LOS ANGELES » Heading into the all-important summer moviegoing season, two converging box-office trends are startling studios: Women are driving ticket sales to a degree rarely, if ever, seen before, while young men – long Hollywood’s most coveted audience – are relatively AWOL.

With the release of "The Divergent Series: Insurgent" over the weekend, women have delivered the three biggest live-action openings of the year. The audience for "Insurgent," which took in an estimated $54 million from Friday to Sunday, was 60 percent female. The opening-weekend crowd for "Fifty Shades of Grey" was 67 percent female, and women made up 66 percent of the audience for "Cinderella."

It would be easier to dismiss those percentages as a fluke – three big female-oriented movies just happened to arrive in proximity – if a parade of movies aimed at young men had not bombed over the same period. Among the carnage: "Jupiter Ascending," "Seventh Son," "Hot Tub Time Machine 2," "Chappie" and, over the weekend, Sean Penn’s "The Gunman."

The shift has been noticeable enough to prompt movie executives and producers to ruminate about the causes and consider whether the big film factories should recalibrate their assembly lines. Counting on the stability of young men, studios have nearly 30 superhero movies on the way by the end of 2015, each costing well over $100 million to make. But young men are more easily distracted by other forms of entertainment, and women may now be the more reliable opening-weekend audience.

"You can never put your finger on it entirely, but you have to ask the questions," said Dan Fellman, president of domestic distribution at Warner Bros. "Is this just the cyclical nature of the movie business? Or does it point to a more serious shift in habits?"

The uncertainty comes as Hollywood tries to bounce back from a terrible 2014. Admissions fell 6 percent at North American theaters last year, to 1.27 billion, compared with the previous year; ticket sales declined 5 percent, to $10.4 billion. Ticket sales are up about 4 percent so far in 2015, but the high-risk summer months – packed with male-centric movies like "Mad Max: Fury Road," "Terminator: Genisys" and "Ant-Man" – usually set the pace for the year.

Studios awoke to the power of female ticket buyers in 2008, when the "Twilight" action romances became a global phenomenon. Since then, women have turned films like "The Hunger Games," "Bridesmaids" and "Frozen" into smash hits.

But the muscle of women at the multiplex has recently gone "from sporadic to continuous," said Paul Dergarabedian, a senior analyst at Rentrak, which tracks box-office data.

Young men used to be Hollywood’s most reliable audience, in part because they tended to be less discriminating than women. "No story? No problem! As long as people got blown up, guys showed up," Dergarabedian said.

But studio research executives say young men are the most likely to be lured by alternative activities like video games, sports and YouTube comedy clips. Research indicates that teenage boys in particular do not want to be told when and where they have to consume entertainment, which makes herding them into a movie theater difficult.

In contrast, "teenage girls still seem to want the experience of going to the movies as a group," said Terry Press, president of CBS Films, which recently hit specialty film pay dirt with "The DUFF," an $8 million comedy about a high school pecking order that is closing in on $35 million in ticket sales, overwhelmingly because of female moviegoers.

The recent box-office gyrations also expose a flaw in studio strategy, analysts say. At a time when so many movies turn themselves inside out trying to attract everyone (a plan that could be summed up as "wide and shallow" in industry parlance), it is clearly possible to fill a big tent by picking a couple of demographics, in particular underserved ones, and superserving them ("narrow and deep").

"Cinderella," for instance, was not aimed at everyone. But by being a perfect version of something narrower – a costume romance aimed at mothers and girls – "Cinderella" has sold a stout $122 million in tickets in the United States and Canada in just two weeks. ("Empire," aimed initially at often-ignored African-American viewers, offers a corollary example from television.)

"What has been happening at the box office sends a message loud and clear that you don’t need four quadrants to be a massive hit," said Phil Contrino, chief analyst at BoxOffice.com. In movie jargon, a four-quadrant movie is one that attracts men and women, young and old (Hollywood considers anyone over 25 to be old).

When it comes to the male-female divide, the recent overreliance by studios on visual effects may play a role. The bar for visual effects has been raised so high, experts say, that nothing less than a prolonged smackdown between a raging Hulk and a supersize Iron Man has much hope of turning male heads.

"You used to be able to go to movies and see something that you never saw before – a giant shark, dinosaurs," said Allison Shearmur, a producer of "Cinderella" and a former senior executive at Lionsgate, Paramount and Universal. "But spectacular visual effects have become routine."

Shearmur continued: "So what does that mean? It means that we’ve got to make more movies that have a compelling core story. The audience still comes when the story is strong, when we can laugh or cry or be afraid in a theater together."

Fellman of Warner Bros. predicted that boys would return en masse for coming PG-13 event movies like "Furious 7" and "The Avengers: Age of Ultron."

"Outside of ‘American Sniper,’ which started older and got younger, and ‘Kingsman: The Secret Service,’ there has been a noticeable lack of young men," Fellman said. "But a lot of the so-called guy movies recently have been rated R, and you lose a lot of tweeners that way," he noted.

Warner will add another R-rated comedy to the mix on Friday with "Get Hard," which has been generating solid interest from men in prerelease surveys.

But the success of Hollywood’s summer box office may well rest with women. Nestled among the superheroes and action movies are an unusually large number of pictures aimed at a female audience, including "Pitch Perfect 2," an estrogen-heavy musical comedy; "Spy," an action comedy starring Melissa McCarthy; "Pan," a splashy adaptation of the Peter Pan story; and the male stripper sequel "Magic Mike XXL."

"The whole notion of the summer blockbuster has always been built around young men," Dergarabedian said. "I think we’re about to see that change. The clout and importance of the female audience has never been bigger."

Brooks Barnes, New York Times