Bees become less active during certain times of the year, prompting questions about their whereabouts. Their seasonal behavior reflects life cycle strategies to survive scarcity or harsh conditions, varying by species and environmental challenges.
Understanding Seasonal Bee Behavior
Bees become less visible as seasons change, especially when temperatures drop and floral resources diminish. This shift in activity is tied to external factors like temperature, humidity, and food availability.
While most species are active in spring and summer, they prepare for colder months as fall approaches, decreasing foraging flights. This seasonal pattern helps them persist when food is scarce.
Honey Bees: Winter Survival Strategies
Honey bees employ a collective strategy to survive winter, unlike many other insects that enter a state of dormancy. When temperatures fall below approximately 50-57°F (10-14°C), a honey bee colony forms a “winter cluster” inside its hive. This cluster is a tight ball of bees where they generate and conserve heat.
Worker bees vibrate flight muscles to produce warmth, maintaining a core temperature of 90-97°F (32-36°C). Outer bees insulate, while inner bees rotate to access stored honey for energy. The queen stays warm, and her egg-laying reduces or ceases. The colony uses 30 to 60 pounds of honey reserves over winter to fuel this heat.
Bumble Bees and Solitary Bees: Different Overwintering Methods
Bumble bees and solitary bees have distinct overwintering strategies that differ significantly from those of honey bees. For bumble bees, the entire colony, including the workers and male drones, perishes with the arrival of cold weather. Only the new, fertilized queen survives the winter.
These queens find sheltered locations, such as small cavities just below the soil surface, under leaf litter, in woodpiles, or within rock walls, where they enter a state of hibernation. In spring, these queens emerge, establish new nests, and begin laying eggs to start a new colony.
Solitary bees, the majority of bee species, do not maintain a colony through winter; adults typically die. Their offspring overwinter as larvae or pupae in individual nests (tunnels, hollow stems, or burrows). Mothers provision them with “bee bread” (pollen and nectar) to sustain their development. They remain dormant until emerging as adults the following spring or summer.
Beyond Winter: Other Reasons for Reduced Bee Activity
While winter is a primary reason for reduced bee activity, other environmental factors can also make bees less visible at various times of the year. Adverse weather conditions, such as heavy rain, high winds, and extreme temperatures, directly impact their foraging behavior. Heavy rainfall can restrict foraging, make flight challenging, and wash away nectar, limiting food availability.
High winds also significantly reduce foraging efficiency, making it harder for bees to fly, navigate, and take off from flowers. Foraging rates decrease by about 15% in moderate wind speeds and can stop entirely in winds exceeding 25 mph (40 km/h).
Conversely, extremely hot temperatures, especially above 95°F (35°C), can cause heat stress, leading bees to reduce or cease foraging during the hottest parts of the day. They may prioritize collecting water to cool their hives through evaporative cooling.