spraying for weeds

Roundup is toxic to bees, but is way down on the list of products. It didn't make the highly toxic, nor the mildly toxic lists. It is listed on the relatively non-toxic list. I would remove any and all blooms in the area to be sprayed, then spray at or very near night. Also, most labels now are written with the honeybee in mind, so be sure and follow the label directions explicitly and I don't think you will have any problem.

http://ohioline.osu.edu/hyg-fact/2000/2161.html

They won't eat much.

I don't worry too much about the little sugar ants. They usually go away when you quit feeding.