Hi! This is Adriana, the beekeeper from South Mountain Bees.
I didn't know what a nectar dearth was until I became a beekeeper. A nectar dearth is a period when there are little to no flowers that produce nectar. Nectar is what bees transform into delicious honey, and it is their main source of carbohydrates, so beekeepers are very aware of dearth periods. We all know that in cold climates there are hardly any flowers in the winter, but there is also a Summer dearth between Spring flowers and Fall flowers, when it is dry and hot. Sometimes the Summer dearth comes accompanied by a drought, and then there will be no Fall flowers for bees to forage on until the next Spring.
The problem of the lack of nectar flowers is that it will encourage robbing. Strong colonies will see weaker colonies as a source of food, and they will deplete their stores. Bees fight to death protecting their colony, and even their queen may be killed. In the middle of a robbing episode the smell of honey will invite other predators such as wasps and hornets to take advantage of a colony who's overwhelmed by the attack. Even strong colonies can be the target of robbing. Several smaller colonies may simultaneously attack a strong colony outnumbering them.
One of the reasons a colony is weak, is that it's infested with parasites and viruses, and those will be taken along with the honey, creating a serious situation in the robbing colony by importing disease, and not just honey.
Here's how you can help.
Consider adding more Summer flowers to your garden. It will look great, besides helping feed our flying friends. My favorite Summer blooming plants are cone flowers (echinacea), although the groundhogs also like them... blue lobelia (lobelia siphillitica), and balloon flowers (platycodon grandiflorus).
Other July-August blooming plants include borage (borago officinalis), catnip (nepeta cataria), dahlia (dahlia pinnata), panicled hydrangea (hydrangea paniculata) (the one in the picture), joe-pye weed (eutrochium purpureum), lemon balm (melissa officinalis), oregano (origanum vulgare), peppermint (mentha piperita), poppies (papaver), rosemary (salvia rosmarinus), and shiso (perilla frutescens), which blooms from July to October!