Monday, February 05, 2007

Sex n the Nudi

It all began when Marcus showed me the photo of a nudibranch he took at Pulau Hantu.

Was pretty sure it's a Gymnodoris rubropapulosa as it has bigger dots and doesn't have the orange line usually found at the edge of an alba's head.

Anyway, this is how a Gymnodoris rubropapulosa looks like. Photo taken on Semakau Landfill just last month.

Gymnodoris rubropapulosa nudibranch

But before I digress too much, so what's so interesting about its sex life?

Warning: Things may get a bit R(A) below.

Can you imagine having sex at the cost of your life?

Or can you imagine having sex and also a meal (i.e. 2 in one) at the same time?

There is a Chinese saying - 饱暖思淫, which means when one has eaten and feels warm, he will think about sex. But guess this doesn't really apply to Gymnodoris.

For many of them, sex = food

Nudibranchs are hermaphrodites. Each slug has both male and female reproductive organs.

When they mate, they get into a 69 position. Sometimes they fertilise each other, at other times one may take on a male role while the other, a female.

But what's different about gymnodoris nudibranchs is that they feed on other slugs, and sometimes, that include nudibranchs of the same species.

So you can imagine when one gymnodoris saw another gymnodoris of the same species, it would mean both dinner and sex!

Bascially, they will get connected in the 69 position, and at the same time, try to move on to have a bite of the other party, and thus they will be going in circles, where the point of contact between their reproductive organs will be the centre of the circle.

It's like those old Chinese kungfu movies, where two kungfu masters walk around in circles try to find loopholes in the other party's defense and launch an attack.

Eventually, the faster one will catch hold of the other party, and starts swallowing it. Usually, the last bit of prey left exposed is the reproductive organ. Not sure if it will eventually gets eaten as well, though I do wonder if the gymnodoris's head is so flexible that it can bite onto something just next to its "waist".

And sometimes, I also wonder, if the gymnodoris is so flexible, will it actually bite onto its tail one of these days, thinking that its another prey? It's like.. "Hmmm! Yum Yum! OUCH! Shucks! I bite myself again!"

Do such things happen, I wonder? I mean, I've seen dogs chasing after their tails. Can this happen to nudibranchs as well?

But anyway, the joke of the day is when I was trying to describe things to Marcus and November, I got a bit excited and being the non-bio person, instead of saying "reproductive organs", I just said the first sexual organ term that came to my mind, "testicles".

Getting a bit crude here, but imagine, the whole slug kenna eaten except for its balls??!!??!!


In the first place, slug having balls already sounded really funny. But then again, we already have fish balls, crab balls, prawn balls, sotong balls... And mind you, sotong (aka squid) is also a mollusk like nudibranchs, maybe one day they will hv slug balls or nudi balls too???!!!???


Anyway, found out from the Net later that nudibranchs do have testes! Probably not quite like the "balls" mammals have though. Maybe something like beads or ball bearings??!!???


And the funniest of all, it din occur to me that I've said the wrong things until we had the discussion again at the prata place! And we had quite an audience sitting at the nearby tables, listening to our rather loud discussion on nudibranch sex.

Anyway, last Sunday's trip to Pulau Hantu is a good one. Haven't been there for at least half a year.

But sadly, the sedimentation in the lagoon was really getting quite bad - the water used to all the way go up to my knee, but now, only slightly higher than my ankle most of the time, even though the tide was actually not as low as the past few times we were there.

I didn't see any razor fish in the lagoon. Was thinking with the shallow water, skali they may actually kenna stuck heads down with their tails pointing skywards :P

Just kidding here, but I really hope they managed to get to some deeper pool when the tide went down.

Saw a number of the usual suspects, e.g. the Merten's carpet anemone (Stichodactyla mertensii), the Magnificent sea anemone (Heteractis magnifica), seagrasss, seaweeds, swimming crabs, stone crabs, red egg crabs etc, but din see any nemos, though I'm quite sure they were hiding in some of the anemones I saw, since I could feel quick knocks on my metal chopsticks when I was touching the anemones with them.

Some of the other wild things I saw at Hantu which I captured on photo include:

Giant clam, Tridacna crocea

One of the giant clam species. This one was not really a giant though, maybe about 10-15 cm.

Soft corals

Flowery soft corals...


Zoanthids, aka colonial anemones, look at the ones under water and you can see the opened polyps...

Galaxy hard coral, Galaxea sp.
A half-bleached galaxy hard coral... Dunno what happened to it...

Sand-sifting sea star, Archaster typicus
And on my way back, a common seastar. Not sure why, but the common seastars here seem to be smaller than the ones at Chek Jawa and Semakau Landfill. Is it because there is less food here, or are they a smaller sub-species??? Seems to have more common seastars at the other smaller lagoon though, or at least, they are easier to find. Is it because there is more food there?

Anyway, was glad to see that apart from the sedimentation, most things were still doing quite well. Hopefully the next time I go to Pulau Hantu, things will stay the same, if not better!

Read also:
1. Marcus' take on the sotong ball and his account of the trip.
2. More info on the mating behaviour of Gymnodoris nudibranchs at the Sea Slugs Forum.


Anonymous said...

Those things are amazing.

juanicths said...

yo~~~ interesting stuff on nudi sex ^^

~mantamola~ said...

mm...interesting. didn't know there r nudis having same habit with mantis except never heard of any bi, i means hermaphordite mantis

shenjiaqing said...

Hey, this is very 'educational'! Since when do you started to put efforts to study or get to know about this sex life? :P
Thanks for sharing your 'knowledge' , ya, and the jokes too.

Ron Yeo said...

Eh... Not that I put in additional effort lah. I've always been interested in slugs mah...