Heat and Apis Mellifera - It is not commonly understood that Honey bee flight is sensitive to high air temperatures. While bees are known for their remarkable ability to thermoregulate or fanning to cool the hive, extreme heat can impair their activity and survival.
- Optimal flight temperature: 72°F to 95°F
- Reduced activity: Begins above 100–104°F
- Too hot for flight: Around 111–115°F
- High humidity also increases heat stress.
At these temperatures, bees risk overheating as their flight muscles can't stay cool enough to function properly. We commonly see bearding and behaviors like fanning and water collection, but what is not observed while happening is brood damage (needs optimal temps around 94F) Queens who stop laying, and possible colony failure simply do to a string of days with above average heat and humidity.
What can beekeepers do?
- Provide shade and water sources close to the hives. I've stapled insulation into my inner cover but we may place an light colored insulation board on top of the hive as well, or reflective insulation...still thinking about that.
- Avoid hive inspections during peak heat for your own safety as well as disrupting thermoregulation by the bees.
- Be mindful of your apiary locations for future reference in planning any move of the apiary.
This looks like swarming but it was a very hot day in 2024