We have been witness to some very interesting reproductive behavior amongst Cephalopods when diving in Lembeh this week. Both Cuttlefish and Reef Squid have all been putting on quite the show! These two beautiful Crinoid Cuttlefish (distinguished by the spotted pattern on their lower arms) were caught mating beneath the overhangs of a colorful sponge, and were so caught up in the activity at hand that they didn’t seem to notice the gathering crowd of divers.
When a female Cuttlefish is ready to mate, males in the area begin to compete for her affection by partaking in colorful, non-violent threat displays. The winning male (i.e. most masterful with his color flashes) proceeds to “kiss” the sought-after female, grasping her face tightly to his and depositing a sperm-filled sac into a specialized pouch near her mouth. Most females end up “kissing” multiple males before laying her eggs, which allows her to choose from a variety of spermatophores when she begins the fertilization process.
Another amazing show was put on by a large group of Bigfin Reef Squid this week. A group of divers watched for 20 minutes while this group of thirty Squid appeared to mate and lay their eggs. Couples swam together in a side-by-side fashion, allowing the males to deposit his spermatophore in a well-placed position. When the females went directly to the reef to lay their eggs, the eggs pushed past the deposited spermatophore, directly fertilizing the freshly laid eggs. Whether or not this style of group mating is common, it is definitely not a sight that is commonly encountered by divers! After only 2 weeks in these warm Indonesian waters, all the juvenile squid will be preparing to pop out of their egg-casings. Wouldn’t that be another amazing sight to see!