Maternal care and juvenile feeding in a hyperiid amphipod (Oxycephalus clausi Bovallius, 1887) in association with gelatinous zooplankton

ABSTRACT

The manner of maternal care of the hyperiid amphipod, Oxycephalus clausi, was investigated at Senzaki, Nagato, Yamaguchi Prefecture, Japan. In situ observation underwater over a period of seven years as well as in vitro observation under laboratory conditions were conducted. Most of the amphipods (90.1%) were associated with gelatinous zooplankton. At least 13 species, including cnidarians, ctenophores, and salps hosted O. clausi amphipods. However, females presumably caring for demarsupiated juveniles were found only on the ctenophore Ocyropsis fusca, suggesting that O. clausi is selective in its choice of host species for reproduction. We also confirmed for the first time that O. clausi juveniles consume the surface tissue of the host ctenophore under laboratory conditions, indicating that they most likely prey on host tissue before leaving maternal care and then disperse from the host.

KEYWORDS:

• Gelatinous zooplankton
• Hyperiidea
• Ocyropsis
• ctenophore

Acknowledgements

The authors express our gratitude to Ms Miki Sasagawa and Ms Kumiko Maki for their assistance to the direct observations underwater. The authors thank Mr Hideki Abe, Mr Jun Adachi, Mr Yukihiro Akiyama, Mr Shinji Kitagawa, Mr Yuichi Saitou, Mr Chika Sasaki, and Mr Nobuaki Tsutaki for providing underwater photographs used for the analysis. Our special gratitude goes to a local diver, the late Ms Yuri Tanaka, who first discovered the reproduction of O. clausi at the study site for the first time and also provided underwater photographs for the analysis. The authors sincerely appreciate the editor and three anonymous reviewers who made constructive comments and suggestions to the earlier version of manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Kaori Wakabayashi http://orcid.org/0000-0002-1907-0653

Additional information

Funding

This work was partly supported by a grant from the Research Institute of Marine Invertebrates to K.W. [2017KO-27].