Creating Pacific Octopuses
reproduction is the ultimate purpose in life. Once this task is completed, it will die.
Before a courtship can begin between two octopuses, they first need to find each other. It is believed that a male will sense chemical attractants produced by a female and then search for her.
During courtship both octopuses use their sense of sight to determine attraction. Males are looking for a large female. Larger diploid females produce more haploid eggs, by meiosis If more eggs are fertilized, it gives the male a greater probability to pass on his genes. Similarly, females are looking for a male with a large ligula. The ligula is a portion of the male’s hectocotylus and is located at the end of his arm. It contains erectile tissue and will become larger with attraction. To turn the lady on, the male will flash intricate skin displays with his chromatophores. He will use her response to judge her willingness and readiness to mate. Both males and females may have more than one mate.
Sexual interactions occur between the Pacific octopuses in two positions: side by side or with the male on top. The male then ejects a haploid spermatophore, which was created by meiosis, from his ligula and transfers it into his hectocotylus’s groove. Shockingly, the Pacific octopus's spermatophores are about three feet long and contain up to seven billion sperm! The spermatophore then proceeds to travel down the ciliated groove of his hectocotylus, while the male places his arm into the female’s mantle. He places the spermatophore into the female’s oviduct with his ligula. It is unknown how the male is able to find her oviduct, but it is believed she secretes chemicals to help him in this process. The male’s ligula is also believed to be able to remove previous males’ spermatophores from within the female. During this sexual encounter, the male’s heart skips a beat and the female’s respiration rate increases. The Pacific octopus takes about an hour to pass a single spermatophore and the entire mating process, not including courtship, takes about three to four hours, on average.
The female stores the sperm within her their body, until she is ready to lay the eggs. When eggs travel out of the female's body, they travel past the contained sperm and become fertilized. About 20,000 to 100,000 eggs, each the size of a grain of rice, will be laid. She places these eggs along the wall of a chosen den. It will take her a couple of days to lay all of them. The peak time of year for egg-laying, or spawning, is from April-May near Alaska and from May-July near Japan. It takes about 150-230 days, about 6 or 7 months, for the eggs to hatch. She will rarely leave the eggs during the entire incubation period. During this time, the female will touch the eggs with her arms and aerate them with her siphon. She does this to keep them clean and free of fungi, bacteria and algae. After they hatch, she will blow them out of the den and into the open ocean. (This can be viewed in the video above. I recommend watching at minute three.)
Upon hatching, the offspring immediately swim to the ocean's surface. They will then experience a planktonic stage for about 30-90 days. Many of the octopuses die during this stage of life. More information about this can be found here.
The final stage of both the mating process and the octopus’s life cycle is senescence. Both male and female Pacific octopuses experience this dementia-like state of being. Males will experience this alone, very soon after mating. Females, on the other hand, will lay eggs and faithfully tend to them while going through senescence.
During senescence, the octopuses refuse to eat and will lose a lot of weight. The octopuses' bodies will begin to metabolize muscle because they do not store body fat. One can lose up to 50% of its body weight. Also, males tend to move around in the open water without a purpose. They do not hunt or forage, and rarely return to their dens. This makes them easy prey. The last sign of senescence is the appearance of white lesions on the skin. These lesions will not heal because all of the octopus’s healing processes cease during senescence. Infections are often a deadly side effect.
The octopus experiences senescence until death, which usually arises from starvation or predation. The females die almost immediately after the young hatch.