The earth’s climate is rapidly changing and predicting the biological response to these changes is a major scientific challenge. To date, most research has been focused only on understanding how warmer temperatures impact organisms. Yet, less is known about the combined impacts of rising temperatures and changes in precipitation. Insects are particularly vulnerable to the combined stress of higher temperatures and drier conditions, but little is known about the vulnerability of insect species adapted to different climates. Yet, insect species provide many important ecosystem services, like pollination, and there is growing evidence that insect populations are declining around the world. This research project will compare the physiological tolerance of related insect species from contrasting climates (northern Norway, central Norway, central France, and southern Spain) to better understand future responses. Specifically, the project will measure the temperature sensitivity of metabolism and water loss of insects to better understand how vulnerability to warming and desiccation differs geographically and among species. Because these physiological responses can change as a function of the microorganisms living inside and on the surface of insects, DNA metabarcoding will be used identify insect species and the microorganisms they support. These results will be combined with future climate projections to develop a new class of physiologically informed models to predict which species are at greatest risk or likely to benefit under future climates. The ultimate goal of this project is to transfer the knowledge gained to researchers and policy makers interested in how insects will impact ecosystems, agriculture, and food security in the future.
Terrestrial insects are in decline and there is increasing evidence we are facing an insect biodiversity crisis that threatens agriculture by altering ecosystem services such as pollination. At the same time, other insect species are thriving and expanding their distributions and becoming pest species. Climate change has been implicated to explain these patterns, but the causal mechanisms remain largely unknown. We propose that past research has not considered a fundamental physiological challenge insects face. Because warmer temperatures increase metabolic rate and water loss rates, their small sizes make insects particularly vulnerable to both desiccation and higher energy demands. Yet, no study to date has attempted to quantify these physiological responses to determine vulnerability to changes in temperature and precipitation. We propose an ambitious interdisciplinary collaboration to fill this gap in knowledge and advance the field by:
1) quantifying the thermal sensitivity of metabolism and water loss in insect communities from different climates (Finnmark, Trøndelag, central France, and southern Spain). We will sample across different taxonomic and functional (pollinators, herbivores, predators, decomposers) groups and quantify the temperature and humidity of the microclimates they occupy.
2) using DNA metabarcoding to identify patterns of relatedness between populations and species to facilitate comparative analyses. We will also describe the symbiome of coevolving organisms that use insects as hosts and are known to alter host physiology.
3) developing a new class of eco-physiological models and evolutionary theory that incorporate the dual challenge posed by temperature and water loss to predict vulnerability, performance, species distribution, and adaptive evolution.
We argue this research will have transformative impacts across fields of study and on our ability to better understand and predict insect responses to environmental change.