A study by the Central Marine Fisheries Research Institute (CMFRI) has reportedly documented the first evidence of both heterosexual and homosexual mating behaviour of the Indian squid, Uroteuthis duvaucelii.
The study, led by Geetha Sasikumar and K.K. Sajikumar of the Shell Fish Fisheries Division, examined squid samples collected from the Arabian Sea off Kochi. The analysis of 232 female squids revealed that 40% had sperm carrying structures (spermatangia) attached to their buccal membranes, a fleshy area right around their mouth. This indicated active mating throughout the year with peak activity recorded in October, according to a release. Researchers also found spermatangia implanted on the buccal membrane of a male squid, providing the reportedly first documented evidence of same-sex sexual behaviour of Indian squid.
Earlier in deep-sea squids
The findings were published in the Journal of Natural History. Earlier, same-sex mating behaviour had been documented only in deep-sea squids outside Indian waters, where scientists believed the dark environment may have contributed to such behaviour. Similar behaviour has also been observed in dolphins, it said.
The study also used statolith analysis to estimate the age of mated squids, finding that mating can begin as early as 98 days after hatching. Researchers found as many as 385 sperm packets attached around a single female squid’s mouth region, suggesting that females may mate multiple times with different males before laying eggs. According to researchers, this could be linked to dense spawning aggregations where random or opportunistic mating interactions may occur, leading to rapid growth of the squid species.
Conservation strategies
Researchers believe that understanding the mating system is essential to improve stock assessments and develop effective conservation and fisheries management strategies. They emphasised the need for further behavioural and physiological studies to fully understand the species’ reproductive dynamics, according to the communication.