The recent success of the movie “Twilight” showed the power of both a vampire romance and the tween dollar.

A big part of the movie’s success — it had the fourth most lucrative weekend opening of the year — came from female moviegoers in the teen and so-called tween demographic, usually described as being between 8 and 14.

When the movie’s female lead, Kristen Stewart, appeared last month at a store in Paramus, N.J., hundreds of star-struck girls waited for hours for an autograph and a few seconds of time with the actress.

Paul Pflug, spokesman for Summit Entertainment, the film’s producer and distributor, said the movie showed that the girls’ young teen demographic — and younger — is worth targeting.

“I think it made people aware that this really is a segment of the audience that would go out and support a product that’s made directly for them,” he said.

That wasn’t news to fashion retailers, for whom malls present a particularly sweet spot.

EPM Communications Inc., a New York-based market research firm, estimates tween spending power nationwide at $43 billion.