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Effects of light and gravity on circadian activity rhythms of the blue death‐feigning beetle
Author(s) -
HobanHiggins Tana M.,
Fuller Charles A.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1249
Subject(s) - circadian rhythm , photoperiodism , rhythm , period (music) , light intensity , biology , medicine , endocrinology , physics , botany , acoustics , optics
Throughout evolution, organisms have adapted to Earth's environment. The Circadian Timing System (CTS) allows an organism to anticipate and prepare for the cyclic daily changes resulting from the rotation of the Earth on its axis. In addition to these cyclic fluctuations, terrestrial organisms have also adapted to the constant presence of the Earth's gravitational environment. Exposure to altered lighting or ambient force environments affects circadian timing. This study was undertaken to characterize the circadian activity rhythms of a desert‐dwelling beetle, Cryptoglossa verrocusa, the Blue Death‐Feigning Beetle. Data were collected from individual beetles to allow determination of the effects of photoperiod, light intensity and ambient force environment on circadian activity rhythms in intact insects and in insects with reduced input through the leg proprioceptive gravity receptors (PGR). There was an effect photoperiod on the activity rhythm such that the length of the activity cycle increased as the length of the light cycle (i.e. photoperiod) decreased. Light intensity affected the period of the activity rhythm, with period increasing under higher intensity light. There was a similar effect of the ambient force environment. The period of the activity rhythm was longer in 2G than in 1G. These results indicate that both the lighting and gravitational environment influence the CTS and that the gravitational effects may be at least partially mediated by the leg PGR system. This work was supported by NASA grant NAG2‐1404 to TMH.