The functional significance of mantis peering behaviour

Abstract

Abstract. The aim of this review is to explain the functional significance of mantis peering behaviour from an entomological perspective. First the morphological and optical features of the mantis compound eye that are important for spatial vision are described. The possibility that praying-mantises use binocular retinal disparity (stereopsis) and other alternative visual cues for determining distance in prey capture, are discussed. The primary focus of the review is the importance of peering movements for estimating the distance to stationary objects. Here the following aspects are examined: (1) Direct evidence via object manipulation experiments of absolute distance estimation with the aid of self-induced retinal image motion; (2) the mechanism of absolute distance estimation (with the interaction of visual and proprioceptive information); (3) the range of absolute and relative distance estimation; (4) the influence of target object features on distance estimation; and (5) the relationship between peering behaviour and habitat structures, based on results of studies on three species of mantis.

Unilateral range finding in diving beetle larvae

“…This distance cue is particularly effective if an animal has tight control over its own translational movements while viewing stationary objects against a structured background. This frequently is the case for peering movements (Collett, 1978;Kral, 2012). For example, a praying mantis will translate its head horizontally prior to striking a stationary target.…”

“…For example, a praying mantis will translate its head horizontally prior to striking a stationary target. Exaggerating their image translation can lead to systematic strike distance errors (Kral, 2012). Could T. marmoratus larvae therefore obtain motion parallax cues while approaching their prey?…”

“…This is because object movement elicits confounding translational patterns on the retina, leading to unresolvable ambiguities. Presumably for this reason even mantises, which are well known to rely on motion parallax for stationary objects, use other strategies for range finding if presented with moving objects (for a review, see Kral, 2012).…”

“…The importance of the last two mechanisms has been demonstrated in multiple species such as mantids (Kral, 2012;Poteser and Kral, 1995;Rossel, 1983), locusts (Collett, 1978;Kral and Poteser, 1997;Sobel, 1990) and dragonflies (Olberg et al, 2005). Using an experimental arena with a well-controlled artificial stimulus that confounded motion parallax cues, we first tested whether T. marmoratus larvae indeed are effective in gauging the distance of a target from cues other than simply image size.…”

Multitasking in an eye: How the unusual organization of the principal larval eyes of Thermonectus marmoratus allows for far and near vision and might aid in depth perception

“…In insects, only a few such mechanisms are well described (Collett and Harkness, 1982). Among the most common and best known is motion parallax, the importance of which has been highlighted in mantids (Kral, 2012), wasps (Zeil, 1993), locusts (Collett, 1978), grasshoppers (Kral, 2009), crickets (Goulet et al, 1981) and bees (Srinivasan et al, 1989). Other somewhat more controversial range-finding mechanisms are based on binocular cues (Kral, 1999;Kral, 2012), such as stereopsis (Rossel, 1983).…”