A Visually Induced Switch in Mode of Locomotion of a Spider

1997 ◽  
Vol 52 (1-2) ◽  
pp. 124-128 ◽  
Author(s):  
Axel Schmid
Keyword(s):  
Behavioral Change ◽  
Prey Capture ◽  
Complete Darkness ◽  
Cupiennius Salei ◽  
Locomotion Compensator ◽  
Visual Inputs ◽  
Sensitivity Range ◽  
Locomotion Pattern ◽  
Substrate Vibrations ◽  
Spider Cupiennius Salei

Abstract The spider Cupiennius salei Keys. (Araneae, Ctenidae) is a nocturnal hunter living on monocotyledones. It does not build webs for prey capture. During the day it remains in its retreat and during dusk it begins to hunt for prey or to search for mates. C. salei is well equipped with mechanosensory systems to detect air- or substrate- borne vibrations elicited by prey or predators. If none of them produce either air movements or substrate vibrations, and the light intensity is below the threshold (0.1 lx), the animal is virtually " blind" . There­ fore a hypothetical, additional sensory input should exist, which is used only in complete darkness. The animal was tested on a locomotion compensator were it performs constant walks towards a visual target. Three different light intensities were used (bright 200 lx, dim 0.1 lx, and dark at 950 nm, which is outside the spectral sensitivity range of the animal). At bright and dim illumination the animal walked in the alternating tetrapod gait towards the target. In complete " darkness" the walk was no longer directed and the animal changed its gait and continued walking on only six legs using the first pair as guide-sticks. If the first pair is missing, the second cannot replace this function. This shows a twofold use of the first pair o f legs as ordinary walking legs and as guide-sticks or " antennae" . Therefore one can assume that visual input causes a behavioral change, which can not be explained by a fixed locomotion pattern but by adaptive changes caused by visual inputs.

THE QUALITY OF VISION IN THE CTENID SPIDER CUPIENNIUS SALEI

1992 ◽  
Vol 164 (1) ◽  
pp. 227-242 ◽  
Author(s):  
M. F. LAND ◽  
F. G. BARTH
Keyword(s):  
Predator Avoidance ◽  
Prey Capture ◽  
Cupiennius Salei ◽  
Quality Of Vision ◽  
Visual Behaviour ◽  
Similar Range ◽  
Retinal Resolution ◽  
Spider Cupiennius Salei ◽  
Median Eyes

Much is known about the mechanosensory behaviour of the spider Cupiennius Keyserling, but much less about its visual capabilities. In this study the quality of the optical image, the retinal resolution and the fields of view were assessed for each of the four pairs of eyes. The image is of good quality in all eyes. The principal (antero-median) eyes lack a tapetum and have an inter-receptor angle of 2.9°. The three secondary eyes (antero-lateral, postero-median and posterolateral) all have ‘gridiron’ tapeta with receptors arranged in rows. The angular separations (along rows × between rows) are 3.6° × 9.3°, 0.9° × 2.3° and 1.0° × 3.0°, respectively. Although the disposition of eyes on the head is similar to that of pisaurid spiders, all other features of the eyes, including the sizes and shapes of the fields of view, resemble those of lycosid spiders. The peripheral visual system of Cupiennius can thus, in principle, support a similar range of visual behaviour to that of lycosids, which includes prey capture, predator avoidance and courtship.

scholarly journals Airflow elicits a spider's jump towards airborne prey. II. Flow characteristics guiding behaviour

2013 ◽  
Vol 10 (82) ◽  
pp. 20120820 ◽  
Author(s):  
Christian Klopsch ◽  
Hendrik C. Kuhlmann ◽  
Friedrich G. Barth
Keyword(s):  
Flow Field ◽  
Prey Capture ◽  
Flow Characteristics ◽  
Companion Paper ◽  
Phase Iii ◽  
Airflow Velocity ◽  
Flow Sensors ◽  
Cupiennius Salei ◽  
Capture Reaction ◽  
Substrate Vibrations

When hungry, the wandering spider Cupiennius salei is frequently seen to catch flying insect prey. The success of its remarkable prey-capture jump from its sitting plant into the air obviously depends on proper timing and sensory guidance. In this study, it is shown that particular features of the airflow generated by the insect suffice to guide the spider. Vision and the reception of substrate vibrations and airborne sound are not needed. The behavioural reactions of blinded spiders were examined by exposing them to natural and synthetic flows imitating the fly-generated flow or particular features of it. Thus, the different roles of the three phases previously identified in the fly-generated flow and described in the companion paper could be demonstrated. When exposing the spider to phase I flow only (exponentially increasing flow velocity with very little fluctuation and typical of the fly's approach), an orienting behaviour could be observed but a prey-capture jump never be elicited. Remarkably, the spider reacted to the onset of phase II (highly fluctuating flow) of a synthetically generated flow field with a jump as frequently as it did when exposed to natural fly-generated flows. In all cases using either natural or artificial flows, the spider's jump was triggered before its flow sensors were hit by phase III flow (steadily decreasing airflow velocity). Phase III may tell the spider that the prey has passed by already in case of no prey-capture reaction. Our study underlines the relevance of airflow in spider behaviour. It also reflects the sophisticated workings of their flow sensors (trichobothria) previously studied in detail. Presumably, the information contained in prey-generated airflows plays a similar role in many other arthropods.

Intracellular characterization of identified sensory cells in a new spider mechanoreceptor preparation

1994 ◽  
Vol 71 (4) ◽  
pp. 1422-1427 ◽  
Author(s):  
E. A. Seyfarth ◽  
A. S. French
Keyword(s):  
Sensory Neurons ◽  
Action Potentials ◽  
Lucifer Yellow ◽  
Sense Organ ◽  
Sensory Cells ◽  
Cupiennius Salei ◽  
Bursting Neuron ◽  
Sensory Structures ◽  
Spider Cupiennius Salei

1. We have developed an isolated mechanoreceptor-organ preparation in which the intact sensory structures are available for mechanical stimulation and electrical recording. The anterior lyriform slit sense organ on the patella of the spider, Cupiennius salei Keys., consists of seven or eight cuticular slits, each innervated by a pair of large bipolar sensory neurons. The neurons are fusiform, and the largest somata are < or = 120 microns long. The innervation of the organ was characterized by light microscopy of neurons backfilled with neuronal tracers. Intracellular recording was used to measure the passive and active electrical properties of the neurons, in several cases followed by identification with Lucifer yellow injection. Both neurons of each pair from one slit responded with action potentials to depolarization by a step current injection. Approximately half of the sensory neurons adapted very rapidly and generated only one or two action potentials in response to a sustained depolarizing step, while a second group produced a burst of action potentials that adapted to silence in approximately 1 s or less. Recordings from identified neuron pairs indicated that each pair consists of one rapidly adapting and one bursting neuron. Measurements of cell membrane impedances and time constants produced estimates of neuronal size that agreed with the morphological measurements. This new preparation offers the possibility of characterizing the mechanisms underlying transduction and adaptation in primary mechanosensory neurons.

Biochemistry, toxicology and ecology of the venom of the spider Cupiennius salei (Ctenidae)

Toxicon ◽  
2004 ◽  
Vol 43 (5) ◽  
pp. 543-553 ◽  
Author(s):  
Lucia Kuhn-Nentwig ◽  
Johann Schaller ◽  
Wolfgang Nentwig
Keyword(s):  
Cupiennius Salei ◽  
Spider Cupiennius Salei
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