Hi,

  In my search service application crawling is happening but the scopes are empty. Not sure why. Any idea?

Hi SPAdmin,

According to your post my understanding is you scope is empty but crawling is happening. I would suspect that this is related to permission issue. Check the account permission level. 

If my suggestion is not working please let us know

Thanks for the reply, but permission of which account yu meant by that. For populating scope what extra permission is required?

Here you go

http://sharepoint.stackexchange.com/questions/5150/why-do-crawls-work-but-scope-contains-0-items

https://nickhadlee.wordpress.com/2011/07/24/no-search-results-for-contextual-scopes/

Hello,

You might also want to look at this thread:

http://sharepoint.stackexchange.com/questions/51084/search-scope-shows-empty-add-rules