Warming increases predator hunger for prey, and predators that sit and wait for their prey may be at an advantage during climate change.

This video is from the Michigan State University Spatial & Community Ecology Lab (SpaCE Lab: www.communityecologylab.com) as part of an experiment investigating the responses of predator-prey relationships to increasing temperatures from anthropogenic climate change. The video was taken by Tyler Treakle, MSU Kellogg Biological Station REU student, and Laura Twardochleb, MSU PhD '20. The video demonstrates a predator (juvenile damselfly, Enallagma) sitting and waiting to consume its prey (zooplankton, Daphnia) at a given water temperature. As temperature increases with anthropogenic climate change, warming increases metabolic demand for food in ectotherms like these invertebrates. In a warming world, predators that actively pursue their prey (like sharks, or the macroinvertebrate backswimmer that was also used in this experiment) may be more likely to starve than predators like this damselfly larvae or snakes that sit and wait for prey, because active predators have to consume more food to maintain their activity levels. These changes could cause larger effects across entire food webs as certain predators are able to withstand warming more than others. 

This video accompanies the following paper, by Laura Twardochleb (MSU PhD '20), Tyler Treakle (REU student), and Phoebe Zarnetske (MSU SpaCE Lab PI):

Twardochleb, L. A., T. C. Treakle, and P. L. Zarnetske. (2020). Foraging strategy mediates ectotherm predator–prey responses to climate warming. Ecology. e03146. DOI:10.1002/ecy.3146. 

Further context for the video and study is below:

Climate change alters the survival of cold-blooded, predatory animals, because warming increases their metabolism, making them hungrier and forcing them to eat more in order to grow, survive, and reproduce. Warming could benefit predator species that are able to capture and eat more prey at higher temperatures, because these predators can grow faster and potentially increase their number of offspring. We used a series of experiments to explore which types of predator species could benefit from climate warming by eating more and growing faster. We expected that actively foraging predators (sharks are an example), would seek out and capture more prey at higher temperatures as their hunger increased, and that this would allow them to grow faster and benefit from climate warming. By contrast, we expected that sit-and-wait predators (snakes are an example) that remain in a fixed location while hunting would be harmed by climate warming. We expected that these predators would not be able to find more prey at higher temperatures and could starve as a result of increasing hunger. We tested our predictions with experiments at different temperatures from 10 to 35 ºC (cool to warm), in which we fed a species of crustacean zooplankton prey to two different insect predators, juvenile damselflies (a sit-and-wait predator) and juvenile backswimmers (an active predator). We video recorded these experiments and observed the number of prey that each predator ate and how much they grew at each temperature. We found that both the active and sit-and-wait predator consumed more prey and grew faster at high than low temperatures when they had access to unlimited numbers of prey. Our results also suggested, contrary to our expectations, that active predators may be more likely than sit-and-wait predators to starve as a result of climate warming if their prey populations decline. This is because active predators already have to eat more prey than sit-and-wait predators, and warming further increases their hunger, requiring that they eat even more to avoid starvation.