Photos may not be reused without permission

Just in time for Valentine's Day 2012, Dr. Roy Caldwell shared some astonishing photos of two mating. Note that these images are very rare and the quality is high.Anmale perches on a rock keeping an eye out for a passing female. He displays his dark, enlarged suckers signaling that he is a male and flashes a characteristic brown stripe that says he is ready for action.A sharp-eyed female spots him and starts to approach. She knows what she wants and knows how to get it...The male moves in and reaches out to make contact. The female flashes a web display in response. This is going well!Here we see the smaller male engaging with the larger female. Roy observed the female's "passing cloud displays" during the process. Could such a display be a depiction of physical pleasure, like waves of excitement? Hmm, this is getting voyeuristic... Let's just observe in the name of science and not go too deep into their sexual psyche...In order to place a packet of sperm into the female, the male uses his modified third right arm called the hectocotylus. Here we see him feeling for the genital opening located inside her mantle cavity to insert the tip of the hectocotylus.OK, now it's definitely voyeuristic. Here we see the male leveraging his hectocotylized arm to insert its spermatophore into the female. From this angle, along the center of the inserting arm, you can see the "spermatophoral groove" which carries the spermatophore to its destination.In this photo, we see the contorted male in the process of transfering his spermatophore down to the left through the hectocotylized arm.Males can remain inserted into females for hours, repeatedly passing spermatophores down the hectocotylus. When the female moves, the male is often dragged along by his hectocotylus. This depicts his attempt to remain inserted and in effect, he's guarding his mate from other males. Mate-guarding has rarely been reported in octopus. Dr. Crissy Huffard has reported seeing it in the field; Roy was amazed to see it (and capture it on camera) in the lab.His job done, the male withdraws his hectocotylus from the female and jets away into the abyss.Quite interestingly, here we see the female ejecting a spermatophore from her funnel. (So much for romance.)Females, when ready to lay and brood their eggs, burrow into the reef flat and lay hundreds of garlands of eggs. She encompasses the eggs in her web. The gravel was removed from around this brooding female so that she can brood the pouch that she forms with her arms and web.The female broods her eggs for about a month. During this time she tends and aerates them, not moving from the burrow. She does not feed. About two weeks into development, we can see red eyespots forming. A week later, chromatophores in the skin of the larvae are visible.As the female broods her eggs, she begins to senesce living off of her energy stores. The wear and tear on her body is clearly seen in the loss of color and texture. Within days after the eggs hatch and the paralarvae swim up into the plankton, the female dies; her job is complete.So there you have it. Thanks again to Roy for sharing these amazing photos and providing descriptions of what we're seeing here. If you'd like to discuss this article with him and the rest of the TONMO staff and community, join us in this discussion thread