Diel timing of
molting and metamorphosis of Panulirus japonicus phyllosoma larvae
under laboratory conditions
H. Matsuda, T. Takenouchi, T.
Yamakawa-2003
Fisheries
Science, 69(1):
124
Abstract:
The timing of molting and metamorphosis
was monitored for Panulirus japonicus phyllosoma larvae cultured in
the laboratory. Larvae cultured under natural light-dark cycle molted
synchronously within approximately 1.0 h before and after sunrise,
except for a short period after hatching; the timing of molting changed with
time of sunrise. When three artificial light-dark cycles were introduced,
larvae molted around the start of lighting, irrespective of the light-dark
cycles. In the event of a sudden change in the start or end of lighting,
molting was regulated by an endogenous rhythm. The start of lighting had a
greater impact on the timing of molting than the end of lighting, suggesting
that sunrise is probably the critical signal for phase-setting in molting
rhythm. Metamorphosis to the puerulus stage occurred within 0.4 h
before and 1.2 h after sunset under a natural light-dark cycle, and the
timing of metamorphosis was also changed artificially by regulating the end
of lighting.
(Fisheries Research Division, Mie Prefectural Science
and Technology Promotion Center, Shima, Mie 517-0404, Japan, Tel:
81-599-53-0130. Fax: 81-599-53-2225. Email:
matsuh07@pref.mie.jp)