Conducting research on energy loss in beehive and its effect on varroa mite
What is the effect of using insulated beehive on Spring development or how it lowers the need for energy, was described in more detail in another article about our research about energy loss and its effect on honey production and we do not want to repeat here.
The type of beehive has no effect on the presence of varroa mite. However, it is important how well it reproduces in it
We are convinced that wood beehives that are widely used in Europe, gave varroa a warm welcome. Advocates of wood beehives will most probably stop reading here. We strongly recommend reading this section in full, or potentially go back and read the article by swiss researchers about varroa reproduction cycle.
What does it have to do with temperature inside the beehive?
Everything evolves from the duration of bee development, which directly depends on the beehive inside temperature which depends on the insulating feature of the beehive.
"The brood hatches flawless, despite developing at 32°C, but for a worker bee the time needed extends from 21 up to 22-26 days."
Čavojský et al., 1981, p.61
From the varroa reproduction cycle article it is clear what is the reproductive potential of a varroa male, how many female varroa there are in a cell ready to mate. At the temperature of 34,5°C the male varroa manages to mate with one female, however there are 4-5. After the bee hatches, his chances for further mating are over.
Now the problem is when due to insufficient insulation of the beehive, the colony is unable to maintain the 34,5°C in all parts of brood chamber. Of course, bees hatch but it takes them longer and here is the catch. Extending the time larva and pupa spend under the cap, this increases the reproductive potential of male varroa which then manages to mate with more than only one female. If he manages to mate with two females, his effectiveness has gone up by 100%, with three … etc. There is no need for an extensive research here, a single digital thermometer with a sensor inside the capped brood gives us a lot of insight already. In case of colder weather, if the colony is placed in a wood beehive or otherwise poorly insulated beehive and on the top of it, if it is a weaker colony, the brood chamber temperature goes down to even 30°C. The male varroa has plenty of time to mate with multiple females.
Reinvasion or reinfection
We think that the case of reinvasion (reinfection) of varroa mite is a case of poor beehive insulation. We have discovered there is less than 34°C after performing many brood nest temperature checks. It is notable on brood nest edges or in case of colder weather, in wood beehives also in the middle. This extends the time a worker bee pupa spends capped and this very extension is significant for reproductive potential of male varroa which causes an exponential increase of varroa mites in the colony, that beekeepers refer to as reinvasion. It is in fact a result of poor beehive insulation, giving varroa more space to breathe and he has happily taken it.
In general, late brood rearing in wood beehives could be considered an advantage by assuming “late brood rearing, less varroa reproduction cycles”. We do not conform to this assumption and it is valid only if we cannot treat for varroa and drastically reduce its population in Spring.
There are a few main factors which together make up a deadly cocktail for a bee colony which result in catastrophic colony collapses. Obviously, one shall know them all or almost all. However, it is most important to know those particular ones which beekeepers can influence and really do something about it.
Using insulated beehives and keeping varroa infestation low reliably (i.e. using Varroa Terminator) allows a profitable beekeeping without the risk of colony collapse over winter.
HiveTD beehive with its construction and used materials ensures a great degree of thermal insulation. The loss of energy is minimized to the lowest level, so that bee development is happening in standard durations without high energy demands to keep required inside temperature and without temperature oscillation because of weather conditions.
ČAVOJSKÝ, Valent a kol. 1981. Včelárstvo. [Beekeeping] Bratislava : Príroda, vydavateľstvo kníh a časopisov, n.p., 1981. p. 628.