TY - JOUR
T1 - Hatching of an estuarine crab, Sesarma haematocheir
T2 - Factors affecting the timing of hatching in detached embryos, and enhancement of hatching synchrony by the female
AU - Saigusa, Masayuki
PY - 2000/2
Y1 - 2000/2
N2 - The zoeas of the estuarine terrestrial crab Sesarma haematocheir hatch in synchrony with nocturnal high tides. Hatching is also highly synchronized among embryos: i.e., female-attached embryos would all hatch within 1 h, if the female is maintained at about 23°C. This study examined the factors affecting the timing of hatching in female-attached and detached embryos. The timing of hatching in the embryos detached from the female was somewhat affected by continuous light, salinity, and cluster size, but it was much more strongly affected by low temperature. In addition, a notable feature was that the influence of low temperature was markedly different between female-attached embryos and detached embryos. Hatching of this crab occurs after a special developmental process for hatching ('hatching program') that requires 48-49.5 h. This program would be mediated by a temperature-dependent process. Hatching of this crab cannot be fully explained in terms of osmotic effects. Since hatching of female-attached embryos was highly synchronized, the female should release an (unknown) stimulus enhancing hatching synchrony among embryos. Highly synchronized hatching among embryos would enable the female to release hatched zoeas into the water all at one time.
AB - The zoeas of the estuarine terrestrial crab Sesarma haematocheir hatch in synchrony with nocturnal high tides. Hatching is also highly synchronized among embryos: i.e., female-attached embryos would all hatch within 1 h, if the female is maintained at about 23°C. This study examined the factors affecting the timing of hatching in female-attached and detached embryos. The timing of hatching in the embryos detached from the female was somewhat affected by continuous light, salinity, and cluster size, but it was much more strongly affected by low temperature. In addition, a notable feature was that the influence of low temperature was markedly different between female-attached embryos and detached embryos. Hatching of this crab occurs after a special developmental process for hatching ('hatching program') that requires 48-49.5 h. This program would be mediated by a temperature-dependent process. Hatching of this crab cannot be fully explained in terms of osmotic effects. Since hatching of female-attached embryos was highly synchronized, the female should release an (unknown) stimulus enhancing hatching synchrony among embryos. Highly synchronized hatching among embryos would enable the female to release hatched zoeas into the water all at one time.
KW - Embryos
KW - Endogenous clock
KW - Environmental factors
KW - Estuarine crab
KW - Hatching
KW - Synchrony
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U2 - 10.1023/A:1011118726283
DO - 10.1023/A:1011118726283
M3 - Article
AN - SCOPUS:0034006862
VL - 56
SP - 93
EP - 102
JO - Journal of Oceanography
JF - Journal of Oceanography
SN - 0916-8370
IS - 1
ER -