Mating begins, in the accounts we have, when a male approaches and uses a modified arm, the hectocotylus, to court and then to transfer packets of sperm into the female’s mantle cavity. He may hold her in a way that covers her eyes. The insertion is repeated. It continues until the female has had enough, and in at least one species she may have to pull an overly persistent male off by force. This is not a delicate ballet that either animal can afford to stretch out. The lives are short, and the female’s one clutch is the whole stake.
The southern species, H. maculosa, has been studied closely enough to complicate the picture. Larger males mate more often. Females appear to prefer them, while males do not show a clear preference among females and do not seem to rely on odor to tell the sexes apart. Males mount other males regularly. Those male-male pairings tend to be shorter and to end without a packet being transferred, but the fact that they happen means the recognition is not perfect and may not be the point of the first grab.
Males also adjust the length of a mating to the female’s recent history. If she has not mated with another male, the copulation runs longer, and the male is less likely to be the one who breaks it off. Sperm competition, in other words, is visible in the clock. A female who will lay once is a resource with a deadline, and the behavior reads that way.
It is easy to make this sound rougher than a tide pool feels. Two small animals, a modified arm, a struggle that ends, and then months of a female alone with eggs. The rings, during all of this, are not the story. The story is a single season being spent.