Which type of coloration offers prey the best protection from predators? An international team of scientists, including zoologists from the Faculty of Science, Charles University, used 15,000 artificial moths deployed in forests across six continents to determine whether conspicuous warning coloration or subtle camouflage is more effective. The results showed that no single strategy guarantees success - outcomes depend on environmental conditions, community composition, and predator behaviour.
Why do some animals use bright colours to warn off predators while others opt to camouflage themselves to avoid attack? To find out more, ecologists from around the world have collaborated on a major new study looking at what has led to the evolution of one strategy over another.
Dr Iliana Medina, from the University of Melbourne, and Dr William Allen, from Swansea University led a global experiment across six continents using more than 15,000 artificial prey in three different colours - a classic warning pattern of orange and black, a dull brown that blends in, and an unusual bright blue and black.
Several researchers from Charles University also made a significant contribution to the study, notably Alice Exnerová, Klára Daňková, Anita Szabó, Kateřina Hotová-Svádová, and Marie Truhlářová (Department of Zoology, Faculty of Science, Charles University), Tomáš Albrecht (Faculty of Science, Charles University and Institute of Vertebrate Biology, Czech Academy of Sciences), and Jan Raška (Faculty of Science, Charles University and Czech University of Life Sciences Prague).
From a biogeographical perspective, the inclusion of two Afrotropical sites was particularly important, especially Mt. Cameroon, where the experiment was carried out by the team of scientists and students from the Department of Zoology at Charles University. This work builds on a long-term research tradition in Cameroon, led by teams from Charles University and the Institute of Vertebrate Biology of the Czech Academy of Sciences.
The findings, which have just been published in Science, reveal that when it comes to deterring predators, context is crucial and several factors play a part in determining whether a camouflage or warning strategy works best.
Lead author Dr Allen said: “For a long time, scientists have wondered why some animals use one defence over the other – and the answer turns out to be complicated. The predator community, prey community and habitat are all influential. This helps explain why we see camouflaged and warning coloured animals all over the world”
The study discovered the predator community had the biggest impact on which prey colour was most successful. The team’s results support the idea that when predators compete intensely for food, they are more likely to risk attacking prey that might be dangerous or distasteful. Hence, camouflage worked best in areas with lots of predation.
But, being cryptic doesn’t always work. In bright environments, camouflaged prey was more visible than in darker environments and was attacked more than prey with classic warning colours. Familiarity with prey using different colour strategies is also important - in places where cryptic prey is abundant, hiding becomes less effective, as predators are better at looking for camouflage prey.
Overall the results showed how multiple mechanisms determine which strategy is more advantageous in a particular circumstance.
Dr Medina added: “Some questions in ecology involve such a wide range of variables that only global collaboration and replication can bring us closer to understanding how nature works. It was a pleasure to work with such a diverse group of colleagues who made this research possible”.
The researchers say their findings will help now build better understanding of the evolution and global distribution of the most common antipredator colour strategies in animals.
Read the paper Global selection on insect antipredator coloration in full: https://www.science.org/doi/10.1126/science.adr7368
A more detailed popular article on this topic can be found here: https://theconversation.com/warn-hide-or-stand-out-how-colour-in-the-animal-world-is-a-battle-for-survival-265670