Bristol scientists found that animals utilizing the most effective ways of resource hunting may die.
Today’s Behavioural Ecology discoveries explain why animals don’t always adopt the best search method.
How animals travel through their ecosystem, especially to get food, is a key biology subject that affects how they adapt to environmental change.
Numerous studies have shown that Lévy mobility, which involves long-distance travels between search regions and intense searches in one area, improves resource discovery. Many animals employ this movement.
Three-spined stickleback Wikimedia Commons
This study shows that prey employing Lévy motion are targeted twice as often as prey using Brownian motion, the movement of molecules in a gas and a baseline expectation.
“We show that this is because the predators prefer to target prey that are moving with straighter paths of motion, possibly because this makes the prey’s future position more predictable,” said Bristol School of Biological Sciences Professor Christos Ioannou.
Professor Ioannou’s team exploited simulated prey. They created a computer simulation of prey that are the same size, color, speed, and turn differently.
A transparent screen projected the footage to stickleback fish in an aquarium. This let fish observe prey and researchers record their selections.
“By using an experimental design that presents virtual prey on a screen to real predators, we can control everything about the prey and isolate the variable we’re interested in – here, movement – while also using real animals,” explained Professor Ioannou.
This study shows that prey animals may not always maximize resource discovery due to unknown costs. This may explain why some research indicated animals perform non-Lévy motion searches.
“Our study shows, for the first time, that animals using a common and very effective way of searching for resources may actually pay a cost of being more susceptible to predators,” he said.
We wish to examine stickleback prey for Levy or Brownian motion.
Our analysis predicts that prey animals would exhibit Lévy motion less often than apex predators.
Christos Ioannou et al. in Behavioural Ecology found that predatory fish prefer virtual prey with Lévy motion.