Journal of comparative physiology

, Volume 107, Issue 1, pp 13–37 | Cite as

Plasticity in an isopod's clockworks: Shaking shapes form and affects phase and frequency

  • J. T. Enright
Article

Summary

The stimuli which normally synchronize the endogenous tidal rhythm of the isopodExcirolana chiltoni arise from turbulent waves moving across the beach. A phase-response curve for two-h pulses of similar stimuli has been derived from experiments in which individual isopods were treated with vigorous intermittent shaking in a flask of seawater. This response curve differs qualitatively from all results previously obtained by administering pulse stimuli to ordinary circadian rhythms: it is bimodal per circadian cycle, with two intervals of about 6 h duration, during which phase advance of up to 4 h results from treatment, separated by two other 6 h intervals during which phase delay of up to 3 h is evoked. This kind of responsiveness to entraining stimuli is of clear adaptive value for synchronization of a circadian rhythm to the mixed semi-diurnal tidal regime of the isopods' habitat.

In addition to inducing phase shifts, this same treatment can strongly modify the persistent pattern of activity, and such effects also depend upon phase of treatment: when administered shortly before or shortly after onset of activity, shaking tends to increase the amount of activity in subsequent cycles; when administered in antiphase (6 to 18 h after activity onset), it tends to decrease the activity in the dominant activity peak, and to transform a unimodal pattern of activity into a bimodal pattern. Such induction of a persistent secondary peak of activity in a previously unimodal circadian pattern demonstrates a plasticity which has not been previously reported in those circadian rhythms which are synchronized to the day-night cycle.

Keywords

Beach Circadian Rhythm Phase Advance Activity Onset Similar Stimulus 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Barnwell, F. H.: The role of rhythmic systems in the adaptations of fiddler crabs to the intertidal zone. Amer. Zool.8, 569–583 (1968)Google Scholar
  2. Bennett, M. F., Shriner, J., Brown, R.A.: Persistent tidal cycles of spontaneous motor activity in the fiddler crab,Uca pugnax. Biol. Bull.112, 267–275 (1957)Google Scholar
  3. Bünning, E., Müller, D.: Wie messen Organismen lunare Zyklen? Z. Naturforsch.16b, 391–395 (1961)Google Scholar
  4. DeCoursey, P. J.: Daily rhythm of light sensitivity in a rodent. Science131, 33–35 (1960)Google Scholar
  5. DeCoursey, P. J.: Function of a light response rhythm in hamsters. J. cell. comp. Physiol.63, 189–196 (1964)Google Scholar
  6. Enright, J. T.: The tidal rhythm of activity of a sand-beach amphipod. Z. vergl. Physiol.46, 276–313 (1963)Google Scholar
  7. Enright, J. T.: Entrainment of a tidal rhythm. Science147, 864–867 (1965a)Google Scholar
  8. Enright, J. T.: Synchronization and ranges of entrainment. In: Circadian clocks, ed. J. Aschoff, pp. 112–124. Amsterdam: North Holland 1965bGoogle Scholar
  9. Enright, J. T.: A virtuoso isopod: circa-Iunar rhythms and their tidal fine structure. J. comp. Physiol.77, 141–162 (1972)Google Scholar
  10. Enright, J. T.: Resetting a tidal clock: a phase-response curve forExcirolana. In: Biological rhythms in the marine environment (ed. P. DeCoursey, pp. 103–116. Columbia, S.C.: Univ. South Carolina Press 1976Google Scholar
  11. Enright, J. T.: The circadian tape recorder and its entrainment. In: Physiological adaptation to the environment (ed. J. Vernberg), pp. 465–476. New York: Intext Educational Publ., 1975Google Scholar
  12. Eskin, A.: Some properties of the system controlling the circadian activity rhythms of sparrows. In: Biochronometry (ed. M. Menaker), pp. 55–80. Washington, D. C.: Nat. Acad. Sci. 1971Google Scholar
  13. Heusner, A., Enright, J. T.: Long-term activity recording in small aquatic animals. Science154, 532–533 (1966)Google Scholar
  14. Klapow, L. A.: Natural and artificial rephasing of a tidal rhythm. J. comp. Physiol.79, 233–258 (1972a)Google Scholar
  15. Klapow, L. A.: Fortnightly molting and reproductive cycles in the sand-beach isopod,Excirolana chiltoni. Biol. Bull.143, 568–591 (1972b)Google Scholar
  16. Naylor, E.: Tidal and diurnal rhythms of locomotor activity inCarcinus maenas (L.) J. exp. Biol.35, 602–610 (1958)Google Scholar
  17. Pavlidis, T.: Mathematical models of circadian rhythms: their usefulness and their limitations. In: Biochronometry (ed. M. Menaker), pp. 110–116. Washington, D. C.: Nat. Acad. Sci., 1971Google Scholar
  18. Pittendrigh, C. S.: Circadian rhythms and the circadian organization of living systems. Cold Spr. Harb. Symp. quant. Biol.25, 159–182 (1960)Google Scholar
  19. Pittendrigh, C. S.: Circadian systems. I. The driving oscillation and its assay inDrosophila pseudoobscura. Proc. nat. Acad. Sci. (Wash.)58, 1762–1767 (1967)Google Scholar
  20. Pittendrigh, C. S., Bruce, V., Kaus, P.: On the significance of transients in daily rhythms. Proc. nat. Acad. Sci. (Wash.)44, 965–973 (1958)Google Scholar
  21. Renner, M.: The contribution of the honey bee to the study of time-sense and astronomical orientation. Cold Spr. Harb. Symp. quant. Biol.25, 361–367 (1960)Google Scholar

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • J. T. Enright
    • 1
  1. 1.Scripps Institution of OceanographyUniversity of CaliforniaLa JollaUSA

Personalised recommendations