Kraken
Page 14
“They really are moving,” he said.
As the master of ceremonies, he wasn’t quite as calm as before.
“This thing has been frozen for two years, and there’s something moving inside it …,” he said, as though talking to himself.
Some kids talked about stuffing the jumping objects into the storage closet.
“Come in tomorrow, and open the storage closet, and out they’ll pour,” one said. These kids had seen a lot of horror movies.
The “jumping beans” turned out to be packages called spermatophores. Spermatophores are densely packed semitranslucent capsules that become filled with sperm. Spermatophores embed themselves into the flesh of female squid, then bide their time. They are also capable, apparently, of dancing on metal when the occasion calls for it. At some point, with enough oxygen and under the right circumstances (scientists are not entirely sure what those circumstances are) the capsules explode. The sperm is finally free to ooze wherever it can.
Most cephalopods use spermatophores in reproduction, but the strategy as to how to use them varies, sometimes considerably, from species to species. Spermatophores from Dosidicus have “tabs” on their ends, proteins that are capable of becoming chemically active and agitated when the time is right. Apparently, during Rob’s classroom dissection, the time was right. Hence the seemingly suddenly alive “things” with the ability to wiggle and jiggle.
Squid sex is not a pretty sight. It’s not even a salacious, titillating, or scintillating sight. In fact, most of us probably wouldn’t recognize sex in squid for what it is even if we were fortunate enough to see it. Of course, that’s my opinion. Not everyone agrees. Gilly said: “It’s not that different from humans, except that they use their hands.” Then, laying a finger beside his nose, he paused. He thought a bit: “Maybe it’s more like artificial insemination.”
Squid and humans may share a similar neuronal design, but when it comes to sex, we share only the most basic sperm-meets-egg stuff. The physical act itself is quite different. And the more I learned about squid sex, the more I thought that our differences might be a good thing. For humans, at least.
In most species of squid, the male has a special spoonlike tool, called a hectocotylus, on the end of one of its arms. With this tool, the male takes some of its own stored spermatophores and places them somewhere on the female’s body. Where the male places his sperm seems to be species-specific.
California market squid, the kind caught in Monterey Bay and sold to China and Japan, is the West Coast equivalent of Loligo pealei. Because it’s a commercially valuable species and its numbers seem to be declining, we’ve spent a lot of money learning about its lifestyle preferences. The male usually places the sperm inside the female squid’s mantle. The idea is that when the female expels her eggs, some of those eggs might brush past the male’s spermatophores and the male might get lucky. His genes get to wiggle their way into the next generation.
This doesn’t seem to me to be a very satisfactory arrangement for the male. Even if he does the dirty deed and succeeds in stuffing the sperm somewhere on the female’s body, he has no guarantee that it’s his sperm that will win the ultimate race to create the next generation. As far as science knows right now, there’s a strong element of chance in the male squid’s approach. Of course, some observers might say that’s true for male humans as well.
In general, even in market squid, we know very little of the details of squid sex, but which sperm are successful appears to be at least in part a matter of accident. Female choice seems to have little to do with the final product, although there may be a way in which the female squid exercises her judgment that we don’t recognize. As any guy knows, female choice is not always easy to discern. Rather early on we understood that the male peacock’s tail feathers were the lure for the peahen, who chooses which male will finally get to fertilize her eggs based on the flamboyance of the male’s tail. But female decision-making isn’t always that obvious. Evolutionarily speaking, it doesn’t make sense that success for male squid is a mere matter of chance. There ought to be some kind of fitness test that helps the female discern which sperm is best, some way for the male to prove that he’s stronger or smarter or a better swimmer than the other guy, so that the female will choose him.
Market squid do exhibit at least one male sex behavior that has also been seen in male humans: Some male market squid become “guards.” That is, after they deposit their sperm in the female’s body, males may expend a good deal of effort in trying to keep the other guys away. I talked to market squid expert and Gilly colleague Lou Zeidberg about this, and his description reminded me of Joe DeGiorgis’s “bar scene” description of mating male Loligo pealei.
“Guard males” are not always successful. Zeidberg has seen “sneaker male” mating in his market squid, both while watching market squid at sea and by studying many incidents recorded by undersea video equipment. He’s seen that the larger males stick around to ward off other males. But he’s also seen the little guy make his own opportunities. While the big males fight it out, a little male might zip in and stash his stuff.
So it turns out that the wimpy kid is not so wimpy after all. Zeidberg’s colleague Miriam Goldstein calls the sneaker-male tactics “drive-by sperming.” Using this strategy, the smaller male deposits its sperm in a pocket near the female’s beak area, which turns out to be a location the bigger guy isn’t paying that much attention to, since he’s spending much of his time trying to keep the other bigger guys away from the female’s mantle. The female stores that sneaker sperm until she’s ready. This storage may occur for a period of hours, days, or even longer, Zeidberg suspects. When the time comes, the female market squid exudes eggs from her oviduct, which are then fertilized by sperm from the guard male. Then she holds those eggs in her crown of arms and stuffs them into an egg sac. This act occurs right near where the sneaker male left his sperm. That, said Zeidberg, is probably how at least some of the sperm from the smaller animals gets into the next generation of market squid.
“We’ve done paternity tests,” Zeidberg said.
At least in California market squid. Zeidberg and his colleagues found out that roughly 80 percent of a female’s eggs are fertilized with sperm from the guard male, but about 20 percent or so are fertilized via the drive-by strategy. And so science has proven once and for all that the wimpy kid does get the girls.
I asked Zeidberg why a species would adopt two different strategies.
“It’s sort of like hedging your bets,” he said. “You’ve got two different life strategies. One is really good for most of the time.” But if something changes in the ecology of the ocean, the other style of mating may provide some important kind of backup to the species population as a whole. Why the other strategy for squid mating might one day be needed, Zeidberg didn’t know, but he explained how a similar situation—two lifestyles in one salmon species—allowed for species survival. Most salmon swim out to sea, he explained, but a small portion may stay in nearshore waters around the mouth of the river where they spawned. If something at sea—some kind of ecological change, perhaps, or a mass of floating toxic plastic—wipes out the salmon, there will still be this small group of less adventurous salmon left to start up a new population.
So, variety really is the spice of life. In keeping with that philosophy, there exist many species-dependent variations of squid sex. The eccentric, semi-preternatural, bioluminescent, eight-armed, deep-sea Taningia danae may weigh several hundred pounds and perhaps reach twice the size of Julie’s squid. Taningia’s strategy for love makes drive-by sperming look downright gentlemanly. This species is rarely seen, but Dutch scientist Hendrick Jan Hoving has studied several female carcasses. He found a number of flesh wounds containing spermatophores in a variety of places on the females’ bodies. He wrote that he found said wounds “suggestive.” Apparently, the male Taningia uses its sharp beak to slash the female’s flesh. The animal then inserts the sperm into the wound. Is this love?
Then there’s the paper nautilus, a.k.a. argonaut, actually an octopus rather than a squid or genuine nautilus. “What’s so cool about the argonaut,” said Danna, “is that the males are about a tenth the size of the females. And there’s this special arm, a hectocotylus, that the male has for passing spermatophores. The arm in the male is the same size as the male’s whole body, or even bigger, maybe even twice the size, and when it’s time to mate the arm breaks off and swims to the female, holding the spermatophores. For years, people looked for the male of the species and couldn’t find it, but they found these females and thought there were big worms inside them, and they named the worms ‘hectocotylus.’ So that’s how the hectocotylus got its name. Only then they found out it wasn’t a worm but part of the male, so instead of meaning a parasitic worm, the word came to mean a specialized arm.” Truth to tell, there may be no one on the planet who knows more about squid sex than Danna Staaf.
Little is known about the physical act of sex in Dosidicus, although in May 2004, in the Sea of Cortez near the southern tip of a group of small islands, Gilly witnessed twice what he thought might have been a mating pair of Dosidicus. He and a group of colleagues were standing on the deck of the research boat on a very still night when the water was dead calm. Floating motionless right near the boat he saw a large squid, which he thought was probably the female. The tips of its fins were above the water’s surface. “In its arms, it was holding the smaller squid, which if they were mating was hopefully a male,” he said. “There was no struggling. It didn’t look like the larger one was trying to eat the smaller one. I could see, flickering near the side of the big squid’s arms, the tip of the smaller squid’s arm coming out, stroking, tickling the female’s arm.”
The animals hung there together for about ten or fifteen minutes, then just passively sank beneath the surface.
“It’s not something I’d seen before,” he said. “I’d seen squid at the surface before, but not two of them, holding each other.”
“Were they mating?” I asked.
“I don’t know what else they would have been doing. It’s sort of a romantic notion, to think they were mating. I suppose I could have captured them and looked for eggs and sperm, but it wouldn’t have been a very popular thing to have done on that boat. We were outnumbered by women at the time. It was very beautiful, so I think it was best at that point just not to have discovered too much.”
In the case of squid, the eons have allowed for the evolution of all sorts of ways to enjoin sperm with egg. As the scientists say, in the ocean there are whole libraries of genes with almost limitless strategies.
We, of course, have our own strategies for sneaker males. In nineteenth-century France, for instance, upper-class gentlemen, who regarded themselves as quite civilized in matters of female choice, respected the custom of heure d’amour, the hour just before dinner when a husband would be wise not to visit his wife’s boudoir. Squid and most other cephalopods have their own heure d’amour, but combat for the ladies’ attention may sometimes be anything but civilized. In some cephalopod species, the fight for the female is sometimes to the death. But even more striking is the fact that even when the males win, they die anyway. So do the females. They release their eggs and drift off into the Big Sleep. Cephalopods in general get one, and only one, heure d’amour. After the act’s over, it’s all over for the squid. This is another reason why it doesn’t bother me much that we don’t have much in common with squid when it comes to the physical act of love.
Humboldt reproduction was also a point of interest on Julie’s research cruise. By the time darkness fell on the research boat that November evening in Monterey Bay, the crew had pulled in a good many specimens. Dosidicus tentacles slid everywhere over the boat’s deck. The place seemed to writhe with snakes. This was no place for Indiana Jones. When Gilly pulled in one of the animals and dropped it on the deck, a tentacle immediately began slithering over his boot and up his leg. (If you go Dosidicus fishing, it’s probably best not to wear shorts and sandals.) After about sixty or so animals had been pulled up, the crew was tiring. It’s no easy thing to reel in animals that size from hundreds of feet below.
Gilly placed the last of the whole squid in plastic bags in the cooler for use in his Squids4Kids program, and Julie began to slice and dice the remaining squid for research purposes.
Holding the flesh of the mantle apart with her right hand, she scooped the spermatophores out of one squid’s body with her left.
“This one’s a male,” she told Gilly.
“Save some of the mantles,” he answered. Voicing his epicurean side, he added: “I want to smoke some again.”
Behind her, Rob officially pronounced himself done, after lugging his last Dosidicus on board.
“Packing it in, Rob?” Gilly asked. “You don’t have to quit just because I did.”
Julie turned around in surprise as Rob’s last catch let loose from the siphon and she was showered with cold seawater.
This made his total for the night around twenty, and even the effervescent Rob was exhausted.
Julie began processing stomach after stomach, cutting them out of the animals’ innards and putting them into plastic bags. In a few days, she would head over to John Field’s government lab to look at these samples again.
After a respite of about thirty seconds, Rob headed over to help Julie with her task and to get an advanced lesson in Dosidicus dissection. Julie and Rob checked the female carcasses to see if they’d been mated. In the case of Humboldt squid, the spermatophores embed themselves into the flesh around the female’s mouth. Then they work their way into her flesh. They remain there, looking like fairly innocuous pimples, until the female is ready to spawn.
Julie wanted to gather data on how many of the squid they’d pulled in that night had been mated. She and Rob examined the flesh carefully around the animals’ mouths, and sure enough, she was able to point out to Rob several “pimples” around some of the females’ mouths.
Julie pulled out more spermatophores to show him. They were, as they had been in Rob’s high school classroom months earlier, long and translucent, white and plentiful and restless in her hand. Covered with some kind of mucuslike material, they slid over her palm and dropped onto the boat deck.
Sex was not initially a part of the animal world. The very first species of animals that evolved used techniques to reproduce that did not involve the ritual interactions of males and females. Amoebas, for example, reproduce by just dividing. In theory, this is a better approach in some ways than what we’ve got. It certainly requires a lot less emotional angst.
Nevertheless, around a billion years ago, give or take a few million years, the idea of male and female took shape on planet Earth. No one can really explain scientifically why this happened, although a lot of intriguing explanations have been proposed. Chris Adami of the California Institute of Technology, who uses computer programming to study genetic recombination, suggested not so long ago that life on our happy Eden, planet Earth, was disrupted not by an apple, but by some kind of mass disaster like a large meteor impact. Genes could have been juggled around. Such a disaster could have caused a higher rate of mutation in our amoeba-like ancestors and led, eventually, to the solution of genetic recombination and male and female.
Whether or not this was a good idea, in the human species at least, remains to be seen.
A few weeks after the cruise, Julie headed over to John Field’s research lab in Santa Cruz, on the northern coast of Monter
ey Bay. She was there to study the stomach contents removed from the squid caught and dissected during the evening research cruise. They were trying to find out about what squid of various sizes ate during various seasons, a task Field had been at for years. Julie hoped that some of the data would provide information for her thesis. The next hours would be filled with a variety of tasks that would wind up filling Julie and John Field’s master files with endless columns of numbers that could result in a solid theory as to why Dosidicus had so suddenly appeared in such great numbers.
Field had taken the frozen stomachs out of the freezer a day earlier. The team needed to weigh the stomachs with everything still inside, then take all the stomach contents out and weigh just the stomach lining. This would also provide the figure of how much the contents weighed.
Then came a task something like “panning for gold,” as Julie described it. She placed the thawed stomach contents in a sieve and placed the sieve under running water. “This washes most of the small stuff away, and you’re left with the bigger stuff—eye lenses, bones, otoliths. You find parasites, shells from things they’ve eaten, and there’s always some stomach junk—unidentifiable juices, stuff like that.”
Each piece of detritus must be pulled out and identified. The otoliths—fish organs similar to squid statoliths—must be pulled out and cleaned off. Otoliths (and statoliths) are unique to each species, so scientists can use them to identify what kinds of fish a squid might be eating. Some otoliths may be easily visible, but others are quite tiny, perhaps because they come from a young fish, or perhaps because they come from a species of fish in which otoliths are routinely small. Each otolith must be identified and documented. There are scientists who have devoted their entire careers to identifying and cataloguing various otoliths and statoliths. Field has thick identification books beside him at his microscope in the lab, in case he comes across an otolith he can’t identify. That doesn’t happen often, though, since after years of studying squid stomach contents, he has become somewhat of an expert in his own right. Every once in a while, when he can’t make an identification even by using the catalogues, he might pack up a strange otolith and mail it to an expert for a final ID. Examining the contents of each individual stomach requires anywhere from twenty-five minutes to an hour.