Study: How do honey bees protect themselves from high temperatures?

A recent study showed that honey bees, while carrying nectar, have an amazing ability to adjust their flight behavior to avoid increasing their body temperature when air temperatures rise, by reducing the frequency of their wing beats and increasing the wing beat amplitude. The study aimed to determine the extent to which rising air temperatures affect the ability of honey bees to search for nectar.

The study conducted on western honey bees indicates that the researchers measured the temperatures of the bees’ flight muscles, metabolism, and the extent to which honey bees that carry nectar lose water. These experiments were conducted inside a temperature-controlled flight chamber to determine the insects’ ability to fly at high air temperatures. .

To determine how a nectar carrier might change flight behavior, the scientists also used high-speed videos of flying bees to measure changes in how they flap their wings before and after warming.

He showed bees flying at an air temperature estimated at 40 degrees Celsius. that its average wing beat frequencies and metabolic rates during flight and produce metabolic heat; Less than bees that fly at an estimated temperature of 25 degrees Celsius.

The researchers also found that flight muscle temperatures increased linearly with the presence of excess weight on the bee from nectar loads at air temperatures of 20 or 30 degrees Celsius, but what is striking is that there was no change in muscle temperature with increasing nectar loads at In the air temperature of 40 °C, nectar-laden flying bees were able to avoid overheating at 40 °C by reducing metabolic rates during flight, and increasing evaporative cooling when their body temperature rose.

This was clearly demonstrated when analyzing high-speed videos of honeybees flying at high air temperatures, as the bees appeared to increase flight efficiency by lowering the frequency of their wingbeats and increasing the wingbeat amplitude to compensate for the translational force, reducing the need for cooling by evaporating water. from the body, which may lead to dehydration.

How do large insects regulate their temperature?

Large flying insects can regulate their temperature to a great extent, but their body temperatures usually continue to rise as the outside air temperature rises.

Higher body temperatures can reduce insect foraging and flight times, or even kill insects. So most insects avoid heat stress by changing the time of day they are active. However, many social insects, including honey bees, must remain active regardless of heat stress, to ensure colony growth and survival. Some insects can also cool their bodies by evaporating water to avoid heat stress, but this may lead to dehydration.

Here comes this method of heat regulation, which the study focused on, as many insect species can avoid high temperatures by reducing their wing beat frequencies and thus reducing metabolic heat production when flying at high air temperatures.

This last behavioral strategy reduces the risk of dehydration, but reducing wingbeat frequency without changing other aspects of wing kinematics will reduce the insect's aerodynamic lift and mechanical energy generation, and limit its ability to transport large amounts of nectar and pollen to the hive, so the bee besides reducing Wingbeats increase the amplitude of the stroke.

High-resolution video imaging showed that bees flying at an air temperature of 40°C had a higher average wingbeat amplitude than bees flying at 25°C, increasing translational force generation. Thus bees were able to carry the same total mass (body mass plus nectar load) when flying at different temperatures by adjusting two basic movements: wingbeat frequency and stroke amplitude.

What is the effect of drought on honey bees?

Although the results of this study show that bees can avoid the damage of a warming climate by reducing metabolic heat production during flight, the problem of drought may cause unavoidable damage.

Data indicate that in conditions of dry and poor pastures, drought may limit bee activity, which reduces the important pollination services that bees provide to plants, and drought also limits the ability of bees to search for food and nectar.

What is the danger of diminishing insect accessories?

It should be noted that insect pollinators, such as honeybees, are one of the most important means of pollinating plants, and their decline represents a major threat to plant growth.

It is no secret that insect pollinators are declining at an alarming rate, and one of the reasons for this is climate change . Repeated and increasingly intense climate events, such as global warming and heat waves, may push insect pollinators - including bees - away from their thermal limits, potentially leading to the decline of these pollinators.

If insect pollinators continue to decline, we will likely see catastrophic impacts on ecosystems and human agriculture that rely heavily on the services these organisms provide.