Do S2 cells normally have small 1-2um objects floating in culture? - (Feb/07/2014 )

I thawed and started growing an S2 cell culture one week ago and the cells are growing slowly and are forming clusters. Also there are small 1-2um spherical objects co-culturing with the cells. I'm thinking that these small structures are contamination and explain the slow cell growth. However, I've never grown this type of cell before. So my question is whether it is normal to find these smaller spherical structures in S2 cell culture? Thanks for any help.

Fruitfly, 

If possible, try uploading pictures of your culture. People find it easier to comment on something that they can see. :)