Dug Up An Ant Bed!

Question
I adopted/rescued (Yep. Adopted. From Petsmart on one of their adoption days.) a 10 month old Aussie on Sunday (just a few days ago). She is very obedient; she will sit and stay on command (I practice this with her every chance I get--especially because I can tell by certain looks whether she is going to sit or whether she is focused on something completely different) and she is potty-trained.

Well, today I figured I'd buy her some toys, being that she is playful and I figured she MUST be getting bored by just pouncing on me as 'play time' and playing 'tag'.

I bought a frisbee, a toy rope thing, and a tennis ball (she loves them all) and what gets me is that we were testing out what she can do and can't do with the frisbee when all of a sudden...(in mid play, mind you)
she begins to chew on some grass protruding from an ant hill. She's done this before so I wasn't all too surprised--until she began to dig at the ant bed.
She didn't stop until there was a crater left and the ants were biting her (which I did attend to).

Now, I was reading that Aussies do get bored easily because they do need an abundant amount of playtime. I was just wondering if maybe she dug it up because;
while she was chewing on the grass an ant had begun to bite her and she just got annoyed with it.

Because to be quite honest..I've read some destructive things Aussies can do when bored and this terrifies me.

Now, I'm assuming (because right now she's lying at the side of my bed--I took her digging as a sign of disrespect of my property and can't let her up here until I feel I'm the pack leader again) it is because an ant had bitten her and she wanted to find out what the heck was biting her.

(Oh PLEASE tell me she isn't getting bored and destructive--I mean, I play with her for hours at a time [atleast 2 a day] and she has full run of the backyard when nobody is home. :( )

Also--she whimpered a bit when she started dislodging the ant bed (of course, she was being bitten to hell!) so how certain can I be that she won't try to dig that ant bed again? I'm afraid to come home to a seriously ant-injured dog.

Answer
Tegan,  
    Not to worry!!  Sounds to me like all normal behavior for a 10 month old pup.  Australian Shepherds, which are an American creation, are high energy type dogs with lots of "prey drive".
This means they are always on the lookout for something to chase, catch, herd, dig up or otherwise harass. This is all pretty much "regular" stuff for any pup worth his salt.
    It sounds like you're doing an excellent job with your dog.  Lots of exercise and attention.   Keeping her outdoors when you're not home is also a very good idea.  When she does come in, make it a training session of sorts, she'll learn her  manners fast this way.
Don't forget crate training.  All dogs need to learn this one.  As long as you keep up with consistent, firm discipline your pack leader status is secure.  Relax & enjoy her.  Let her dig up some ants and eat some dirt.  This is how she learns.  She probably has enough spunk to route an ornery old cow if she put her mind to it.  I just love these type of dogs!! Seeing as you got her from a "rescue", she has probably already been spayed.  If she's not, don't do it now.  Good Luck Tegan,  Thanks for asking, Rob