Mass graves are just part of the job for the glamorous hostess

Desirable but not available: the smiling geishas in micro-minis

They are inescapable: lovely Latinas who outline their broad, red smiles with dark lip-liner, so that they look like mouths in a child's colouring book, then toss back manes of shiny hair that nearly reach the hems of their matching micro-minis. They giggle together, but eventually emerge to pass out flyers or stickers, or guide visitors to their seats before an exposition gets under way.

They are inescapable: lovely Latinas who outline their broad, red smiles with dark lip-liner, so that they look like mouths in a child's colouring book, then toss back manes of shiny hair that nearly reach the hems of their matching micro-minis. They giggle together, but eventually emerge to pass out flyers or stickers, or guide visitors to their seats before an exposition gets under way.

Edecanes they are called, and these carefully groomed beauties fill a special slot in the Mexican glamour stakes; somewhere between cheerleaders, hostesses and models. The word comes from the term aide-de-camp, and no self-respecting Mexican business or political party would hold an event without them.

Even the Methodist Church advertised to hire edecanes for a recent Mexico City convention. Presumably these girls were not flummoxed by the usual edecan quandaries of how to keep a sash bearing the sponsor's name legible while still revealing enough cleavage.

Macho patrons and clients expect assistants to be female, young and decorative ... but not necessarily available.

Carla and Cecilia, both 23 and busty, insist that they won't countenance demands for sex or dates. They are thrilled to be hired for a car-agency opening out in Edomex, just beyond the capital. They wear baseball caps with the company logo at identical jaunty angles and teeter on stiletto heels that leave pockmarks in the showroom floor. In many ways, their role is as traditionally Mexican as, say, a mariachi trumpeter in silver-studded trousers. A quintet of mariachi musicians in embroidered sombreros is tuning up in the corner near a shiny Chevy Suburban, and the girls tap their red-varnished talons in time to the beat.

What distinguishes the edecanes from models is that they are expected to be not only well spoken and flirty but informed: almost a sort of Mexican geisha. Carla tells me she answered an agency advert that caught her eye because it required "excellent presentation and ability to dominate a situation" but also stressed that "neither speaking English nor stature is important". Carla's beauty is undeniable ­ sculpted cheekbones and almond eyes the colour of black coffee ­ but she is too tiny to make it as a runway model. She's barely five feet tall. As a fledgling edecan she brings home nearly £1,000 a month ­ enough to encourage her to continue letting her face make her fortune at fairs and expos, at least until she nears the age of 30.

Several years ago, a scandal broke when several top edecanes in Congress, young women who normally pass out documents or serve coffee, were said to be moonlighting as prostitutes.

Cecilia mused: "Some girls must be tempted, of course. You get cute uniforms and good contacts in this business, and you can take it from there. But we come from good families. Other girls envy us. It's fun, not nasty. We are supposed to animate things."

Edecanes do turn up in the oddest places, from church halls to concert halls. Perhaps the most memorable were the teams of girls hired by the Mexican Prosecutor General's office to help to manage swarms of press near the Texas border. An FBI informant was showing police where to dig in an attempt to find the bodies of victims murdered by local drug barons on some isolated ranches. Statistics indicated that hundreds could be buried. Foreign correspondents and relatives of missing Mexicans quickly descended on the border near Juarez. There was no doubt they'd reached the Mexican side of the frontier when they encountered smiling young 20-somethings in brief skirts, gesturing helpfully and calling out: "This way to the mass graves!"