Contact with water functions as a Zeitgeber for the circatidal rhythm in the mangrove cricket Apteronemobius asahinai

摘要

The mangrove cricket Apteronemobius asahinai shows a circatidal rhythm in its locomotor activity, and this rhythm was shown to be entrained to artificial tidal cycles in the laboratory. To examine the Zeitgeber for this rhythm, in the present study, crickets were fixed with insect pins to prevent their body locomotion and a water stimulus was given to them by soaking in water, while recording their locomotor activities. A single water stimulus delayed the phase when given in the middle subjective low tide and advanced the phase when given in the later subjective low tide, whereas it had only a slight effect in the subjective high tide. We conclude that contact with water functions as a Zeitgeber for the circatidal rhythm.