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Monterey Bay Aquarium Research Institute
The white dots on this female Octopoteuthis
deletron are embedded sperm. Males are often
recipients of these rocket sperm.
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By James Gorman, The New York Times, September 20, 2011
A
five-and-a-half-inch deep-sea squid that lives a solitary life up to half a
mile down in the dark waters of the Pacific Ocean is the latest addition to the
hundreds of species that are known to engage in same-sex sex.
Over the years,
scientists have added one creature after another to the list, making it clear
that although nature may abhor a vacuum, it seems to be fine with just about
everything else.
Male squid, for example, pay no attention to the sex of other squid.
Understandably so. They live alone in the dark, males and females are hard to
tell apart, and only occasionally do squids pass in the night. Far better to
risk wasting a few million sperm than to miss out on a chance to reproduce.
This is only one among many sorts of same-sex sexual behavior. In some
insect species, males engage in traumatic insemination, which is just what it
sounds like, of other males and females alike. Among mammals, bottlenose
dolphins and bonobos engage in lots of different kinds of sex. Male dolphins
pursue sex with males and females equally, but the females show a preference
for males. Bonobos pair off in all the combinations, often.
Laysan albatrosses form long-term female/female pair bonds, but for
them the point is raising chicks, not sex. If one female can arrange a quick
liaison with a male from another pair, the two females will tend the young.
Noah might well have had two female albatrosses on the ark.
But for sheer amazement, the mating behavior of the squid, Octopoteuthis
deletron, has to rank near the top. And the same-sex part is the
least of it.
For the record, Octopoteuthis is the first among the spineless masses
of invertebrates known to mate equally with males and females, Hendrik
J.T. Hoving and two colleagues report in their paper, “A shot in the
dark: same-sex sexual behavior in a deep-sea squid,” published, lurid title and
all, in Proceedings of the Royal Society: Biology Letters. No surprise given
its life in the deep.
The way the squid mate is something else. Little is known about the
details but it seems that the male ejaculates a packet of sperm at the mating
partner, and the packet turns inside out, essentially shooting the sperm
contained in a membrane into the flesh of the partner, where they stay embedded
until the female (if the shooter has been lucky) is ready to fertilize its
eggs. If males are the recipient of these rocket sperm, they are just stuck
with them. It is the kind of mating that would make a good video game.
And the visible evidence of those embedded sperm is what allowed Dr.
Hoving and his co-authors to document the squid’s mating choices. They pored
over video recordings acquired during almost 20 years of dives by remotely
operated vehicles sent out by the Monterey Bay Aquarium Research Institute,
where Dr. Hoving is doing research, to the deep Monterey Canyon off California.
One hundred and eight individual squid had been captured on video, and
of that number the scientists could determine the sex of 39 of them: 19 females
and 20 males. The almost equal numbers of males and females suggested that the
sample was representative. So when they found that of these 39, 9 males and 10
females had embedded sperm — roughly equal numbers — they concluded that males
were trying to mate equally with other males and females.
Dr. Hoving, who was leaving for research at sea himself around
publication time for his paper, was prepared for attention to the same-sex
behavior and was ready for people to conflate squid and human behavior and
announce the discovery of gay squid.
He fended off that notion, reiterating that the squid has no
discernible sexual orientation, and that a tentacled invertebrate that shoots
sperm into its mate’s flesh really has nothing to do with human behavior.
Marlene Zuk, author of the newly published “Sex on Six Legs: Lessons on Life, Love, and Language from
the Insect World,” and a biologist at the University of California,
Riverside, agreed. She has written about the evolution of same-sex sex in a variety of
insects and other animals, and she added a further caution.
Don’t imagine that squid are stupid, Ms. Zuk said, at least about
being squid. “The animal is not making a mistake. It’s not mistaken to deposit
sperm with another male,” because somehow, the behavior works, or natural
selection would have eradicated the behavior or the squid.
And,
she said, “we still have squid.”
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