If the language Apple is using to promote this year’s Worldwide Developer Conference is any indication, then Cupertino’s betting that the only thing developers will like better than the individual tastes of iOS and Mac OS X is those two great tastes swirled together.

According to the company’s press release on Monday morning, this year’s WWDC attendees will be treated to “the future of iOS and Mac OS.” Rumors abound whether or not new hardware will make an appearance as well, but with major updates to both of its platforms on the docket, it seems unlikely Apple will want to crowd the stage with too much else.

In the past, Apple’s two operating systems have often taken parallel tracks, with iOS getting a preview event in the spring and Mac OS X, on its less frequent update schedule, being shown off at WWDC or in a separate Mac-related event, like Apple’s Back to the Mac shindig from last year. I’d venture to guess that Apple’s announcement on Monday, positioned at a time when—if the pattern of prior years had held true—we’d be expecting an iOS preview event, was designed to let us know that we’ll see neither hide nor hair of iOS 5 before June.

It seems clear that, going forward, Apple largely envisions the two operating systems as being different facets of the same fundamental experience. For evidence, look no further than the image on the front page of Apple’s WWDC site, which features what appears to be a mingling of iOS and Mac OS app icons combining to fill in an Apple logo.

A glance at the list of tracks for sessions and labs—Application Frameworks; Graphics, Media, and Games; Developer Tools; Internet and Web; and Core OS—would seem to confirm this. Every single one of the tracks mentions and is applicable to both iOS and Mac OS X; and that’s little surprise, given that Apple uses the same underlying technology in both of its operating systems. Plus, the Mac has returned as a category in the Apple Design Awards, after an absence last year that left many OS X developers irked. (There is a catch however, as entries this year must be available on the Mac App Store.)

Last year, though, was clearly the year of iOS—literally, in fact, given that it was at 2010’s WWDC keynote that Steve Jobs announced the new moniker for Apple’s mobile operating system. That was on top of Jobs’s unveiling of the iPhone 4 in the same presentation, the already released iPad, and an iOS 4 preview event in April.

This year, though, it’s almost the opposite situation: While the future of Lion has been well and truly teased, Apple’s kept a pretty tight lid on anything related to iOS 5 or the future of the iPhone. Even the company’s iPad 2 event in March, which previewed iOS 4.3, didn’t show off much in the way of new software features.

The previews of Lion have shown that the company is serious about integrating features from iOS back into Mac OS X. Might we see a reciprocal effort, with iOS 5 taking advantage of more functionality that originated in Mac OS X, or offering closer ties to the desktop version of the operating system?

The iOS-ification of Mac OS X has raised concerns in some corners, and while it’s clear that the future of these two operating systems is to become increasingly intertwined, I think that the fears that these two will become one are overblown—at least for now. WWDC 2011 seems poised to bring what a politician might call an era of “increased cooperation” to the two platforms.

Meanwhile parties have certainly already embraced the link between the two: see the Chameleon project, an attempt to make it easy to port apps from iOS to Mac OS X. Add to that the shared ecosystem of App Store and Mac App Store. and the message from Apple seems to be clear: if you’re a Mac developer, why aren’t you an iOS developer? If you’re an iOS developer, why aren’t you a Mac developer? Give it a try and you might just find that these are two great tastes that taste great together.