Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-18T10:40:18.858Z Has data issue: false hasContentIssue false

Constant timing of medusa release in bivalve-inhabiting hydrozoans of the genus Eugymnanthea (Hydrozoa: Leptomedusae: Eirenidae)

Published online by Cambridge University Press:  22 July 2008

Shin Kubota*
Affiliation:
Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto University, Shirahama, Nishimuro, Wakayama 649-2211, Japan
*
Correspondence should be addressed to: Shin Kubota, Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto University, Shirahama, Nishimuro, Wakayama 649-2211Japan email: [email protected]

Abstract

At the end of the breeding season in autumn, under natural conditions, mature medusae of Eugymnanthea japonica are released from its host Mytilus galloprovincialis at night-time. In laboratory experiments, mature medusae of the congeneric species E. inquilina are also released at night-time in autumn. At that time of the year, sunset is earlier and the water temperature is lower than in summer, when, under natural conditions, medusa release of E. japonica takes place at sunset instead. The release thus takes place at the same hours of the day in summer as well as in autumn. The circadial timing of medusa release of E. japonica is likely constant throughout the whole period in the breeding season and not correlated with the decrease of light intensity at sunset.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Genzano, G.N. and Kubota, S. (2003) Synchronous mass release of mature medusae from the hydroid Halocordyle disticha (Cnidaria, Hydrozoa, Halocordylidae) and experimental induction of different timing by light changes. Publications of the Seto Marine Biological Laboratory 39, 221228.CrossRefGoogle Scholar
Govindarajan, A.F., Piraino, S., Gravili, C. and Kubota, S. (2005) Species identification of bivalve-inhabiting marine hydrozoans of the genus Eugymnanthea. Invertebrate Biology 124, 110.CrossRefGoogle Scholar
Kubota, S. (1989) Systematic study of a paedomorphic derivative hydrozoan Eugymnanthea (Thecata-Leptomedusae). Zoological Science 6, 147154.Google Scholar
Kubota, S. (1994) Reproductive season and some biological notes on a bivalve-inhabiting hydrozoan Eugymnanthea japonica (Thecata-Leptomedusae: Eirenidae) at Shirahama, Tanabe Bay, Japan, with comparison of related species. Publications of the Seto Marine Biological Laboratory 36, 277282.CrossRefGoogle Scholar
Kubota, S. (1996) Timing of medusa release in a hydroid Eugymnanthea japonica (Cnidaria, Leptomeduae, Eirenidae) commensal with a mussel. Scientia Marina 60, 8588.Google Scholar
Kubota, S. (1997) Two forms of bivalve-inhabiting hydrozoans that differ in timing of medusa release. In Den Hartog, J.C. (ed.) Proceedings of the 6th International conference on coelenterate biology. Leiden, The Netherlands: Nationaal Natuurhistorisch Museum, pp. 295299.Google Scholar
Kubota, S. (2000) Parallel, paedomorphic evolutionary processes of the bivalve-inhabiting hydrozoans (Leptomedusae, Eirenidae) deduced from the morphology, life cycle and biogeography, with special reference to taxonomic treatment of Eugymnanthea. Scientia Marina 64, Supplement 1, 241247.CrossRefGoogle Scholar
Kubota, S. (2004) Some new and reconfirmed biological observations in two species of Eugymnanthea (Hydrozoa, Leptomedusae, Eirenidae) associated with bivalves. Biogeography 6, 15.Google Scholar
Song, K. and Cho, L.C. (1998) Synchoronized release of medusae from three species of hydrozoan fire corals. Coral Reefs 17, 145154.CrossRefGoogle Scholar