[Ropster]

I have some in my greenhouse in full flower, but no insects(except ants) will they fruit ?

[Trillium]

You'll have to play the part of resident bee, unfortunately. While strawberries are self fertile, they can't easily transfer pollen without the help of wind or bees. You could keep both ends of the greenhouse open (if you have such), or allow bees to come into your greenhouse. But most dependable is taking a Q tip (cotton swab) and dabbing pollen among all the flowers. It's a bit of work but the only way to get a crop.

[sunshineband]

They do need pollination -- try a soft piece of cotton wool if you have no bees make their way into your greenhouse  

[Ivah]

You'll be able to tell if you and the insects haven't managed it as you'll get distorted fruit.