Imagine the idea of remaining celibate your entire existence right until the last day of your life where you engage in a massive orgy of sorts. Intrigueing? The carribean reef squid(Sepioteuthis sepioidea)does just that! A torpedo-shaped squid that averages in length at about 20cm, belongs to the Cephalopod family and can be found in the shallow reefs of the carribean sea in schools of 4-30. If you think this is going to be just another boring entry extolling the biological traits of this cephalopod– think again! One of the most interesting aspects about this squid is that, like other cephalopods, its is semelparous. Semelparous organisms reproduce only once in their lifetime, thus explaining the title of this entry you are reading. The crux of this entry, will thus focus on the mating ritual of the carribean reef squid.For the most part of their lifespan, the Sepioteuthis sepioidea are perfectly content having no sex at all, swimming around in schools in the day and hunting alone for food at night, consuming up to 60% of their body mass with their voracious appetites. However, this all changes as they approach the last weeks of their lifespan, and their voracious appetite for food translates into an overwhelming sex drive. During mating season, these squids are known to mate for hours at a time, and their mating ritual precedes a courtship process, which can be a very interesting sight indeed. During the courtship ritual the Sepioteuthis sepioidea change their colouration, shape and texture via nervous control of their chromatophores. Males do this to enhance their attractiveness to the opposite sex whereas females do so to indicate their interest.
In the first stage of the mating game, a male will compete with about 4 other squids. Upon emerging victorious, it would then approach a female. One interesting effect about these male squids to note is that unlike our human counterparts, these reef squids are actually attracted to females of larger proportions! They will however, eventually settle with a same-sized female. The game begins when the male “flashes” and pulsates, gently sticking its tentacles onto her skin just below the eyes. A willing female often turns pale and the pair swim fairly quickly side-by-side in a rocking motion. Then he darts around in front of her and sticks the spermatophores in place. Females play games too! A female squid might play “hard to get” by putting an agonistic pattern of rough vertical zebra stripes on her skin and swimming away quickly. More often than not, this is being done to assess the male squid’s agility in “chasing” her. In the meantime, other male contenders might intercept by displaying neat zebra stripes across their mantle. If the male proves worthy, he will then be allowed to inseminate a sticky cluster of sperm into her, displaying a pulsating pattern, like a victory routine.
All good things must come to an end however, and this vibrant display of courtship and vigour has to eventually end too. The impregnated female squid searches for little protected cracks and crevices in the reefs. She squeezes her way in and moves eggs out past the spermatophoric gland to fertilize them, gives them a gel coat and attach them in small clusters. The female turns into a dark brown shade whilst doing so. Shortly after, the female dies. The male squid also dies, becoming frail and susceptible to predator fish, such as tuna and yellowtail. Nevertheless, this intricate display of colour and marine art is indeed a sight to behold. If you happen to be snorkeling around shallow Caribbean waters in the morning, do look out for the Caribbean reef squid. If you are lucky enough you’d be able to witness first-hand this wondrous spectacle of Mother Nature!
If you wish to view videos of the Sepioteuthis sepioidea, please click on the following link :
Done by: Melissa Lim Ying Pei, U098708N
Science Direct- Encyclopedia of Ocean Sciences: Cephalods