Were the giant ants in Indiana Jones & the Kingdom Of The Crystal Skull a tribute to the movie THEM! ?
Both were set in 1950 era. Both involved giant ants.
And old movies have lots of fans.
I don’t think so. Them! didn’t have a swarm and the ants in Kingdom of the Crystal Skull were not giant since ants really can get to be an inch or more in length (warning: depicts very large ant crawling on someone for scale).
Phase IV had lots of swarming ants… and they were smart! 
I caught that crapfest on a Saturday afternoon on channel 5 in LA, and the ending bit with the guy in the pit full of holes, then the ants pouring out- :eek: !
Phase IV was a perfectly good movie, with some very interesting points made.
Them! is a classic, but I don’t see how the ants in IJatKotCS bear any relation to it.
The ants are exaggerated versions of siafu, a real-life ant species (although not one native to South America).
Each installment of the franchise has included a set of creepy crawlies. Raiders: snakes and tarantulas, Temple: assorted insects and the “feast”, Crusade: rats (and snakes again, briefly).
Given the location (S.A.) and the fact that they were one of the more obvious creepy crawlies not yet used, ants just seemed like an obvious choice. In fact, if there’s a 1954 movie it’s referencing, it’s not Them! so much as this.