Understanding the temperature dependence of consumer-resource interactions

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Changes in environmental temperature can strongly impact consumer-resource interactions such as those between predators and their prey. These interactions form the basic building blocks of biodiversity and drive the flux of nutrients and materials through ecosystems. A three-pronged approach that combines computation and informatics, mechanistic theory, and laboratory experiments will be used to advance scientific understanding of these processes. For the informatics prong, a comprehensive database has been compiled (203 traits and 403 species measured over a total range of 66° C) and will be analyzed to investigate effects of temperature on functional traits such as body velocity and encounter rate. Based on the results, the second prong is to develop a mechanistic model that uses physiological and ecological principles to incorporate temperature effects on population growth rate, mortality rate, and consumption rate. This model will yield predictions for how temperature affects population abundances, species coexistence, and species invasions for diverse taxa in a variety of habitats. The third prong will be to test the full suite of predictions for temperature responses using a system in which all traits can be measured simultaneously. This system is tri-trophic - bladderpod plant, harlequin bug, and two parasitoids - and its life history traits and population dynamics are extensively measured and well understood. Testing predictions within this system will enable model refinement and the inclusion of behavioral aspects, such as search efficiencies of the two parasitoid species in locating host eggs. This work will be used to quantify to what extent entire systems can be described by each of their constituent consumer-resource pairs. Thus, the findings will inform how the effects of temperature on single consumer-resource pairs can be scaled up to study food webs. Together, this research will help to illuminate how fluctuations in temperature can affect parasitoid enemies, a crucial issue in biological pest control. Moreover, this research program will help to elucidate mechanisms for how temperature impacts biodiversity, corresponding to the potential loss of goods, food, and drugs that are critical to humans. Given the evidence for global warming, understanding the effects of temperature on ecosystem dynamics is a particularly pressing problem.