Help with IDing sex of O. bimaculoides

[sobhi]

Hi all!
I just got three O.bimacs two days ago for some behaviour experiments. They're in large, separate tanks. They were supposed to be all female, but I was just informed that one is male. How do I determine which one, without poking the animals too much and stressing them?? I know I should look for the hectocotylus and/or ligula, but it's hard to tell. I really need to know. Please let me know what you can think of. Thanks!

Sobhi
UT-Austin Marine Science Institute

 

[marinebio_guy]

Hi all!
I just got three O.bimacs two days ago for some behaviour experiments. They're in large, separate tanks. They were supposed to be all female, but I was just informed that one is male. How do I determine which one, without poking the animals too much and stressing them?? I know I should look for the hectocotylus and/or ligula, but it's hard to tell. I really need to know. Please let me know what you can think of. Thanks!

Sobhi
UT-Austin Marine Science Institute

The only way you can tells is by looking at the size of the suckers on I think the third arm on the right. On female the size of the sucker is more uniform while males there are suckers that are larger than the rest. It can take some practice to get it down. Look at pic's of bimac's on cephbase.utmb.edu, some of them are labeled male and female and point out the suckers.

 

[Neogonodactylus]

Sobhi,

How large are your animals. Juveniles can be tough.

A small, all glass aquarium really helps. Better yet, a round glass container so that you can always see the hectocotylus.

Roy