appendages on a Calanoid copepod

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Franz Neidl
Posts: 747
Joined: Wed Jan 14, 2009 11:59 am
Location: Italy

appendages on a Calanoid copepod

Post by Franz Neidl »

Sometimes I see Calanoids with appendages on their antenna. I would be grateful if somebody knows the biological function of these appendages and the species name of the copepod.

First picture: Obj. 40x, DIC, stack with 7 pics
Second picture: Obj. 10x, DIC

Franz


Image


Image

BJ
Posts: 354
Joined: Sat Sep 29, 2007 10:53 am
Location: England

Post by BJ »

Hi Franz,

I think that this may be Calocalanus plumatus, but it is not a species that I have seen.

The consensus seems to be that role of these setae at the end of the antennae is sensing mechanical disturbances. Generally, chemo-sensory organs are concentrated at the base of the antenna, mechano-sensory at the tips and a mixture of the two along the length of the antenna.

The argument for mechano-sensory organs at the end of a long antenna is to isolate them from signals caused by movement of the copepod itself. The sensors then are to pick up movement of prey or predators. I would imagine myself that such a finely detailed structure would be to pick up precise information about small objects close at hand (ie nearby prey) - but I am not a physicist !!

Thank you for posting,

best wishes

Brian

Franz Neidl
Posts: 747
Joined: Wed Jan 14, 2009 11:59 am
Location: Italy

Post by Franz Neidl »

Hello Brian,

I thank you very much for your interesting answer. I am really impressed that this calanoid copepod has such a sophisticated kind of "sonar" detection !

Franz

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