Predator sounds disrupt visual attention in jumping spiders

Abstract

Perception in one sensory modality can influence not only what animals attend to in another, but also whether animals increase their vigilance or remain engaged with ongoing sensory stimuli at all. Jumping spiders (Salticidae) are highly visual animals, but they are also alert to auditory cues. Previous work has shown that jumping spiders respond to the sound of the wingbeats of wasps, a potential predator, by freezing. Here, we examined whether wasp sounds influence eye movements, an indicator of visual attention. We used a custom-built eye tracker to measure the gaze direction of the movable, high-acuity principal eyes, and tested whether spiders would shift their gaze toward the location of a threat. In Experiment 1, when spiders were played the sound of a buzzing wasp, their retinas, initially at rest, immediately began sweeping rapidly back and forth, but were not directed toward the location of the sound. In Experiment 2, spiders scanning a salient prey stimulus (a cricket silhouette) with their principal eyes were simultaneously presented with a wasp sound and the appearance of a visual distractor. Compared to trials in which the same spiders were shown the distractor without sound, spiders were more likely to shift their gaze away from the cricket but were no more likely to redirect their gaze toward the distractor. Because acoustic cues from aerial predators may indicate immediate danger without providing reliable spatial information, orienting toward the wrong target may be costly under high uncertainty. Our results demonstrate that predator sounds do not spatially guide visual attention in jumping spiders, but instead disrupt attention to salient visual stimuli by increasing non-directed eye movements.