Newt Gingrich speaks at town hall meeting in the Student Center at Louisiana Tech University,Tuesday, in Ruston, La. (Ben Corda/AP)

The top super PACs supporting Rick Santorum and Newt Gingrich appear to be low on funds.

Just-filed Federal Election Commission reports show Winning Our Future, the top pro-Gingrich super PAC, raised $5.7 million in February, including $5.5 million from casino magnate Sheldon Adelson and his family. But the campaign spent all of that and ended the month with $2.3 million cash on hand, before some tough contests in March in which it undoubtedly spent more.

Santorum’s top super PAC, the Red, White and Blue Fund, meanwhile, raised less than $3 million for the month and spent down its reserves to $365,000.

Santorums campaign and his super PAC combined to have less than $3 million in the bank at the start of the month, compared to nearly $18 million for Mitt Romney and his top super PAC, Restore Our Future.

That explains why Romney has benefitted from so much more ad spending this month.

For Gingrich, the question is whether his super PAC can even continue. Given that the Gingrich super PAC raised just $200,000 from people not named Adelson last month, it’s pretty clear that it needs the Adelsons to press on in a major way.

Thus far, there’s been no indication that the committee has gotten another infusion from the Adelson family, which has now pumped $16.5 million into Winning Our Future.