a comparative approach among species (Pelini et al. 2009 PNAS, Williams et al. 2012 Climate Research), between populations of a species (Williams et al. 2012 PLoS ONE), and within species (go here to read about my current work on the physiological and biochemical architecture of cold tolerance in Drosophila melanogaster).


What is the potential for evolution of these responses?

Differentiation in metabolic responses to winter climate change occurs over micro-evolutionary (intra-population) to the macro-evolutionary (inter-population and inter-specific) scales, and the presence of heritable variation is a prerequisite for adaptation to climate change. Understanding the genetic architecture of variation in winter-relevant metabolic phenotypes such as propensity to diapause, metabolic rate and thermal sensitivity thereof, and nutrient storage and mobilization, and the contribution of these traits to fitness, will therefore advance our ability to predict population-level responses to winter climate change and explain global gradients in metabolic physiology. A major focus of my research is identifying heritable metabolic phenotypes that accompany thermal adaptation to winter conditions both intra- and inter-specifically (e.g. Williams et al. 2012_PLoS ONE).

Background image courtesy of Stock Xchng