Like actors in a scene from a bawdy farce, many squid don't know
whom to woo when the lights go down. Deep in California's Monterey Bay,
small squid belonging to the species Octopoteuthis deletron
suffer from frequent cases of mistaken identity, a new study suggests.
Males commonly try to mate with males as well as females, hinting that
in the dark, these invertebrates may settle for whatever squid passes
by. But their indiscriminate attention might improve the odds that they
are occasionally successful.
For years, biologists have had few opportunities to explore the lives
of deep-sea squid and their octopus relatives, save by dragging them up
in nets or harvesting them from the bellies of dead whales. Today,
crewless submarines plumb the depths of a handful of marine habitats,
including Monterey Bay. Often, the images these vehicles send back to
the surface paint a very different picture of the deep from early
land-based assumptions, says Michael Vecchione, a zoologist at the
National Marine Fisheries Service's National Systematics Laboratory in
Washington, D.C.
He points to certain squid that store ammonia in their tentacles,
perhaps for buoyancy. Because ammonia floats, many researchers figured
the eight-limbed critters swam with their tentacles over their heads
like cactuses. "But then we got to go down," he says. "It was the other
way around: They keep undulating their fins to maintain the arms-down
position."
Off the California coast, underwater cameras sometimes catch another
surprising sight: squid with what appears to be sea acne. Since 1992,
submarine surveys conducted by the Monterey Bay Aquarium Research
Institute in Moss Landing have spotted as many as 108 O. deletron
squid at play. These often-reddish animals—most about as big as a human
hand—troll about 400 to 800 meters below the sea surface. In a recent
survey, study co-author Hendrik Hoving, a marine biologist at the
institute, and colleagues discovered that many seemed to be dotted from
head to tentacles with tiny "white bulbs." Those bulbs, it turns out,
weren't blemishes but empty pouches that once contained squid sperm.
In the deep sea, scientists suspect that squid courtship involves
little romance and lots of pirate warfare. When males spot a passing
female, they smear them with sperm-laden globs called spermatophores,
using obscenely long organs. Once plopped down, the spermatophores
likely burst open, releasing clingy sperm pouches that then glom onto
the female's torso and tentacles. Hoving's team spotted these telltale signs of attempted liaisons on O. deletron females and males in seemingly equal numbers
, the group reports online today in Biology Letters.
In the dark, males and females may all look alike to a wandering
squid, Hoving suggests. Alternatively, because the largely solitary
males can breed for a short window of time only once in their lives,
they may drop their spermatophores onto every squid they encounter
rather than risk missing an opportunity to breed. Quick copulation is a
potentially safer mating strategy, too, he adds. Many squid species are
known cannibals, so it benefits males to "quickly deposit their
spermatophores and go away."
The team's findings are certainly strange, says Vecchione, who was
not involved in this study. Because scientists know so little about the
bizarre creatures that prowl the deep sea, this strategy may be more
common than many think, he says. "It's the biggest living space on
Earth," Vecchione says. But "it's the most poorly studied part." Correction: A previous version of this article
referred to octopuses that store ammonia in their tentacles for
buoyancy. The animals in question are squid. 作者: powercar 时间: 2011-9-23 10:59
：希望你爱我，不要只是因为我是地球上最后一只……
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