The most dangerous parasites of bees, the Varroa mite, is constantly evolving, while bee populations are faced with harsher and harsher environmental conditions, aside from this fierce foe. According to a recent study, the small deadly mite can easily infiltrate itself into beehives because it can change the chemical alignment on its skin in order to smell like the bees do.
The Varroa mite is extremely damaging to the bees, not only through its own actions, but because it is a very potent vector for viral diseases of bees. The Varroa mite is an ectoparasite, which means that it lives on the skin of the bees.
It feeds on hemolymph from the bees and therefore, the consequences are strictly dependent on the number of Varroa mites attacking one bee and the development state of the bee when facing the mites.
When it feeds on adult bees, the parasite can penetrate the outer layer of the bee and engage in feeding and it causes the bee a local wound at the bite site. Therefore, if there are several mites present on one bee, then the injuries that they will inflict will be quite serious.
Moreover, if several mites feed on a bee’s hemolymph, this will most likely weaken it considerably, thus making it hard to bare the physical wounds sustained at the bite site. The immature bees are the ones who are in grave danger when facing Varroa mites, because several parasites can easily kill them.
The Varroa mite is a particularly important vector in the transmission of many viral diseases of bees. The most dangerous viruses are the Chronic Paralysis Virus, the Black Queen Cell Virus and the Sac Brood Virus, that have devastating effects on bee populations.
The first virus to be associated with the presence of the vicious mite was the Acute Paralysis Virus, that only succeeded in reaching the bees through the mites. Then, as the presence of the mites became more and more important, other dangerous viruses made their way into bee hives, such as the Deformed Wing Virus which renders adult bees unable to fly.
Quite a few of these viral diseases have a similar route of transmission, as they get inoculated in the bee’s hemolymph when the mite feeds and then they replicate there in great numbers.
What the most recent study revealed is just how easy the Varroa mites can adapt when transferred from the Western honey bee, Apis mellifera to the Asian honey bee, Apis cerana, and vice versa. It seems that the tactic it uses is creating a chemical camouflage so as to smell like the bee and thus make their way safely into the beehive.
The lead author of this recent Varroa study, Michigan State University Entomologist, Zachary Huang, believes that it only takes the mites two or three days to change its chemical outline and therefore its smell. The exact chemical measurements in the experiment were conducted eight days after the mite was placed in the new environment.
This study was published in the scientific journal Biology Letters. Its lead author has thus expressed his worries in regards to the White House’s goal of reducing bee mortality by 15%. He feels that it will be precisely the deadly little Varroa parasites that will prevent this goal from being achieved.
At the moment, there is no cure for the viral diseases that bees are fighting. Therefore, the only means of protecting them is making sure that they do not come in contact with the Varroa mites, that transmit the diseases.
Unfortunately, this is becoming more and more difficult, as the parasites are becoming resistant to the common preventative measures used against them. This is why further research on the matter bares great importance for saving the bees and with them, the entire environment.
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