Seasonal and Lunar Variation in the Emergence Time of a Population of Uca lactea annulipes (Milne-Edwards, 1837) at a Shore in Kuwait

Abstract

This study monitored the endogenous emergence time of the fiddler crab Uca lactea annulipes (Milne-Edwards, 1837) in the field, for the first time, at an intertidal shore in Kuwait, from 1997 to 2001. The results revealed a significant cyclic change in the median emergence time as the season progressed from winter, through spring and summer, to autumn (.44, 1.29, 3.12, and 1.1 h prior to the dead-low tide, respectively). The data also revealed a significant shift in the median emergence time according to moon phase (2.27 h at new moon versus 2.56 h at full moon prior to the dead-low tide). (Author correspondence: [email protected])

Keywords:

• Circadian rhythm
• Ecological significance
• Endogenous rhythm
• Fiddler crab
• Moon
• Nonphotic zeitgebers
• Ocypodedae
• Tidal rhythm

ACKNOWLEDGMENTS

This work was conducted in fulfillment of the requirements of the PhD Program at Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg im. Br., Germany.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.