THE LIGHT-DARK CYCLE AND A NONLINEAR ANALYSIS OF LUNAR PERTURBATIONS AND BAROMETRIC PRESSURE ASSOCIATED WITH THE ANNUAL LOCOMOTOR ACTIVITY OF THE FROG, RANA PIPIENS

¹ Department of Anatomy, State University of New York, Upstate Medical Center, Syracuse, New York 13210

The spontaneous locomotor activity (LA) of adult male frogs (Rana pipiens, Northern variety) was monitored throughout the year in an apparatus which detected vertical water movements. Frogs exposed to the seasonal change in ambient light and maintained at a constant mean annual temperature of 19.3 ± 3.1 ° C exhibited significant correlations of activity to the light-dark cycle, barometric pressure and lunar perturbations. When the light : dark ratio was < 1.0 (October to March) frogs displayed "random" activity throughout the 24 hr period ; but with the L:D ratio between I .0-1.45 activity was primarily nocturnal between 2100-0000 hr and at sunrise, while with a L:D Ratio > 1.45 maximal activity occurred at sunrise. Activity also was correlated with time of lunar high transit (HT) where occurrence of HT during daylight hours in April to June was associated with depressed activity, while HT during daylight in October to March was coincident with elevated period of activity. Use of a FORTRAN IV Program to analyze time of maximal LA each day throughout the year revealed oscillatory behavior patterns with periods similar to lunar tidal cycles. An alpha-series of cycles (55, 105, and 162 day periods) were significantly associated and dominant on days of high barometric pressure (above the annual mean of 761 mm Hg) and characterized by high levels of activity (above the annual mean of 313 events/day). A beta-series (30, 60, 90 day cycles) was dominant on days of low barometric pressure (< 761 mm Hg) and coincident with low levels of activity (<313 events/ day). Spontaneous activity of frogs apparently is not random, but reflects an association with basic geophysical forces which elicit a complex but definable behavior pattern.