We all know the sad story of octopus sex, right? They live alone until it’s time to find a mate, they have sex a few times, then the males die. Females live a little longer to lay eggs, but die soon after they hatch. Turns out that the (still officially unnamed) Larger Pacific Striped Octopus breaks all the rules.
We now know this because cephalopod experts from UC Berkeley, the California Academy of Sciences and the Monterey Bay Aquarium spent two years observing their behaviour in captivity, confirming observations first made by Arcadio Rodaniche in the early 1980s. Their results appear in PLoS One today.
So what’s so different about the Larger Pacific Striped Octopus? Let me count the ways.
1. They mate beak-to-beak, with the female gripping the male (as above). This pattern is more like the sex in squid or cuttlefish. In other octopus species, the male wraps himself over the female, or remains at a distance, extending only his specialised sex arm to reach her mantle. The researchers speculate that beak-to-beak mating may let brooding females stay near their eggs while they mate again, or let males keep other males away from females they have mated with. (The more typical ‘distance mating’ means that multiple males can mate with a female octopus at the same time.)
2. Females mate and lay eggs over a much longer period of time than is typical for octopus: up to six months in their observations. This produced a brood that contained eggs at a variety of ages and stages of development. Females took care of the eggs until they all hatched, over a total period of eight months. This strategy may let the Larger Pacific Striped Octopus lay hundreds more eggs than other shallow-water octopus species, which become senescent when they first lay and die when that brood hatches.
3. Octopi are often solitary, but the female Larger Pacific Striped Octopus sometimes shared her den with the male she was mating with. The two would share food beak-to-beak and mate every day. Other reports have suggested that the species lives in larger groups.
Alas, although the Larger Pacific Striped Octopus has an extended spawning and brooding period, they still die once it’s done.
Image by Roy Caldwell UC Berkeley via Caldwell et al. 2015