A HIVE FOR SUPPRESSION OF MITES AND VIRAL DISEASES IN BEES

 

It is now well known that mite infestations and associated viral diseases are the second leading cause of bee mortality worldwide, after pesticide poisoning. Thermal methods for controlling mites within the hive are also known: heating the brood to temperatures incompatible with mite population growth.

 

Scientists, while studying the effects of temperature on mites, have identified five factors affecting temperature on all forms of mite development—from eggs to adult mites.

 

• The first factor—exposure to temperatures in the range of +36-38°C (96-100°F) on mite egg masses—destroys from 50% to 95% of the egg masses. Temperatures above +38°C (100°F) kill them all. This significantly reduces the rate of mite population growth.

• The second factor is the increased impact of elevated temperatures on mite egg-laying in drone brood. They were found to be more sensitive to temperature increases than egg-laying in bee brood. The decline in the mite population growth rate may accelerate, as drone brood is a favorite breeding ground for mites during the growth of bee colonies.

• The third factor is that scientists have proven that increasing the temperature in bee brood cells to 37°C (98°F) dramatically reduces the fertility of female mites by almost 2.5 times. This is due to physiological problems in female mites: egg-laying is delayed, eggs die, and the females themselves die too. It is believed that the cause of their death is their particular vulnerability when ready to lay eggs.

• The fourth factor—and we observed this during our research—is a significant decrease in the number of drone brood on the periphery of the nest. The reason for this is likely that if the hive temperature is elevated, there are no places where the temperature would be conducive to the establishment of drone brood, and the presence and quantity of drone brood are among the main factors in the explosive development of mites during bees' colony growth.

• The fifth factor is the increased effect of elevated temperatures on unfertilized mite eggs, which the female lays first, directly under the lid of a sealed cell. The combs are heated by air, meaning they begin with the cell lids, and the mites are the first to lose a male to reproduce. Therefore, even if some females survive and emerge from the cells, they will be sterile for at least another cycle. This will also reduce the rate of mite population growth.

 

Until now, all methods for creating such conditions have been either technically complex, or ineffective, or expensive. We have created our Sunny Hive as cheap and simple as possible. It has no electronics or mechanics, and it requires no electricity or internet connection. This simplifies and reduces the cost, but also places a certain responsibility on the beekeeper.

 

Testing results and several years of use in three apiaries demonstrated its effectiveness in controlling Varroa mites. The percentage of mite infestations in colonies kept in Sunny Hives, without the use of chemicals throughout the active season, typically does not exceed 1-4% by the end of the season. If the infestation is higher in an individual colony, a single treatment with amitraz will restore it to normal condition. Thus, in three apiaries in different regions, groups of 10 colonies were kept without any treatments throughout the active season and with virtually no treatments at the end. This was repeated for at least three seasons. Some colonies were kept under these conditions for four seasons. All colonies were used equally with the rest of the apiary for honey collection, queen production, and offshoots production. There were no colony losses in Sunny Hives during these years. At the same time, colony losses occurred in standard hives across all apiaries, despite repeated treatments with organic acids and amitraz.

 

We have repeatedly conducted safety studies of Sunny Hives for bees and developed recommendations for beekeepers on how to use them. Research has shown that queens, bees, brood, and the combs itself in small colonies of 4-6 frames with young combs are most sensitive to overheating. Normal, complete colonies suffer significantly less. Research has shown that when the air in the hive warms to 43-45°C (113-119°F), queens can die or be damaged. Research has shown that brood suffers significantly less. Larvae and pupae can withstand high temperatures and die only in areas with air temperatures of 45-50°C (113-122°F), which can occur near the south wall of the hive and in its upper part.

 

These results have led us to develop instructions for hive users. The basic idea of ​​these instructions is that the hive will effectively combat mites without harming the bees, provided the outside temperature is between 24-28°C and bright sun. However, when the outside temperature reaches 29°C or higher and there is bright sun, the hive should be covered with shields or completely shaded. This will prevent overheating of the queen and brood. If such conditions are short-lived, the shields or shading can be removed again. If such conditions persist for a long time (for example, during the onset of the hot season), the hive should be completely switched to maximum shading mode, and the solar heating elements should be blocked or removed.

 

In southern and Mediterranean climates, the primary periods for the hive to suppress Varroa mite development are considered to be autumn, winter, and spring, before the onset of summer heat. During the hot season, the mites, exposed to high temperatures created by nature itself, reduce or stop their development. Cooler seasons, however, allow them to actively grow their population, relying on the active development of bee colonies after the summer temperatures drop. It is precisely this process that the Sunny Hive should suppress in southern climates. And this is entirely possible.