Sensory control of leg movement in the stick insect Carausius morosus

1977 ◽  
Vol 25 (2) ◽  
pp. 61-72 ◽  
Author(s):  
U. B�ssler
Keyword(s):  
Stick Insect ◽  
Sensory Control ◽  
Carausius Morosus ◽  
Leg Movement

scholarly journals Which Parameters Control the Leg Movement of a Walking Insect?: I. Velocity Control during the Stance Phase

1985 ◽  
Vol 116 (1) ◽  
pp. 343-355 ◽  
Author(s):  
H. CRUSE
Keyword(s):  
Stance Phase ◽  
Stick Insect ◽  
Experimental Results ◽  
Velocity Control ◽  
Carausius Morosus ◽  
Different Types ◽  
Leg Movement ◽  
Position Servo

In treadwheel walking, the front and middle legs of the stick insect (Carausius morosus) propel the wheel, while the hind legs exert very little force and can even decelerate the wheel. This result is compared with observations on the function of the legs in different walking situations. Several hypotheses assuming different types of position servo-mechanisms have been proposed in the literature on the control of leg movement during walking in insects. The experimental results support none of these hypotheses. Instead, they indicate that velocity rather than position is the variable controlled during the stance phase.

scholarly journals Which Parameters Control the Leg Movement of a Walking Insect?: II. The Start of the Swing Phase

1985 ◽  
Vol 116 (1) ◽  
pp. 357-362 ◽  
Author(s):  
H. CRUSE
Keyword(s):  
Stance Phase ◽  
Stick Insect ◽  
Swing Phase ◽  
Feedback Mechanism ◽  
Threshold Values ◽  
Forward Movement ◽  
Carausius Morosus ◽  
Position Feedback ◽  
Leg Movement ◽  
Leg Position

When a stick insect (Carausius morosus) walks on a treadwheel with one leg standing on a platform beside the wheel, this leg can be considered to perform a prolonged stance phase. To elicit a swing phase in this situation, both load and position must decline below definite threshold values. The swing phase can be elicited when - given a sufficiently posterior leg position - a central temporal signal initiates a small forward movement, and this is followed by a decrease of load. It is possible for signals from the next posterior leg to change the position threshold at which the swing phase can be started, but these commands do not influence the force values during the stance phase. Thus position is one parameter used for the decision to end the stance phase. But it does not serve as a signal for a position feedback mechanism controlling leg movement during the stance phase.

Control of reflex reversal in stick insect walking: effects of intersegmental signals, changes in direction, and optomotor-induced turning

2012 ◽  
Vol 107 (1) ◽  
pp. 239-249 ◽  
Author(s):  
Katja Hellekes ◽  
Eric Blincow ◽  
Julia Hoffmann ◽  
Ansgar Büschges
Keyword(s):  
Nervous System ◽  
Sensory Feedback ◽  
Stick Insect ◽  
Chordotonal Organ ◽  
Sense Organs ◽  
Carausius Morosus ◽  
Output Change ◽  
Reflex Reversal ◽  
Leg Movement ◽  
First Time

In many animals, the effects of sensory feedback on motor output change during locomotion. These changes can occur as reflex reversals in which sense organs that activate muscles to counter perturbations in posture control instead reinforce movements in walking. The mechanisms underlying these changes are only partially understood. As such, it is unclear whether reflex reversals are modulated when locomotion is adapted, such as during changes in walking direction or in turning movements. We investigated these questions in the stick insect Carausius morosus, where sensory signals from the femoral chordotonal organ are known to produce resistance reflexes at rest but assistive movements during walking. We studied how intersegmental signals from neighboring legs affect the generation of reflex reversals in a semi-intact preparation that allows free leg movement during walking. We found that reflex reversal was enhanced by stepping activity of the ipsilateral neighboring rostral leg, whereas stepping of contralateral legs had no effect. Furthermore, we found that the occurrence of reflex reversals was task-specific: in the front legs of animals with five legs walking, reflex reversal was generated only during forward and not backward walking. Similarly, during optomotor-induced curved walking, reflex reversal occurred only in the middle leg on the inside of the turn and not in the contralateral leg on the outside of the turn. Thus our results show for the first time that the nervous system modulates reflexes in individual legs in the adaptation of walking to specific tasks.

Sex chromosomes and origin of males and sex mosaics of the parthenogenetic stick insect Carausius morosus Br.

Chromosoma ◽  
1980 ◽  
Vol 79 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Laas P. Pijnacker ◽  
Margriet A. Ferwerda
Keyword(s):  
Sex Chromosomes ◽  
Stick Insect ◽  
Carausius Morosus

Hormonal Control of the Malpighian Tubules of the Stick Insect, Carausius Morosus

1970 ◽  
Vol 52 (3) ◽  
pp. 653-665 ◽  
Author(s):  
DIANA E. M. PILCHER
Keyword(s):  
Stick Insect ◽  
Hormonal Control ◽  
The State ◽  
Malpighian Tubules ◽  
Suboesophageal Ganglion ◽  
Carausius Morosus ◽  
Corpora Cardiaca ◽  
Diuretic Hormone ◽  
The Brain

1. Urine secretion by isolated Malpighian tubules of Carausius is accelerated by a diuretic hormone which can be extracted from the brain, corpora cardiaca and suboesophageal ganglion. 2. The level of this hormone in the haemolymph varies according to the state of hydration of the insect. 3. The hormone is inactivated by the tubules, and a mechanism is proposed whereby the tubules might be controlled by the hormone in vivo.

Memoirs: The Embryonic Development of the Stick-Insect, Carausius morosus

1936 ◽  
Vol s2-78 (311) ◽  
pp. 487-511
Author(s):  
A. J. THOMAS
Keyword(s):  
Embryonic Development ◽  
Stick Insect ◽  
Malpighian Tubules ◽  
Germ Band ◽  
Ventral Plate ◽  
Carausius Morosus ◽  
Gut Epithelium ◽  
Cleavage Nucleus ◽  
Endodermal Cells ◽  
Late Stages

1. The maturation of the egg takes place in the ovarian tube, and is immediately followed by the formation of the cleavagenucleus and its division into many nuclei. 2. The entire products of the cleavage-nucleus migrate to the surface to form the blastoderm. Cleavage of the yolk was not observed even in late stages. Yolk-cells are absent when the blastoderm is being formed. 3. Primitive endodermal cells are proliferated from the middle of the germ-band, and form a membrane between the germ-band and the yolk. The membrane is present only in embryonic stages; some of the cells proliferated wander into the yolk and act as vitellophags. 4. Mesoderm is formed by proliferation of cells from the ventral plate. It is preceded by the formation of a shallow gastrular furrow, and from the bottom of this furrow proliferation takes place. The mesoderm becomes arranged in segmental masses. 5. Two masses of cells proliferated at the anterior and posterior ends of the germ-band are shown to be the endodermal rudiments from which the mid-gut epithelium is formed. The invaginations of the stomodaeum and proctodaeum grow against these masses and carry parts of the proliferating areas near their blind ends. It is shown that the various methods of mid-gut formation which have been described could be reconciled with the process described in Carausius. 6. The hinder end of the mid-gut is flanked by two plates of ectoderm which are forward extensions of the proctodaeum. Into these extensions the Malpighian tubules open, and, as their histology is identical with that of these extensions and widely different from that of the mid-gut, these tubules must be ectodermal in nature. 7. The formation of the amnion and serosa are described.

Experiments on blocking and unblocking of first meiotic metaphase in eggs of the parthenogenetic stick insect Carausius morosus Br. (Phasmida, Insecta)

Development ◽  
1976 ◽  
Vol 36 (2) ◽  
pp. 383-394
Author(s):  
L. P. Pijnacker ◽  
M. A. Ferwerda
Keyword(s):  
Interphase Nucleus ◽  
Stick Insect ◽  
Meiotic Metaphase ◽  
Anterior Region ◽  
Egg Cell ◽  
Metaphase Chromosomes ◽  
Carausius Morosus ◽  
Cytoplasmic Factors ◽  
Activating Agent ◽  
Nuclear Behaviour

The eggs of the parthenogenetic stick insect Carausius morosus, which remain arrested in first meiotic metaphase until oviposition, must be activated in order to develop. The activating agent is oxygen from the air, which enters the egg cell through the micropyle. An exposure shorter than one minute is sufficient to release the blockage. In non-activated (micropyle-less) eggs the first metaphase chromosomes either degenerate or change into an interphase nucleus. This nucleus polyploidizes by endoreduplication, and then either degenerates or multiplies by amitosis. Similarly more generations of nuclei may arise resulting in a chaotic development. These nuclei survive better in the anterior region of the egg. The question of whether the cytoplasmic factors which control nuclear behaviour, also operate in eggs of C. morosus is discussed.

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