Animals with high-contrast patterns are often thought to become more conspicuous when they move. More recently, studies have shown otherwise: high-contrast patterns can blur when an animal moves quickly enough through a strategy known as flicker fusion camouflage. However, there is limited empirical evidence for this notion. Here, we tested for the effectiveness of this strategy using the jumping spider (Menemerus bivittatus) and computer-generated stimuli of different patterns (i.e. black, grey, thin and vertically striped, thick and vertically striped, horizontally striped, and background matching) moving at three speeds. To understand how patterns can be used to exploit the visual constraints of the viewer, jumping spiders were also subjected to three different eye-masking treatments (i.e. unmasked, antero-median eyes (AME)-masked, and antero-lateral eyes (ALE)-masked), and their responses to stimuli were recorded. Our results showed that stimulus speed, pattern, and eye-masking significantly affected jumping spider responses. Jumping spiders generally showed lower responses when stimulus speed was fast. Compared to the grey stimuli, thin and vertically striped stimuli elicited higher responses for unmasked spiders. ALE-masked spiders responded less than unmasked and AME-masked spiders. However, ALE-masked and AME-masked spiders had low responses to the striped stimuli at high speeds. Taken together, our findings suggest that faster stimulus speeds may effectively exceed the flicker fusion frequency threshold of jumping spiders so that salticids may be unable to resolve the moving thin striped patterns, thus supporting for the flicker fusion camouflage hypothesis.
The Flicker Fusion Camouflage Effect in Jumping Spiders
Abstract ID: 189
Event: The 3rd AsiaEvo Conference
Topic: The evolution of invertebrate sensory ecology and behaviours
Presenter Name: Min Tan