Seen in part, feared in full: conditional visibility enhances eyespot defenses without experience-dependent decay

Predation is a significant ecological pressure that shapes species
evolution and community dynamics. Eyespots, as common anti-predator
signals, are widely observed in various animals, particularly among
lepidopteran species. These markings function by either mimicking the eyes
of natural predators or acting as conspicuous warning signals to deter
potential threats. However, eyespot effectiveness depends on environmental
context (e.g., microhabitat structure) and predator experience. Here, we
examined how partial eyespot concealment and short-term predator
experience influence early-stage predation behavior using artificial prey
and domestic chicks. We used artificial prey and manipulated eyespot
visibility across microhabitat conditions. Our results show that
partially occluded eyespots consistently delayed predation, with chicks
taking longer to approach and exhibiting prolonged hesitation compared to
prey with fully visible or absent eyespots. Short-term experience did not
alter these behavioral responses, indicating that immediate learning plays
a limited role in modulating reactions to salient deceptive signals.
Together, these findings demonstrate that the concealment of the eyespots
themselves, rather than habitat complexity alone which produces a
measurable deterrent effect, likely through a combination of neophobia
toward conspicuous stimuli and eye-mimicry processes. Our study highlights
how microhabitat-mediated visibility shapes the functioning of visual
defenses and offers new insight into the ecological and perceptual factors
influencing the evolution of eyespots in avian predator–prey interactions.