Blame it All on Charlton Heston

Just so you know, there is nowhere in Central America any deadly species of local ants that at any time may have served as inspiration for maras, the name mostly associated nowadays with the violent, criminal gangs that for the last several years have threatened the stability of regional governments.
For that matter, there isn’t either an anthill that devours everything, as proclaimed in that other hyperlinked news story.
Mara — the plural, maras, is used when talking about the gangs — is indeed shortened from marabunta but before the early 1950s, when it appears to have been first used in the movie The Naked Jungle, the term was not widely known in the region.
It was an Austrian-born short-story writer who first came up with the tale about a legion of killer ants swiftly devouring everything on its path.

Esquire magazine's issue with the story
[The Nostalgia League website]

The writer, Carl Stephenson, never used the term in the English version of the story first published in Esquire magazine back in 1938.
As you will read in The Nostalgia League, “Leiningen versus the Ants” is “one of the most famous short adventure stories ever written” and “a favorite of most radio buffs,” since it was dramatized in more than one occasion in Escape.
Leiningen’s character in the radio show was played by William Conrad, the — ahem, portly — actor whom many will probably remember better as the star of the TV series Cannon.
Conrad, who later in the film starring Eleanor Parker and Charlton Heston would play the government agent, is the man who first uttered the famous word “marabunta.”
When Heston and Donna Reed, as his wife, played a new radio dramatization of the Stephenson short story — apparently as part of the promotion for the release of The Naked Jungle — on the Lux Radio Theater, marabunta was also used as the name for the rampaging ants — you can hear the actor playing the government agent [not Conrad, by the way] at about 20:40 in the youtube recording.
It was movie-lovers and broadcast radio buffs in the United States who first got familiar with the name marabunta. You can even find comments online about then-young aficionados to the radio dramas of the 50s scaring their peers with the threat of “marabunta!” on camping trips.

Marabunta: Charlton Heston on the radio

The Naked Jungle was not initially a success but with Heston’s stature as an actor enhanced after his roles both in The Ten Commandments (1956) and Ben-Hur (1959), the movie — released in Spanish as either “Marabunta!” or “Cuando ruge la marabunta” (When the Marabunta Roars) — became better known and appreciated by movie fans in Spanish-speaking countries.
It was in the early 60s then that marabunta became part of colloquial Spanish — by that I mean not sanctioned by the Royal Spanish Academy (RAE) — in eastern El Salvador.
“They are a plague of 'chapulines' (locusts)!,” was — and still is — how people in my country would refer to any group of young people raiding the food and drinks at a social gathering.
“No, chapulines no! We are marabunta!,” the members of the raiding party would then say, with no amount of contrition or shame in their reply.
The shortening to mara — as a synonym for gang or posse — would come later, though it would take years of internal armed conflict for the term to be associated with extorsion, rapes, murder and plenty other criminal behavior.
None of that can be blamed on Charlton Heston, of course, though you may certainly charge him with the popularity that the term acquired.