BERKELEY, Calif. Octopus sex is simple, dull and quick at least that's what scientists used to think. Instead, it turns out to be complex, sophisticated and rife with petty rivalries.
In the most detailed research ever conducted on this topic in the wild, biologists at the University of California at Berkeley focused on the mating behavior of the Abdopus aculeatus, one of more than 300 species of octopus. They were stunned at what they learned.
"The main surprise was the fact we had this idea that they were completely solitary, with interactions few and far between," said Christine Huffard, lead author on a study recently published in Marine Biology, a science journal. "But they interacted so much more than we ever expected."
She discovered that the males were very picky and discriminating, that the females would have sex with just about anybody, and that male competition for females tended to be violent and frequent.
"Christine actually followed the aculeatus from dawn to dusk," said Roy Caldwell, a co-author of the study and professor of integrative biology at UC Berkeley. "Nobody had done that kind of intensive field work on any octopus."
Huffard, who received her Ph.D. in biology from Cal, came across the species while she was living in Sulawesi, Indonesia, helping a friend with research.
"I happened to find them," she recalled. "It was completely serendipitous."
Caldwell said, "We went snorkeling and suddenly realized there were octopus everywhere."
They encountered four or five species the first afternoon. As a research subject, however, the Abdopus aculeatus won out because it was plentiful, lived in shallow water and was active during the day, Caldwell said.
Huffard spotted the eight-armed creatures on several islands, but many were in her front yard she was living on the water in a little wooden hut with no electricity.
She visited Indonesia six times and spent a total of 2 1/2 years there. In the course of the study which involved 789 hours of animal observation 167 individual octopuses were located and identified. Their body sacs were typically the size of a walnut, although a large female was as big as a small plum.
"I spent a year in the water," said Huffard, now a postdoctoral fellow at Monterey Bay Aquarium Research Institute in Moss Landing. "I got very, very pruney."
She observed the octopuses while snorkeling or walking on a reef flat, 10 to 17 feet behind them.
"As long as I stayed really still, they didn't seem to react to me," Huffard said. "They were used to seeing large things floating by dead pigs, dogs, chickens, rats. They were focused on each other and on potential predators they could recognize."
Besides being perceived as loners, Caldwell said, octopuses were seen as animals that didn't engage in courtship rituals but just coupled and got it over with. But he noted that fewer than 10 percent of octopus species have been studied, and only a half-dozen in any detail.
"Most studies are in the lab where they don't typically behave normally," Caldwell said. "People had known for a long time that you catch a couple of octopus, throw them in a bucket and very often they start mating right away."
Among the findings of the Cal team who studied the copulating cephalopods: They could identify each other by sex from some distance; smaller males would sometimes mimic the opposite sex to sneak a romantic moment with females that were under male guard; jealous males would stay in dens next to their mates for 10 days or more to defend them and sometimes would insert their mating arm in the female when she left her den to forage.
The researchers also observed males selecting their mates.
"Males prefer large females," Caldwell said. "If you're going to invest in guarding, you want to get the most bang for your buck."
The large females were preferred because they produced more eggs.
"It was very common to have a very large male next to a large female," Huffard said. "He could give her his sperm without leaving his den, and she didn't leave hers. Nobody has to give up their apartment."
Huffard witnessed some unusual moments. "In one case a male successfully chased away a rival even though his hectocotylus (mating arm) remained inserted in the female," she wrote.
She also saw a female cannibalize another individual.
Caldwell said the octopuses started mating three or four months before the female laid eggs. Three weeks later, when they hatched, the thousands of offspring swam away and the mothers died within a week, after just a year or so of life.
"She literally falls apart," he said. "Her skin loses color and she's just a ball of mush."
When asked if people thought her work was strange, Huffard laughed.
"Everybody thought I was crazy," she said. "Apparently on that island, spirits come out at noon and make a sound like silverware clanking together. They were really worried for me, and couldn't believe I was spending so much time in the water."
There was another problem, too.
"An octopus with seven arms is the devil, and many were missing one or more arms," Huffard said. "I was playing with fire apparently. Over and over, I'd hear, 'You came from America to do this?"'