Can I pick a flower from my pumpkin plant and save it for future hand pollination?

Grasshoppers are devouring every new flower that shows up on my pumpkin plants. I was hoping to pick a flower and keep it for pollination when the opposite sex flower opens. If it is possible to do this, how would I keep the flower safe? How long can I keep it for it to still be viable? Does anyone have any reliable resources or links they could send me to learn more?