Interesting. I have seen that reaction to bug attacks often. The first sting is treated as an anomaly, the second always registers as a mass attack requiring a quick change of venue. Wise to step off camera as the next thing you probably did was to check your shorts so to speak.
Ants are the bane of my existence here in Brazil. Our local jungle has over 400 species and some of them are quite aggressive. We have had them chop a 9 inch hole in a tent, cut down a hammock off a tree, tear big chunks out of a machete sheath, cut holes through a canvas bag, etc. I got a leg-full once through a hole in my pants at the knee.
There is a species that lives in our grasslands here that creates a large loose mound of dried leaf matter, usually hidden by tall grass. If you step into it you sink in to the shin and your entire foot will be covered with them. We had a student once slip off of a trail and crash down through a pile of debris held up by a fallen tree. We pulled him out and immediately started beating him to remove about 40 +/- large "Azteca" ants that had swarmed over him. It would have made classic video as he didn't know he was covered with ants and thought it was some sort of hazing for falling off the trail.