Clock-Controlled Orientation in Space

Wallraff, Hans Georg

doi:10.1007/978-1-4615-6552-9_16

Cited by 8 publications

(7 citation statements)

References 45 publications

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“…However, the moon also presents some theoretical difficulties in its use as a chronometrically based orientation reference: it is not always visible during the synodic cycle, it is not always visible at the same hour and at the same azimuth, and it does not always present the same shape. These characteristics, together with the fact that among invertebrates a chronometrically compensated lunar orientation has been shown only in some species of sandhoppers (51,(68)(69)(70)(71)(72), has produced a great deal of scepticism towards the results achieved (see 73,74).…”

Section: The Moon Compassmentioning

confidence: 99%

Activity rhythms and orientation in sandhoppers CRUSTACEA AMPHIPODA

Ugolini

2003

Front Biosci

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The aim of the present review is to combine knowledge of locomotor activity rhythms with that of compass orientation in littoral arthropods. Talitrid amphipods (the sandhoppers) represent a good biological model in the fields of animal orientation and biological rhythms. The paper examines the activity rhythms of different species of sandhoppers (mainly Talitrus saltator), as well as the chronometric mechanisms of compensation for the apparent motion of the sun and moon that these animals use in zonal recovery based on the two astronomical cues. The two chronometric mechanisms seem to be independent of each other and to operate throughout the 24-hour period. The speed of the chronometric mechanism of solar compensation appears to be related to the hours of light and is entrained by the same stimulus (light-dark alternation) that controls the circadian activity rhythm. Therefore, it is probable that in T. saltator the same mechanism regulates both the circadian locomotor activity and the solar compensation.

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Section: The Moon Compassmentioning

confidence: 99%

Activity rhythms and orientation in sandhoppers CRUSTACEA AMPHIPODA

Ugolini

2003

Front Biosci

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“…Finally, the position of the sun could be utilized for twilight detection. We know that many animals can use the position of the sun for time-compensated sun-compass orientation (123), but whether this information is also used by mammals to entrain circadian systems remains a mystery. For this radiance detection task, topographic mapping, would be required to determine the position of the sun-perhaps in this way the "classical" visual system does contribute to photoentrainment.…”

Section: Light and The Circadian System Of Mammalsmentioning

confidence: 99%

Twilight Times: Light and the Circadian System

Roenneberg

Foster

1997

Photochem & Photobiology

308

203

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Whose twilights were more clear, than our mid-day.John Donne (1571-1631) Of the progress of the soul THE CIRCADIAN CLOCKThe spatial and temporal features of the environment have provided the abiotic selection pressures that have shaped the evolution of life on earth. We are accustomed to accept that the spatial world offers specialized niches. However, we rarely consider that the temporal structure of our planet offers similar opportunities. Most organisms have evolved specializations that allow them to exploit their environment in terms of both space and time, and this demands that individuals have an endogenous representation of these environmental features. We know surprisingly little about the endogenous representation of space, but in recent years an understanding of how organisms build a representation of their temporal world has begun to emerge.Organisms do not merely respond to their environment, they also have the capacity to adjust physiology and behavior in anticipation of changing environmental conditions. In a competitive world, "being prepared" offers a great selective advantage. It takes considerable time to bring about the complex realignments of physiological systems that permit an optimal expression of different behavioral states (e.g. activity and rest or exploitation of temporally restricted resources). By fine-tuning physiology in advance of the changing conditions, an organism can be ready to exploit the changed conditions to its best advantage.At the heart of the biological machinery that "creates" a day within us is a biological or Circadian clock. In mammals, for example, this resides within a small paired nucleus in the brain located above the crossing of the optic nerves, the suprachiasmatic nuclei or SCN.? The neuronal activity of this nucleus continues to oscillate with a 24 h rhythmicity

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“…In addition, that study revealed both the innate component of the mechanism and its independence of non-chronometric orientating factors. However, since its discovery in talitrids , lunar orientation has been the subject of heated debate (Enright 1961(Enright , 1972; see also Wallra¡ (1981) for a review). This is mainly due to the fact that the chronometric part of the lunar compass must deal with signi¢cant variations of the moon during the lunar month (e.g.…”

Section: Introductionmentioning

confidence: 99%

Moon and sun compasses in sandhoppers rely on two separate chronometric mechanisms

Ugolini

Melis

Innocenti

et al. 1999

Proc. R. Soc. Lond. B

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The relationship between the chronometric system of compensation for the apparent movement of the sun and that for the moon has been the subject of several, never proven, hypotheses. Our studies on sandhoppers have demonstrated that the chronometric mechanism of the moon compass is separate from that of the sun compass. They show (i) that a period of seven days in constant darkness has no in£uence on the capacity for orientation, either solar or lunar, and indicates the presence of one or more continuously operating timing mechanisms; (ii) that two di¡erent shifts in the light^dark phase have no e¡ect on the chronometric mechanism of lunar orientation, but they do a¡ect that of solar orientation; and (iii) that exposure to an arti¢cial moon delayed by seven days with respect to the natural cycle causes the expected change in the mean direction of individuals tested under the natural moon, but not of those tested under the sun.

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Clock-Controlled Orientation in Space

Cited by 8 publications

References 45 publications

Activity rhythms and orientation in sandhoppers CRUSTACEA AMPHIPODA

Activity rhythms and orientation in sandhoppers CRUSTACEA AMPHIPODA

Twilight Times: Light and the Circadian System

Moon and sun compasses in sandhoppers rely on two separate chronometric mechanisms

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