イセエビの日周行動のパターンとその乱れ

概要

論文の詳細を見る
Japanese spiny lobster (Panulirus japonicus) is a nocturnal animal. We observed the diurnal variation of the spiny lobster activity in an experimental tank under a diel L/D cycle of 12:12. Under a standard condition with 3.3×10^2 lx daytime brightness and 0 lx nighttime brightness, the spiny lobsters exhibit clear diurnal variation pattern almost in phase with the brightness change. The pattern, however, is changed or collapsed under several conditions as follows: (1) When the nighttime brightness was higher than a threshold value of about 1.8×10^<-4> lx, the nighttime activity is considerably suppressed. (2) Under continuous darkness, the phase of the diurnal variaton pattern is shifted and its period becomes 23 hours rather than 24 hours. By using this nature, the minimum recognizable daylight brightness to the spiny lobsters was estimated to be about 2.3×10^<-5> lx. (3) When a spiny lobster was put in a new circumstance, the activity of the spiny lobster is generally increased considerably for the first several days. This type of activity increase occurs both for the nighttime and in daytime in parallel. (4) A collapse of the activity pattern would occur not only due to external conditions but also due to internal conditions of the spiny lobsters. The nature of the spiny lobster activity at the time of molting is discussed as an example.
日本海洋学会の論文
1996-08-30