You sure the smell is coming from the shower? I had a similar smell which I thought was coming from the shower but it actually turned out to be the toilet. I had to replace the wax ring.
Honestly, you should probably have a professional come out and take a look at them. I know it's more expensive, but anytime you've got ants inside of a void area and there appears to be even minor structural damage, it's best to get an idea of what's been going on. I do pest control in the Pacific Northwest, and you guys down in Texas have some crazy-ass bugs compared to what we have here...but to have somebody come look at it shouldn't be too exorbitantly expensive. P.S. - go local if you have a pro come look. Industry-wide, local companies are better acquainted with the pests in the area and give better quality service. I know, there are exceptions to everything, but that's what I've found. Good luck.
Thats kinda hard to describe the smell but its strong ever after we bleached the walls and carpet. (yes the carpet has bleached spots now, oh well) Everytime it rains the smell gets stronger and actually now that I think about the ants come in too. There is mold growing upward on the outisde of the building and I think on wet days it grows faster and started growing inward to the inside of the apartment. Obviously a hole somewhere though if massive ants are getting in to escape the rain Every now and then we go inside the room to do mediocre cleaning and we can smell it through clothing (covering our noses) and the Lysol doesn't hide the smell I'd buy like 2 gallons of store brand Bleach (GV cost like 97 cents I think) and poor it all at once. Is that allowed?? Or would that be enviromentally unsafe. Goodness. I hate that camera vid of the drain.