(Press-News.org) In order to pass on their genes, southern dumpling squid engage in up to three hours of mating with each partner, but University of Melbourne researchers have found that this results in a reduced ability to swim for up to 30 minutes afterwards.
The research provides new insight into the evolution of reproductive strategies and behaviours and is the first time that the energetic costs of mating have been shown to affect physical abilities after mating.
The research was conducted by Master of Science student Ms Amanda Franklin with Ms Zoe Squires and Dr Devi Stuart-Fox from the Department of Zoology at the University of Melbourne, and is published today [Wednesday 18 July] in the international journal Biology Letters.
The 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.
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 colour 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.
Ms Franklin said the team was keen to understand the impact of such an extensive mating ritual because although traditionally thought to be trivial, the energetic costs of mating could reduce an animal's survival if it decreased the ability to avoid predators and forage for food.
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.
"We found that after mating, both male and female dumpling squid took up to thirty minutes to recover to their previous swimming ability," Ms Franklin said.
"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."
Dumpling squid are closely related to about 10 bobtail squid species found around the world, including the waters around Hawaii and the South China Sea. These species have similar mating habits to the southern dumpling squid.
"Dumpling squid live for less than a year, and may engage in the energetic activity of mating many times within their short breeding period. This reproductive strategy may have other costs to individuals besides energy loss and we have investigated this further by assessing the effect of mating on female lifespan. We're hoping to report the results of this experiment very soon."
INFORMATION:
For more information:
Images of dumpling squid are available.
Ms Amanda Franklin, Department of Zoology, University of Melbourne, M: 0439395679, E: a.franklin@student.unimelb.edu.au
Dr Devi Stuart Fox, Dept. Zoology, University of Melbourne, M: 0412 726 340, E: d.stuart-fox@unimelb.edu.au ;
Nerissa Hannink (Media Office), P: +613 8344 8151, M: +61 430 588 055, E: nhannink@unimelb.edu.au
Promiscuous squid fatigued after mating
2012-07-19
ELSE PRESS RELEASES FROM THIS DATE:
Leading scientists call for improved innovation policy across Europe
2012-07-19
New report from the European Science Foundation assesses the science of innovation in Europe Strasbourg, 18 July 2012: Innovation has improved human living standards to an unprecedented level, and is the key to further progress; however it is a complex phenomenon that is not easy to understand and whose effects are unclear. This is the conclusion of the policy brief published by the European Science Foundation and STOA on innovation policy. The publication follows a ESF/STOA hosted conference on The Science of Innovation, which took place in Brussels on 28th February ...
Researchers identify mechanisms that allow embryonic stem cells to become any cell in the human body
2012-07-19
New research at the Hebrew University of Jerusalem sheds light on pluripotency—the ability of embryonic stem cells to renew themselves indefinitely and to differentiate into all types of mature cells. Solving this problem, which is a major challenge in modern biology, could expedite the use of embryonic stem cells in cell therapy and regenerative medicine. If scientists can replicate the mechanisms that make pluripotency possible, they could create cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer's, ...
A study shows that men and women have the same sexual fantasies
2012-07-19
A study conducted at the University of Granada have demonstrated that there are not significant differences between men's and women's sexual fantasies. The fact is that both sexes have intimate and romantic sexual fantaies involving their partner or loved one. In addition, men have more sexual fantasies (positive and negative) than women, which would confirm the old believe that men think more frequently about sex than women. To carry out this study, the researchers took a sample of 2250 Spanish people (49.6% mend and 0.4% women) aged between 18 and 73 years, who had maintained ...
NRL brings inertia of space to robotics research
2012-07-19
WASHINGTON –- The U.S. Naval Research Laboratory Spacecraft Engineering Department's space robotics research facility recently took possession of a one-of-a-kind 75,000 pound Gravity Offset Table (GOT) made from a single slab of solid granite.
To emulate the classical mechanics of physics found in space on full-scale replica spacecraft on Earth requires not only a hefty amount of air to 'float' the object, but a precision, frictionless, large surface area that will allow researchers to replicate the effects of inertia on man-made objects in space.
"We accomplish this ...
Do dolphins think nonlinearly?
2012-07-19
Research from the University of Southampton, which examines how dolphins might process their sonar signals, could provide a new system for man-made sonar to detect targets, such as sea mines, in bubbly water.
When hunting prey, dolphins have been observed to blow 'bubble nets' around schools of fish, which force the fish to cluster together, making them easier for the dolphins to pick off. However, such bubble nets would confound the best man-made sonar because the strong scattering by the bubbles generates 'clutter' in the sonar image, which cannot be distinguished from ...
Are cardiac risk factors linked to less blood flow to the brain?
2012-07-19
MADISON—Metabolic syndrome, a term used to describe a combination of risk factors that often lead to heart disease and type 2 diabetes, seems to be linked to lower blood flow to the brain, according to research by the University of Wisconsin School of Medicine and Public Health.
Dr. Barbara Bendlin, researcher for the Wisconsin Alzheimer's Disease Research Center and an assistant professor of medicine (geriatrics) at the UW School of Medicine and Public Health, said study participants with multiple risk factors connected to metabolic syndrome, including abdominal obesity, ...
Stanford-SLAC team uses X-ray imaging to observe running batteries in action
2012-07-19
VIDEO:
Johanna Nelson uses powerful X-ray imaging to study lithium-sulfur batteries, a promising technology that could some day power electric vehicles. Working with scientists at SLAC and Stanford University, Nelson took...
Click here for more information.
Most electric cars, from the Tesla Model S to the Nissan Leaf, run on rechargeable lithium-ion batteries – a pricey technology that accounts for more than half of the vehicle's total cost. One promising alternative ...
The future of biomaterial manufacturing: Spider silk production from bacteria
2012-07-19
A new video article in JoVE, the Journal of Visualized Experiments, demonstrates procedures to harvest and process synthetic spider silk from bacteria. The procedure presented in the video article revolutionizes the spider silk purification process by standardizing a key step known as "post-spin." In this step, silk molecules are stretched by a mechanical actuator to increase fiber strength. These mechanical improvements produce uniform spider silk and remove human error from the spinning process. As a result, the synthetic silk is much closer to the natural fibers produced ...
Story tips from the Department of Energy's Oak Ridge National Laboratory, July 2012
2012-07-19
BIOLOGY -- Waterlogged protein . . .
Proteins' biological functions, such as the ability to metabolize drugs in our bodies, are known to rely heavily on the presence of water, but mechanisms behind the relationship have remained unclear. In a paper published in Physical Review Letters, researchers from Oak Ridge National Laboratory have provided new evidence that suggests water is even more involved in protein dynamics than previously thought. Through a novel combination of supercomputer simulations and neutron scattering experiments, the research team found that the ...
Carnegie Mellon's George Loewenstein documents the pitfalls of personal loans
2012-07-19
PITTSBURGH— As an old proverb goes, "before borrowing money from a friend, decide which you need most."
New research from Carnegie Mellon University's George Loewenstein and the University of Vienna's Linda Dezsö provides evidence of the pitfalls of making or receiving personal loans. Published in the Journal of Economic Psychology, the study is the first to systematically investigate the contours and consequences of loans between peers, such as friends, siblings, and coworkers and shows how self-serving bias behavior affects future relationships.
"This research ...