They have to have stores just to survive. They could have some stores left and be in a dearth or they could be out. But in a dearth the queen often doesn't lay even if there are stores.
In a dearth the bees are often consuming what they forage as quickly as they gather it, hence there are no resources for brood production. Also, as the bees go into a dearth they will eat the already layed eggs and larve and may even begin to cannabalize the newer (white) pupae. If you have more than one hive the bees will also begin robbing each other if you start feeding them individually. I usually feed both individually and with a feeding station when experiencing a dearth. The feeding station attracts the bees going out to forage so they concentrate on that, as well as using what is individually fed, and robbing doesn't happen. The main point is to place the feeding station as far from your hives as reasonably possible taking into consideration of property lines, building locations, etc.
In the mean time feed and be content with the fact that nature has provided you will the grand master of natural varroa control.