The researchers measured the flight muscle temperatures, metabolism and water loss of honey bees carrying nectar inside a temperature-controlled flight room to determine the insects' ability to fly at high air temperatures. And, to determine how carrying nectar might change the flight behavior, the scientists also used high-speed videos of the flying bees to measure changes in how they flap their wings. Analysis of the high-speed videos of honey bees flying at air temperatures of 77 and 104 degrees showed that, at high body temperatures, bees apparently increase flight efficiency by lowering their wingbeat frequency and increasing stroke amplitude to compensate, reducing the need for evaporative cooling.

 

In other words, as temperatures rise, the bees change how they fly to decrease the heat they generate from metabolism, which helps these insects avoid overheating and save precious water. Due to the capacity of hot bees to reduce metabolic heat production during flight, the data suggest that, under dry and poor forage conditions, (dehydration) may limit activity before overheating, impairing critical pollination services provided by honey bees. Even with reductions in metabolic heat production, (dehydration) likely limits foraging at tempe ratures well below bees' critical thermal maxima in hot, dry conditions.Although the findings from this study relieve some concern about the impact of a warming climate on honey bees, there is still reason for worry as the world becomes warmer and drier.