Re: pollinating services for pumpkins
2 acres on pumpkins is not a mono-crop, the bees will forage everything else they can find in the afternoon once the pumpkin blossoms close.
We grow pumpkins and to be honest we haven't seen any benefit to pollinating with honey bees. We didn't have bees on them in 2010 and did in 2011... the crop size increased, but the pumpkins were all smaller in 2011... weight wise we came out about the same. This year we are going to keep the bees on them, but pinch off some of the blossoms to try and boost pumpkin size.
Always question Conventional Wisdom.