Under its influence, bees are trying to secretly enter neighboring colonies.
American biologists have discovered that the Israeli acute paralysis virus (IAPV), which infects bees, can change their behavior in such a way that workers begin to fly out of their hive and try to secretly enter neighboring colonies. An article with the research results was published in the scientific journal Proceedings of the National Academy of Sciences.
“The most interesting result of our observations is that infection with the IAPV virus increases the likelihood that individuals carrying it will be accepted into foreign bee colonies. They somehow bypass the attention of the hive guards, which usually does not happen among bees, commented one of the study authors, professor at the University of Illinois at Urbana-Champaign Adam Dolezal.
Over the past 20 years, biologists have discovered many examples of how parasites have learned to manipulate the behavior of their hosts and even directly control their actions. The most interesting and advanced example of such "puppeteers" is considered to be fungi from the genus Ophiocordyceps, which turn tropical ants into "zombies".
This parasite completely takes control of the nervous system of insects, forcing them to attach to the branches and leaves of trees that are located directly above the nests. Further observations showed that Ophiocordyceps have different programs of action, which are activated after the infection of different species of ants and testing their brains for compatibility before "zombification".
Professor Dolezal and his colleagues found that an equally advanced arsenal of tools that can be used to manipulate the behavior of bees very flexibly and widely was found to be characteristic of the widespread Hymenoptera pathogen, the IAPV virus. Infection with this virus causes the bees to quickly lose mobility and die, which can kill the entire hive.
Invisible puppeteer
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Beekeepers and biologists have long noticed that insects infected with IAPV often behave in very strange ways in the early stages of the disease. They forget their way home after collecting nectar and fly not to their hive, but to neighboring bee colonies. In the case of apiaries, this often leads to the rapid spread of the virus throughout their territory.
American biologists have tried to understand why such "forgetfulness" of bees is connected by attaching special beacons to the abdomen of several hundred insects. With their help, scientists tracked the movements and social interactions of workers.
These observations revealed an even more bizarre shift in the behavior of infested insects. On the one hand, if they were inside their hive, then they relatively rarely interacted with other individuals, which is quite normal for sick bees. On the other hand, if they approached the entrance to someone else's colony, their behavior changed dramatically.
In this case, as scientists found, sick insects tried to actively contact with working individuals who guarded the approaches to the hive, feeding them and interacting with them in other ways. All this, paradoxically, led to the fact that the "guards" very often let infected bees into their hive, allowing the virus to spread in the new habitat.
How exactly this process proceeds, scientists cannot yet say, however, they suspect that the unexpected docility of the colony's guards is due to the fact that the virus in a special way changes the set of pheromones that the worker bees produce. This is supported by the fact that the individuals in whom scientists simulated the development of infection by stimulating the activity of their immunity did not arouse special sympathy for the "guard" of the hive, unlike real IAPV carriers.
Further study of this virus, scientists hope, will help them uncover all the changes in the bee behavior program that it produces. Their analysis, in turn, will allow us to understand how to protect apiaries from IAPV and other viruses similar to it, which often cause massive death of bees and force workers to leave the colony en masse and leave the queen.