Responses of medulla neurons to illumination and movement stimuli in the tiger beetle larvae

Abstract

Intracellular responses of medulla neurons (second-order visual interneurons) have been examined in the tiger beetle larva. The larva possesses six stemmata on either side of the head, two of which are much larger than the remaining four. Beneath the cuticle housing the stemmata an optic neuropil complex occurs consisting of lamina and medulla neuropils. Response patterns of medulla neurons to illumination and moving objects varied from neurons to neurons. For movement stimuli black discs and a black bar were moved in the rostro-caudal direction above the larva. Comparison of responses to the discs and the bar suggested a spatial summation of responses in some neurons, and tuning to small objects in some neurons. The majority of neurons responded to objects moving at heights of 10 mm and 50 mm with the same discharge pattern. A few neurons, however, showed distance sensitivities responding with an increase of spike discharges to moving objects only at either of the two heights. Such distance sensitivities still remained in one-stemma larvae, three of the four stemmata being occluded. These data are discussed in relation to distinct visual behavior of the larva and with special reference to perception of the hunting range.

Response Properties of Visual Interneurons to Motion Stimuli in the Praying Mantis, Tenodera aridifolia

“…Small-field motion-sensitive cells have been reported in various insects (Collett, 1971;Olberg, 1981Olberg, , 1986Egelhaaf, 1985a, b, c;Okamura and Toh, 2001). Most of them, for example the FD cells in the fly (Egelhaaf, 1985b) and most of the TSDNs in the dragonfly (Olberg, 1986), are directionally selective, but SF neurons found in the present study did not show clear directional selectivity.…”

“…Most of them, for example the FD cells in the fly (Egelhaaf, 1985b) and most of the TSDNs in the dragonfly (Olberg, 1986), are directionally selective, but SF neurons found in the present study did not show clear directional selectivity. Not only in the mantis, but also in the tiger beetle larvae, the neurons responding to small moving objects are non-directionally selective (Okamura and Toh, 2001). The difference in directional selectivity may be due to whether the insects fly in the sky or walk on the ground during tracking an object.…”

Adult tiger beetles Cicindela gemmata modify their foraging strategy in different hunting contexts

“…While hunting, tiger beetles must not only measure their striking distance (Okamura & Toh, 2001) but also correct for their heading angle in order to minimize the time of pointing directly toward the prey (Noest & Wang, 2017). If a tiger beetle cannot grasp the prey with its mandibles in 1 attack (i.e.…”