Garbage dinners and stale water make life tough in the deep sea
© 2004 MBARI
Vampire squid live slow. Even their gonads, it turns out, take vacations.
Any information about their reproduction is prized, because no one has seen the deep-sea dwellers even swim close enough to each other to flirt. Studies of fished-up specimens offer clues. But they can’t solve puzzles such as how sperm gets into female storage pouches, one beside each of her large blue eyes.
What little is known about the biology of Vampyroteuthis infernalis suggests a low-speed life scrimping along on modest-at-best resources, says Henk-Jan Hoving with GEOMAR Helmholtz Center for Ocean Research in Kiel, Germany. The species frequents oxygen-starved zones in temperate and tropical waters and has the most sluggish metabolism yet measured among cephalopods. Also, the so-called vampires don’t drink blood. Often they dumpster dive, gleaning and swallowing wads of sinking fecal pellets and other debris.
This leftovers lifestyle helped Hoving make sense of surprises he found in 43 preserved female vampire squid specimens. In each, he found mature ovaries with the expected divots left behind by egg release. Yet some of these obviously working ovaries held no new eggs approaching perfect plumpness for release. The rush to reproduce had paused. In squid, he says, “that’s something we had never seen before.”
Related species reproduce in one headlong rush before dying. Called semelparity, this single blowout of procreation shows up in organisms from salmon to garden squash vines. Among species of squid, octopus and cuttlefish, the vampire looks like the first clear exception, Hoving and his colleagues report in the April 20 Current Biology.
About male vampire squid, not much is known. But Hoving can say that they don’t produce the most famous of squid sperm masses: grenadelike ones that, when free of the male’s body, convulse so violently they drill sperm millimeters deep into heads, arms or any soft tissue in range. Vampire sperm clumps instead just break apart. Whether males need time-outs when producing the sperm parcels, no one knows.
SLOW LANE Despite its name, the vampire squid lives a sluggish, unassuming life deep in murky ocean waters. It feeds on sinking detritus, not on blood. Credit: MBARI
H-J.T. Hoving, V.V. Laptikhovsky and B. H. Robison. Vampire squid reproductive strategy is unique among coleoid cephalopods. Current Biology. Vol. 25, April 20, 2015, p. R322. doi:10.1016/j.cub.2015.02.018.
H.J.T. Hoving and B.H. Robison. Vampire squid: detritivores in the oxygen minimum zone. Proceedings of the Royal Society B. Vol. 279, November 22, 2012, p. 4559. doi: 10.1098/rspb.2012.1357.
H.J.T. Hoving and M. Vecchione. Mating behavior of a deep-sea squid revealed by in situ videography and the study of archives specimens. Biological Bulletin. Vol. 223, December 2012, p. 263.
S. Milius. The real vampire squid. Science News Online, June 25, 2012.