Global study reveals why some animals shine bright and others disappear in plain sight
A European stonechat (Saxicola rubicola) has caught an orange and black patterned Glanville fritillary butterfly (Melitaea cinxia) i. The butterfly's warning coloration may mean that it is not suitable for consumption.
© Stanislav Harvančík
To the point
- Conspicuous or camouflaged: Animals use conspicuous colours or camouflage to protect themselves from predators. A new study examines the factors that influence these decisions.
- Influence of the environment: The predator community and habitat influence whether camouflage or warning colours are more successful.
- Results: In areas with strong competition among predators, camouflage was more effective, while in bright habitats, warning colours worked better.
Why do some animals warn predators away with bold colours while others rely on camouflage to stay hidden? A major new study, involving ecologists worldwide including Hannah Rowland, former Group Leader at the Max Planck Institute for Chemical Ecology and now University of Liverpool, has investigated what drives the evolution of these contrasting survival strategies. Together with Renan Janke Bosque, Hannah Rowland contributed crucial data from fieldwork in Brazil.
The global experiment spanned six continents and used more than 15,000 artificial prey in three colour patterns: the classic orange-and-black warning signal, a dull brown camouflage, and an unusual bright blue-and-black design. The results show that context is key. Predator communities, habitats, and prey familiarity all influence whether camouflage or warning colours offer the best protection.
The study found that predator community had the greatest impact. In areas with high competition among predators, camouflage was more successful, because predators were likely more willing to risk attacking potentially toxic prey. But cryptic strategies didn't always work. In bright habitats, camouflaged prey were more visible and attacked more often than prey with classic warning colours. And where camouflage was common, predators became better at spotting it, reducing its effectiveness.
Overall, the findings highlight how multiple factors interact to shape the global distribution of antipredator colour strategies. The researchers say this work provides new insights into the evolution of two of the most widespread animal defences: camouflage and warning signals. "This is the best of team and collaborative science - working across continents to understand a fundamental aspect of biodiversity and evolution," said Hannah Rowland.
