Saturday, March 31, 2012

Octopus Reproduction

Heather Ylitalo-Ward, a PhD candidate at University of Hawaii Manoa, shared with us a fascinating glimpse into the world of cephalopod reproduction.
Here are a few of the interesting things she shared:

1. "OCTOPI" is incorrect. The plural form of octopus is OCTOPUSES.

2. In HI waters, there exist 19 known species of octopus.

The few that are described here are common in Hawaiian waters...

3. The Bobtail Squi

d has a symbiotic relationship with the bacterium Vibrio fischeri which makes them glow. This helps them to hide from predators. When they swim at night, near the surface, they glow like the moonlight. Predators swimming below them then cannot see them. This helps to protect them.

4. The Day Octopus can lay up to 700,000 eggs. Their color and texture can change to help them camouflage themselves. Their cells contain

chromatophore pigments, and they can control each cell's color


5. Night Octopus

These are pinkish in color with rows of white dots down their tentacles.
They live in shallow waters and legs can reach 2 m long.

6. Rock Tako

These live in tidepools.
At night, they emerge from the water and hunt for crabs.

The head is 8 cm; legs reach 12 cm.

7. Paper Nautilus

These are actually a form of octopus. The females create a "paper" like shell around themselves for protection, but they can remove the shell.
They live in open oceans. They live near the surfaces.
The males have no shell.
They ride on jellyfishes.
Extreme sexual dimorphism: females are 100mm long; males 20 mm long.

8. Blanket Octopus

Live in open oceans.
When young, they carry tentacles of man-of-war around themselves to protect themselves from predators.

9. Big Fin Reef Squid

These are prevalent in shallow waters.
Males and females are equal in size, about 33 cm at full length.
These are the "calamari" that people eat.
They mate rapidly.


The male has one arm that is larger than the others - the "hectocotylus."
In reproduction, the male attempts to place the end of this arm into the female's vaginal pocket.
He then delivers "sperm packets" (as many as possible, one by one) into the female.
For the first packet, he reaches his arm into himself and selects the packet. He then places it into the female.
Subsequent packets slide down the arm into the female.

She stores them. She can store packets from multiple males in different pockets.
She can choose (seen once) to select and remove particular packets.

Cuttlefish mate mouth to mouth.
She has a pocket in her mouth for storing the sperm.
The male first sprays her mouth with water to remove other males' sperm, and then deposits his own.

The paper nautilus and certain other species actually have an arm that detaches from his body and swims on its own over to the female to deposit the sperm. He dies when his arm detaches, and he hopes that the arm reaches the female.

The Blanket Octopus also has an arm that detaches and crawls into the female.

The Reef Squid also mates mouth to mouth or side by side. They lay egg cases.

Here is a National Geographic clip of octopus reproduction:

1 comment:

  1. Heather! these octopuses are just like humans except all the arms!


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