![]() This is supported by the fact that praying mantises are the only invertebrates known to have stereoscopic vision. ![]() This suggests that mantises use looming to avoid predators and stereopsis to catch prey. In addition, looming has been studied in the context of defensive responses and has not been implicated in prey capture so far. For motion-in-depth specifically, their sensitivity to looming has been studied in some detail ( Sato and Yamawaki, 2014 Yamawaki, 2011), but other cues have not been examined. ![]() Mantises are sensitive to multiple cues to depth including stereoscopic cues and motion parallax owing to self-motion ( Nityananda et al., 2016b Poteser and Kral, 1995 Rossel, 1983). When it comes to predation, they have an especially clear behaviour indicating their perception of depth – a predatory strike that involves a rapid extension of their forelimbs to capture prey, released only when prey is within catch range. Praying mantises are particularly interesting animals to consider. Much less is known about how insects, with their far simpler nervous systems, combine multiple cues and reconcile conflicts. The relative strength of the two cues depends on the precise stimulus and task for example, IOVDs dominate for stimuli with high speeds covering wide areas of the visual field, whereas changing disparity cues dominate for lower speeds in the central visual field ( Cormack et al., 2017 Czuba et al., 2011 Parker et al., 1996). These IOVDs have also been shown in humans to contribute to judgements of motion-in-depth ( Shioiri et al., 2000). For example, an object approaching along the midline would have a rightward velocity in the left eye and a leftward velocity in the right eye. Approaching objects would also have differing velocities in each eye. This changing disparity cue suffices to create a perception of motion-in-depth for human observers, even in the absence of other cues ( Cumming and Parker, 1994). Thus as an object approaches, the disparity between the two views changes. This disparity reflects the distance to an object. Stereoscopic disparity refers to the difference in the position of an object as seen by the two eyes. Two of the motion-in-depth cues that have received the most attention in humans are binocular: changing disparity and interocular velocity differences (IOVDs) ( Cormack et al., 2017). We conclude that mantises use stereopsis to detect depth but not motion-in-depth, which is detected via looming. Approach indicated by radial motion of a texture or expansion of a motion-defined edge, or by stereoscopic cues, all failed to elicit increased striking. Our results show that motion-in-depth does increase the probability of mantis strikes but only for the classic looming stimulus, an expanding luminance edge. We used our 3D insect cinema in a series of experiments to investigate the role of the stereoscopic cues mentioned above, as well as looming, in the perception of motion-in-depth during predatory strikes by the praying mantis Sphodromantis lineola. Although these have been studied in detail in humans, only looming responses have been well characterized in insects and we know nothing about the role of stereoscopic cues and how they might interact with looming cues. This can be achieved using several cues, including binocular stereoscopic cues such as changing disparity and interocular velocity differences, and monocular cues such as looming. This is explained in the same way as the image of the ship, except that the image is not inverted the variations in density may also act as a magnifying glass.Perceiving motion-in-depth is essential to detecting approaching or receding objects, predators and prey. There is a different type of mirage that is also described as looming, in which distant objects appear much nearer than they actually are. Evidence indicates that looming perception is not limited to the visual modality, but can occur due to auditory or even tactile stimuli. ![]() As the resulting image becomes increasingly larger on the perceiver's retina, i.e., when an object looms, there is an automatic physiological response to perceive the object as an approaching object or surface, instead of one that is stationary or receding. Looming occurs when an object begins moving closer to the eye. Looming is a term found in the study of perception, as it relates directly to psychology. ( November 2009) ( Learn how and when to remove this template message) Please help to improve this article by introducing more precise citations. This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations.
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