That's an interesting question. I've never seen it brought up. The named the whole first series of tests Gerboise with the colors (Blue, Red, etc.) designating individual shots.

As for why Gerboise... I've never seen anyone try to explain it. It is worth noting, however, that code names can be deliberately unmeaningful, or even when meaningful, can have their meanings forgotten. The first US test was dubbed "Trinity" and nobody really knows why. The first Soviet test was dubbed "RDS-1" and nobody really knows why. (In both cases there have been after-the-fact speculation as to what the names meant, but there isn't some document you can point to that says, oh, this was the intended symbolism.) The first UK test was Hurricane which I guess is fairly literal. The first Chinese test was "596" which is just a date (June 1959 — 59/6, when it was ordered). Sometimes US tests had really deliberate, meaningful names given to them, sometimes they were personal to the weaponeers, sometimes they were meaningless. So shot "Mike" was so-named because it was going to be in the megaton range (Mike is the phonetic alphabet for "M"). Shot "Dixie" was labeled with a "D" because it was a boosted bomb — deuterium. Shots "Ruth" and "Ray" were named after the godparents of the laboratory director. A lot of the later shot names were deliberately chosen at random from catalogs of names — there series where every shot is named after trees, or Native American tribes, etc.

So there might be a good reason for it — and there might not be.