In Situ Foraging and Feeding Behaviour of Narcomedusae (Cnidaria: Hydrozoa)

Narcomedusae are a small and mostly oceanic group of hydromedusae whose tentacle morphology and comportment sets them off behaviourally and perhaps ecologically from most other medusae. Their tentacles are relatively few in number (2–40), stiff, and noncontractile, with points of insertion located w...

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Bibliographic Details
Published in:Journal of the Marine Biological Association of the United Kingdom
Main Authors: Larson, Ronald J., Mills, Claudia E., Harbison, G. Richard
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1989
Subjects:
Online Access:http://dx.doi.org/10.1017/s002531540003215x
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002531540003215X
Description
Summary:Narcomedusae are a small and mostly oceanic group of hydromedusae whose tentacle morphology and comportment sets them off behaviourally and perhaps ecologically from most other medusae. Their tentacles are relatively few in number (2–40), stiff, and noncontractile, with points of insertion located well above the bell margin. Eleven species representing eight narcomedusan genera ( Aegina, Aeginura , an undescribed aeginid, Cunina, Pegantha, Solmaris, Solmissus , and Solmundella ) were observed and collected in situ in the NW Atlantic, Arctic and Antarctic, using scuba and manned submersibles. In life, the tentacles of narcomedusae are nearly always held upwards over the bell or projected laterally. The major prey were other gelatinous zooplankton, especially salps and doliolids. In the laboratory, these relatively large prey were caught on the tentacles which bend inward and coil at the tips to bring food to the mouth. By extending the tentacles perpendicular to the swimming path, these medusae achieve a relatively large encounter area, thus increasing the probability of contact with prey, for the amount of protein invested in tentacles.