Difficult to diagnose. Reduced flight, defensive bees, and colonies not developing appropriately for spring and/or summer season. Heavy colony number of bees competing for too few resources.
Bee colonies need sufficient fresh nectar and pollen resources to expand populations in the spring, provide energy to construct and maintain nests, store sufficient stores for winter (and for beekeeper harvest), and to rear fat fall bees to survive winter. A dearth in pollen or nectar can occur if bee colonies are overstocked in an area or there are insufficient pollen- and nectar-producing sources. Such insufficiencies can be temporarily related to environmental conditions such as too much or too little rain, for example, or high or low temperatures reducing forager behavior.
Plants need favorable temperatures and environmental conditions to produce pollen and nectar for bee forage. Some locations have a poor nectar flow or pollen availability. Crop plantings in bloom might be good food resources for bees, but when not in bloom are often deserts with no or poor nectar or pollen available as forage.
Carbohydrate in the form of sugar syrup or protein can be fed as a supplement, but bees do better on natural nectar and pollen resources. Bee colonies can become overly defensive (aggressive) during nectar dearth and may decrease in size when pollen resources are not adequate.
During the spring, the colony experiences dramatic population increase and may exhaust their winter stores. Thus, they may be “on the edge,” living each day on what is collected the previous day. Likewise, big, fully expanded colonies may lack sufficient nectar resources to continue to collect and store nectar as honey, especially with heavy competition from other colonies if, e.g., the forage area is over-saturated with colonies, or there is a lack of adequate flowering plants due to dry or wet weather, or heavy agricultural use of surrounding land. These situations can lead to poor foraging conditions in which bees cannot collect the pollen and nectar resources the colony needs.
Weak colonies due to other causes: reduced adult population leading to reduced coverage of brood in spring and summer due to swarming of colony; a queen event; pesticide poisoning; or other common occurrences
Burlew R. 2023 update. How to recognize a nectar dearth & safeguard your bees. Honey Bee Suite. Accessed 2023. https://www.honeybeesuite.com/how-to-recognize-a-nectar-dearth/
Melanie. 2021. What Is Summer Nectar Dearth (What To Do For Your Bees). Beekeeping for Newbies. Accessed 2023. https://www.beekeepingfornewbies.com/nectar-dearth/
Huang Z. 2018. Feeding honey bees. MSU Extension Bulletin E-3369: 1-3. https://pollinators.msu.edu/sites/_pollinators/assets/File/FeedingHoneyBees-Final.pdf
