if bees pollinate a heirloom pumpkin, can the seeds still be saved for next year? or are you supposed to hand pollinate those types yourselves?
That depends whether you're growing any other pumpkins or squash of that same species (or a close neighbor might be). If so, there is a risk of cross breeding, and it would be best to hand-pollinate* any flowers from which you intend to save seeds that will still be heirloom for next year. If not, it's okay to just let what happens happens and then save whatever seeds you want.
*To be pedantic again for the benefit of other readers, the operative thing here isn't whether the gardener pollinates, it's whether only the gardener pollinates. Just strolling up to an already-open female flower and pollinating it yourself does nothing to assure heirloom purity, because 900 bees have already visited it covered in who knows what pollen. When you're hand-pollinating with seed saving as a motive, you must seal off the female flower the night before it blooms, then remove the cover just long enough to pollinate it, and replace it again to be sure no bees contact it. To be 100% sure, you should pre-seal the male also.
