Bright colors can work better than camouflage to evade predators

Bird attacks on paper moths show how nature sets the rules for survival. In a global study, scientists tested how different color strategies help prey avoid becoming lunch.

The team set out 15,018 paper moth models across 21 forests on six continents and watched which ones got pecked. They used three types: brown for blending in, a classic orange-and-black warning pattern, and an unusual turquoise-and-black set.

Global study of prey survival

The work was led by Dr. Iliana Guzman in the School of BioSciences at the University of Melbourne (UM). The design allowed the group compare how hiding and warning play out under real predator pressure in different places.

“Our findings showed there is no single best color strategy to deter predators, but that context is critical,” said Dr. Guzman.

Predators, not latitude or season, did the heavy lifting in deciding which strategy worked. Where birds competed strongly for food, the first attacks landed more often on the bold warning targets, while the brown moths enjoyed an early reprieve.

“In environments where predators are competing intensely for food, they are more likely to risk attacking prey that might be dangerous or distasteful. Hence, we saw that camouflage worked best in areas with lots of predation,” said Dr. Guzman.

Predator competition drives color survival

Across animals, two main strategies shape survival. Camouflage hides prey by blending into the background, while aposematism does the opposite – using bright colors to advertise that a creature is toxic or dangerous.

These aren’t competing tactics so much as complementary tools, each paying off under different mixes of predator behavior, prey community structure, and local lighting.

When many predator species share the same habitat and food runs scarce, risk-taking rises. Birds in these conditions often sample unfamiliar prey despite warning colors.

That behavior carries another consequence: because each predator encounters the same pattern less often, the process of learning to avoid new warning signals slows, delaying the protection such colors usually provide.

Camouflage hides, colors warn

Warning colors get safer as more species use them. This echoes positive study results in the wild, where predators avoid common warning signals more than rare ones.

This process is called frequency dependent selection (FDS), which means the value of a trait depends on how common it is. Warning signals often get safer as they spread, while rare signals may be tested more.

Familiarity cuts both ways for hiding. If a forest holds many cryptic insects, birds refine their search behavior faster, and the payoff from blending in shrinks.

Predators learn color signals

Predators do not just react, they learn. Many birds build a search image, a mental template of what prey looks like, and use it to scan more efficiently.

That learning makes abundance matter. When brown, bark matched prey are everywhere, the search image for that look gets sharper, which raises the hit rate on camouflaged prey over time.

Bright light exposes prey

Lighting changes what predators can resolve. Under brighter conditions, edges and contrasts pop, and the benefits of blending in fall.

Background complexity matters too. Field experiments with birds and people show that cluttered bark can mask cryptic targets, while simple bark exposes them.

Bright signals hold steady

The performance of classic orange-and-black warnings remained relatively stable across sites.

That stability fits with what we know about signal design: high-contrast patterns are easy to notice, remember, and generalize.

Turquoise-and-black signals behaved differently. They helped early in some places but lost protection once birds learned that the new look did not come with a bad taste.

The survival of signals

Camouflage can fail when lighting no longer matches the pattern it was designed for. Modeling work on countershading shows that detection rises quickly once illumination shifts away from a prey’s built-in design. By contrast, bright warning colors rely less on such precise matches.

Their bold contrasts remain effective across a wide range of light conditions, which helps explain their reliability.

The evolutionary stakes are clear: camouflage pays off early in dim habitats or under heavy competition, but it becomes fragile as predators learn or as camouflaged prey accumulate.

Warning signals take an initial cost when predators sample boldly, but they retain their value once learning sets in. That contrast in durability can determine which strategy persists across many generations.

Changing predators tilt balance

If predator communities shift with land use or climate, the balance between hiding and warning can tilt quickly. That makes camouflage especially sensitive to change. It also hints at a broader pattern in nature.

Strategies that rely on predator learning and community context can flip as environments change, which can ripple through food webs.

No single color defense wins everywhere. The right choice depends on who is hunting, who else is around, and how the scene is lit. Simple rules of perception and learning explain much of the map. Evolution uses those rules, often in predictable ways, to set how animals look.

The study is published in the journal Science.

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