Southern Dumpling Squid Exhaust Themselves With 3 Hour Mating Sessions
Posted on July 18, 2012
Researchers from the University of Melbourne have discovered that southern dumpling squid exhaust themselves with their three hour mating sessions. The squid engage in these impressively long mating sessions despite the cost - less energy to forage for food or fight off predators. The research team studied dumpling squid (Euprymna tasmanica) that live in waters of Southern Australia including Port Phillip Bay and Tasmania and reach about 7cm long at adult size.
The scientists say dumpling squid engage in up to three hours of mating and males appear to initiate mating whenever the opportunity arises. The male grabs the female from underneath, and holds her in place throughout copulation. Both males and females can change color from a sandy yellow to dark purple with green and orange highlights. They can also produce a cloud of ink as a decoy to help them escape from predators.
The researchers collected dumpling squid from St Leonards in south-eastern Australia and tested their swimming endurance against a constant current of water in the lab. The squid were then allowed to mate and their swimming ability re-tested. The researchers found that it took both the male and female dumpling squid up to thirty minutes to recover after the exhausting mating sessions.
University of Melbourne Master of Science student Amanda Franklin says, "We found that after mating, both male and female dumpling squid took up to thirty minutes to recover to their previous swimming ability. This suggested that the squid were suffering from temporary muscle fatigue. Our results were a little surprising as the degree of fatigue was similar in both genders even though mating looks more strenuous for males. We predict that during this phase of muscle fatigue, squid may hide in the sand to avoid predators until they have recovered. The cost to them in doing this of course is that they cannot forage for food or search for other mates at this time."
The research was published here in the journal Biology Letters.