Circadian Locomotor Activity in  The Freshwater Crab, Barytelphusa  Cunicularis (Westwood, 1836): Under  Artificial Illumination

Shipra Sinha

Volume : II, Issue : II, February - 2013

Circadian Locomotor Activity in The Freshwater Crab, Barytelphusa Cunicularis (Westwood, 1836): Under Artificial Illumination

Shipra Sinha

Abstract :

In the present study, it was examined if the locomotor activity of both male and female Indian freshwater crab, Barytelphusa cunicularis is rhythmic under LD 12:12 photo cycles and if this rhythm free runs following their transfer from LD to DD or LL. Further, it was investigated if B. cunicularis exhibits bimodal pattern of locomotor activity under LD, DD and LL schedules. The specimens were placed for recording the activity at each light regime in between 10-12 days for male crabs and 15 days for female crabs. The locomotor activity was recorded at three different light regimes; DD, LD (12:12h) and LL at 150 lux. Data were analyzed for documenting a circadian rhythm in locomotor-activity (? = 24h) with the help of Cosinor rhythmometry. The locomotor activity rhythm in B. cunicularis, when exposed to LD the crab shows the bimodal and multimodal patterns of activity anticipating lights-on and lights-off condition. The free running rhythm under constant light and dark regimen are observed irrespective of gender. The 24-h average mean is more in male as compare to female. Amplitude is higher in DD and lower in LL conditions. It may be possible that, the crab possesses a functional oscillator, which regulates its overt circadian rhythm in locomotor activity.