No ,they do not increases gathering speed. They just increases resource carrying capacity . To increase gathering speed here is following things you can do :-

1. Change runes to gathering 

2. Change talent 

3. Buy gathering speed boost for 24 hours from clan store or by gems .

Good points man. Also, research can help allot. And there is a bonus inside your own color. Not only that if you farm outside of your color you risk getting killed without the ability to heal your wounded troops in the hospital

Don't hesitate to ask if you have more questions. This game can be confusing af in the beginning

/Rag

thanks @danishmeraj2422 and @ragnarok  for clearing my doubt. even i thought same. Because when ever i send troops to gather it came all at the same time after gathering. 

game is confusing but really good game.