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A PERSISTENT DIURNAL RHYTHM IN CHAOBORUS LARVAE. I. THE NATURE OF THE RHYTHMICITY 1
Author(s) -
LaRow Edward J.
Publication year - 1968
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1968.13.2.0250
Subject(s) - zeitgeber , rhythm , entrainment (biomusicology) , darkness , circadian rhythm , larva , atmospheric sciences , biology , environmental science , ecology , physics , botany , circadian clock , endocrinology , acoustics
Larvae of Chaoborus punctipennis Say (Diptera: Culicidae) were maintained under constant conditions in two 152‐ × 10‐cm columns containing lake water and sediments. Visual counts of the larvae in the columns were made hourly with a flashlight equipped with a red filter and darkened reflector. Activity was observed during dark periods; however, no activity was observed during light periods. A diurnal rhythm of activity persisted up to 10 days in constant darkness. The phase of the rhythm was reset by entrainment under differing light regimes, as well as by temperatures of 5C or less. These critical low temperatures also abolished activity. The offset of light was demonstrated to be the Zeitgeber for this rhythm; therefore it is necessary that under natural conditions these larvae receive some offset stimulus from the setting sun.