Female squids, probably due to a lack of access to protein and vitamin shakes, seem to have made sperm its new favorite drink.
A recent study, conducted by a scientists at Monash University's School of Biological sciences, have discovered a new way by which the female southern bottletail squid maximizes its chances of producing offsprings - by ingesting the sperm ejaculated by the male.
This study, which is now published in the journals Behavioral Ecology and Biology Letters, was led by a PhD student, Benjamin Wegener.
While it's already well-known that sperm does contain some of the most beneficial and essential nutrients for the body, some animals seem to have taken it seriously. And it's not just the squid; many other animals like carrion flies, picture wing flies, and some species of leeches too, consume the sperm ejaculated by the male.
While the bottletail squid uses the energy derived by the sperm consumption to fuel its own body, and to enhance the reproductive process, other animals may not do so.
"Sperm consumption -- as opposed to just ejaculate swallowing -- in the animal kingdom "is far less common," Benjamin explained. If males have their sperm consumed, rather than used for egg fertilization, they will lose that reproductive opportunity. Therefore, it is in the male's best interests to try to ensure at least some of his sperm reaches the female's eggs."
Apparently, after the female consumes the sperm, she stores it in an external fertilizer- a pouch below the mouth. This activity may lower the chances of the male fertilizing the egg, as this external fertilizer tends to decrease the viability of the sperms, the study explains.
"This is an important distinction, as even if the female consumes some of the ejaculate in those internal fertilizers, at least some of the sperm remains inside in the reproductive tract," he added. "For an external fertilizer with short-term sperm storage, if the female doesn't lay eggs in time, the male loses his chance to fertilize the eggs."
To overcome this issue, the animals seem to have evolved, and their sperms may now contain certain compounds or substances that may help stimulate egg production in the female, decrease her chances of mating with other males, and determine how for how long the females could store the sperms in the external fertilizers.
This may prove to be a problem in the future; especially if the females start relying on the sperm as a regular meal.
"As the authors point out," Tom Tregenza, professor of evolutionary ecology from the University of Exeter, explained. "She might even choose to eat the sperm packets from less attractive males and use the sperm from more attractive ones for fertilizing her eggs."