The Effects of Low Temperature Upon the Locomotor Activity Rhythm of Talitrus Saltator (Montagu) (Crustacea: Amphipoda)

1972 ◽  
Vol 57 (2) ◽  
pp. 393-399
Author(s):  
P. K. BREGAZZI
Keyword(s):  
Locomotor Activity ◽  
Low Temperature ◽  
Mode Of Action ◽  
Activity Rhythm ◽  
Inhibitory Factor ◽  
Locomotor Rhythm ◽  
Locomotor Activity Rhythm ◽  
Complete Cessation ◽  
Maximum Delay ◽  
Talitrus Saltator

1. Chilling Talitrus causes a complete cessation of locomotor activity and a delay in the appearance of successive activity peaks following return to normal temperatures. Maximum delay occurs if chilling begins during inactivity and is about equal to the duration of the chill. At other times the delay is less than the duration of the chill. 2. It is postulated that an inhibitory factor is concerned in the control of the locomotor rhythm of Talitrus, and a model is proposed to describe its possible mode of action.

Splitting of the locomotor activity rhythm in rats by exposure to continuous light

1983 ◽  
Vol 244 (4) ◽  
pp. R573-R576 ◽  
Author(s):  
Phyllis W. Cheung ◽  
Charles E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Female Rats ◽  
Locomotor Rhythm ◽  
Estrous Cycles ◽  
Locomotor Activity Rhythm ◽  
Active Portion ◽  
Free Running

Female rats exposed to low intensities (0.1–1.5 lx) of continuous light (LL), displayed regular estrous cycles and free-running circadian rhythms of locomotor activity. In most rats, as the intensity of LL was increased to >2.0 lx, components within the active portion (α) of the locomotor rhythm remained synchronized as the periodicity of the rhythm lengthened. However, in a few rats agr split into two components; one of which free-ran with a period shorter than 24 h, while the other free-ran with a period longer than 24 h. As soon as the two components became maximally separated they spontaneously rejoined. In most rats, estrous cycles ceased shortly after the intensity of LL was increased to >2.0 lx even though the locomotor activity rhythm retained its unsplit free-running nature. These observations suggest that the multiple oscillators that control the rhythms of locomotor activity and the estrous cycle are normally coupled to one another. In certain intensities of LL, these oscillators uncouple and free-run with different periodicities, a condition which causes estrous cycles to cease and sometimes produces a split locomotor activity rhythm. circadian rhythm; oscillators; estrous cycle Submitted on November 9, 1981 Accepted on October 11, 1982

The endogenous locomotor activity rhythm of four supralittoral peracarid crustace

1983 ◽  
Vol 63 (2) ◽  
pp. 481-492 ◽  
Author(s):  
John A. Williams
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Circadian Pattern ◽  
Crustacean Species ◽  
Emergence Pattern ◽  
Locomotor Activity Rhythm ◽  
Talitrus Saltator ◽  
Locomotor Rhythms ◽  
Endogenous Component ◽  
Periodogram Analysis

The ‘strength’ of the endogenous locomotor activity rhythm of four peracarid crustacean species, denned by the precision and persistence of the rhythm, was examined with particular reference to a ‘burrowing’ versus epifaunal supralittoral life-style. The ‘strength’ of the endogenous component of the activity rhythm was also illustrated using a modified periodogram analysis. In all species, the talitrid amphipods Talitrus saltator, Talorchestia deshayesi, Orchestra gammarella and the oniscoid isopod Ligia oceanica, the laboratory-monitored rhythm and the field emergence pattern displayed a nocturnal, circadian pattern with no clear evidence of any circa-tidal influence. The precision and particularly the persistence of the rhythm of the sand-shore burrowing species T. saltator and T. deshayesi are especially well developed, although a ‘strong’ endogenous component is present in the rhythm of all four species. The significance of the endogenous locomotor rhythms is considered with respect to the supralittoral ecology of the species.

scholarly journals The Effect of Perturbations in the Environmental Cycle of the Diurnal Rhythm of Activity of Periplaneta Americana L

1960 ◽  
Vol 37 (1) ◽  
pp. 154-163 ◽  
Author(s):  
JANET E. HARKER
Keyword(s):  
Locomotor Activity ◽  
Periplaneta Americana ◽  
Activity Rhythm ◽  
Neurosecretory Cells ◽  
Secretory Phase ◽  
Locomotor Rhythm ◽  
Locomotor Activity Rhythm ◽  
Transient Activity ◽  
Subsequent Phase ◽  
Three Stages

1. The locomotor activity rhythm of Periplaneta americana in alternating light and darkness is described as consisting of six stages. 2. The effect on the suboesophageal ganglion neurosecretory cycle of a change from light to darkness at each stage of the locomotor rhythm is described, and three stages in the neurosecretory cycle are recognized. 3. The effect on an established locomotor activity rhythm of a change to darkness at various times of day is described in terms of the immediate reaction of the animal and of the subsequent phase relations of the rhythm. 4. The phases of the activity rhythm are not reset if the environmental change occurs during the active period. The final positioning of the phases, when the onset of darkness occurs during the non-secretory phase of the neurosecretory cycle, is dependent upon the subsequent light conditions; transient activity peaks may appear before the stable position is reached. 5. The dependence of the neurosecretory cells on some other centre for the provision of some secretory substance, or precursor, is discussed.

scholarly journals Internal Factors Controlling the Suboesophageal Ganglion Neurosecretory Cycle in Periplaneta Americana L

1960 ◽  
Vol 37 (1) ◽  
pp. 164-170
Author(s):  
JANET E. HARKER
Keyword(s):  
Locomotor Activity ◽  
Room Temperature ◽  
Periplaneta Americana ◽  
Activity Rhythm ◽  
The Body ◽  
Suboesophageal Ganglion ◽  
Natural Conditions ◽  
Internal Factors ◽  
Locomotor Rhythm ◽  
Locomotor Activity Rhythm

1. Two interacting factors, both following a 24 hr. rhythm, are found to be concerned in the control of the locomotor activity rhythm of Periplaneta americana. 2. When the suboesophageal ganglion is chilled to 30°C., the rest of the body being kept at room temperature, the phases of the neurosecretory cycle are delayed for a period equivalent to the period of chilling. 3. A second cycle, which follows a 24 hr. rhythm, can act as a stimulus to the neurosecretory cycle if the latter is at a stage which responds to a stimulus. If the second cycle affects the neurosecretory cycle the phases of the latter are reset by the stimulus. The phases of the second cycle can be reset by a change from light to darkness while the suboesophageal ganglion is in the chilled state. It appears that the second cycle is immediately reset by the onset of darkness, regardless of the time at which this occurs. 5. The value to the animal, in its natural conditions, of the control of the locomotor rhythm by two interacting cycles is discussed.

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