Rhythmic activity responses of the fiddler crabUca crenulatato artificial tides and artificial light

✍ Scribed by H. -W. Honegger

• Book ID: 104737383
• Publisher: Springer-Verlag
• Year: 1973
• Tongue: English
• Weight: 851 KB
• Volume: 21
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00355250

✦ Synopsis

The fiddler crab Uca crenulata, from California (USA), was exposed to artificial tides in order to differentiate between the influence of a tidal cycle from that of a light-dark cycle on its locomotor activity. Most crabs could be well synchronized by tides, but the activity patterns of other crabs was merely exogenously reinforced. Under constant conditions, after tidal treatment, crabs showed bimodal or unimodal activity patterns. When a 24 h light-dark cycle and a 12.35 h tidal cycle acted as concurrent stimuli, their effectiveness in synchronizing the crabs' activity was variable, depending on the individual. It is likely that crabs which tend to exhibit a unimodal activity pattern arc more sensitive to a light stimulus, whereas crabs with a bimodal activity pattern respond preferably to the tides. Thus, responses of endogenous activity of U. crenulata to tides and light-dark cycles are similar, suggesting that the basic oscillatory mechanism for circadian and tidal activity may be the same.