• Sperm as superfood? It's a healthy snack for squid and other critters

    Julian Finn / Museum Victoria

    The southern bottletail squid occupies the waters off the coast of Australia.

    By Jennifer Viegas, Discovery News

    Certain females consume male ejaculate and sperm as if they were food, using the nutrients to fuel their own bodies as well as their eggs, according to new research.

    The study, published in the journal Biology Letters, adds yet another dimension to the battle between the sexes.

    "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," lead author Benjamin Wegener, a researcher at Monash University’s School of Biological Sciences, explained to Discovery News.

    Wegener said that ejaculate consumption is well-documented among numerous species. Humans are included in that group, but the behavior is not a standard part of our reproductive process.

    According to Columbia Health, human male ejaculate contains fructose sugar, water, ascorbic acid (a.k.a. Vitamin C), citric acid, enzymes, protein, zinc and more.  It reads like the list of ingredients for a protein-infused sports drink.

    Photos: Animals' mating strategies revealed

    Sperm consumption — as opposed to just ejaculate swallowing — in the animal kingdom "is far less common," according to Wegener. Species that exhibit this include carrion flies, picture wing flies, a strange marine invertebrate known as Spadella cephaloptera, a type of leech, a marine nudibranch and the southern bottletail squid (Sepiadarium austrinum).

    Humans again may swallow sperm, but it's not standard behavior during reproduction.

    It appears to happen a lot among squid, the focus of the new study. Wegener and his team discovered the behavior and tracked how the nutrients were utilized after consumption. It is the first time that the phenomenon has been observed in a female with external fertilization.

    "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 said. "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 help combat this problem, squid sperm and the sperm of many other animals may contain manipulative compounds that stimulate female reproduction. So far, more than 80 proteins have been identified in other types of sperm that could do the following: decrease female receptivity to further mating, encourage her to lay eggs sooner, stimulate ovulation and egg production, and affect how long females store sperm and affect egg fertility.

    Video: Four unusual animal mating habits

    Females, on the other hand, can control whether or not they will consume the sperm or ejaculate.

    This calls to mind numerous questions, such as whether females sometimes use males as a food source, whether females sample sperm to determine its quality, and whether they eat it to allow other sperm to fertilize eggs.

    Tom Tregenza, a professor of evolutionary ecology at the University of Exeter and director of research for CLES Cornwall, told Discovery News that it’s been known for some time that insects get nutritional benefits from eating male sperm packets (squid, certain insects and other species encase sperm in a membrane-sealed, spring-loaded package). He said that "this finding of exactly the same sort of thing having evolved completely independently in such a distantly related group is really fascinating."

    He agrees that the behavior can put pressure on the males, which have to balance providing enough sperm for fertilization, but perhaps not so much that females start to rely upon it as a regular "tempting meal."

    "As the authors point out," Tregenza added, "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."

    Copyright 2013 Discovery Communications LLC.

  • More acidic seas could mean big trouble for squid

    Roger Hanlon

    Squid such as these longfins.could be threatened if carbon dioxide continues to raise acidity levels in our oceans.

    By Stephanie Pappas
    LiveScience

    Squid could be in trouble as the oceans grow more acidic, new research finds.

    As humans pump carbon dioxide into the atmosphere, the oceans absorb about a third of the greenhouse gas. This buffers terrestrial creatures from even more extreme effects of climate change — without the oceans, Earth's atmosphere would contain far more than the approximately 400 parts per million of carbon dioxide that it does today. However, the dissolved carbon dioxide makes the oceans more acidic, possibly affecting thousands of marine species.

    Squid, it seems, may be among the most vulnerable, with consequences that could trickle through the marine ecosystem. A new study published Friday in the journal PLOS ONE finds that squid raised in more highly acidified ocean water hatch more slowly and are smaller when they hatch than squid raised in ocean water at today's pH levels. The acid-exposed squid also have abnormal statoliths, which are internal, calcified structures that function like the mammalian inner ear to help squid keep their balance and orient themselves.

    "We're worried these guys won't be able to swim and behave properly," study researcher T. Aran Mooney, a biologist at the Woods Hole Oceanographic Institution in Massachusetts, said of the acidified squid. [Release the Kraken! Photos of Giant Squid]

    Acidifying oceans
    Mooney and his colleagues trawled for Atlantic longfin squid (Doryteuthis pealeii) from the Vineyard Sound off of Massachusetts. The researchers brought the squid to the laboratory and kept some in tanks with a pH of about 8. On the pH scale, 7 is neutral, and 8 slightly basic. The open ocean today has a pH of about 8, which is a decline of about 0.1 pH units since pre-industrial times, an increase in acidification attributable to carbon dioxide produced by humans.

    Researchers kept the rest of the squid in tanks with a more acidic pH of about 7.3. Climate projections suggest the open ocean could reach this level of acidification in about 100 to 200 years, Mooney told LiveScience. In coastal areas, where acidity is more variable, a pH of 7.3 sometimes already occurs.

    The researchers allowed the squid to mate and lay eggs in the tanks, and then tracked how long it took those eggs to hatch. The scientists found that squid raised in a more acidic environment developed more slowly, emerging from their eggs about 24 hours later, on average, than the squid placed in normal ocean conditions. The delay is bad news for baby squid, which are defenseless fish-food in their egg stage.

    "The longer you're an egg sitting there, the more likely you are to get eaten," Mooney said.

    Key to the ecosystem
    The squid reared in acidified water were also smaller than normal when they hatched, with an average body length of 0.07 inches (1.78 millimeters) versus 0.071 inches (1.81 millimeters) for squid hatched in normal conditions. That smaller size, again, could make squid more vulnerable to predators, Mooney said. The miniaturized squid might also have a harder time swimming and migrating than their larger brethren.

    Finally, the researchers dissected some of the squid at each day of development to examine the stony statoliths that give the animals their equilibrium. The scientists found that the statoliths of acidified squid were irregularly formed and porous, suggesting that the water pH disrupted the development of these structures.

    Squid are a keystone of the ocean ecosystem, Mooney said. They're important prey for animals ranging from fish to marine mammals to sea birds. They're also an important food source for humans, who pull about 3 million tons of squid from the ocean each year. Thus, damage to squid populations could reverberate throughout the ocean ecosystem.

    The researchers don't yet know, however, what threshold acidification would have to cross to cause damage to squid; nor is it clear how other squid species will react. The next step, Mooney said, is to raise squid in multiple pH levels to figure out the effect of each "dose" of acidification.

    "Now we're kind of filling in those gaps," Mooney said.

    Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook and Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Captured deep beneath the waves: Giant squid filmed in natural habitat

    Scientists say they have captured video of a giant squid in its natural habitat deep in the ocean for the first time. NBCNews.com's Dara Brown reports.

    By Arata Yamamoto and Peter Jeary, NBC News

    The world's first moving images of a giant squid living in its natural habitat have been captured by a team of scientists more than half a mile below the surface of the Pacific Ocean.

    The ghostly pictures of the 10-foot-long giant squid were recorded from a state-of–the-art submersible carrying a three-person team of Japanese zoologist Tsunemi Kubodera, a camera operator and the submersible’s pilot, who made around 100 dives during an expedition last summer.

    Although small by giant squid standards – the largest ever caught measured 59 feet – it was the first time a live giant squid had been caught on video deep in the ocean.

    Kubodera, from Japan's National Museum of Nature and Science, credited the success to the submersible’s silence and hi-tech lighting.

    "A giant squid would never appear before a pool of light, that possibility is extremely slim", he told NBC News. "That's why we had to use lights that they wouldn't be able to detect. In fact, they're lights even humans wouldn't be able to see either."

    “If you try to approach making a lot of noise, using bright lights, then the squid won't come anywhere near you," he added. “So we sat there in the pitch black, using a near-infrared light invisible even to the human eye, waiting for the giant to approach.''

    'It was stunning'
    On one dive in July 2012, near the Ogasawara islands, 620 miles south of Tokyo, they finally had their close encounter more than 2,000 feet down and followed the creature even deeper.

    “This was the first time for me to see with my own eyes a giant squid swimming,'' Kubodera said. “It was stunning. I couldn't have dreamt that it would be so beautiful. It was such a wonderful creature.”

    NHK/NEP/Discovery Channel via Reuters

    A giant squid is seen in this video still talken near the Ogasawara Islands in July 2012.

    The squid was missing its characteristic two longest tentacles – and scientists don’t know why. Marine biologists said if that pair of tentacles had been intact, the creature would probably have measured up to 23 feet long.

    Kubodera’s deep-sea expedition was the culmination of a 10-year project by Japanese broadcaster NHK to capture pictures of the mysterious creature in its habitat. An  ultra-sensitive high-definition camera was developed to operate at the ocean depths, using special light that was invisible to the sensitive eyes of the giant squid.

    NHK will air its video footage in Japan in a prime-time documentary entitled "Legends of the Deep: Giant Squid" on Jan. 13. It will also be shown on the Discovery Channel on Jan.  27.

    Reuters contributed to this report.

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