Honeybees also use social distancing to protect themselves from pathogens

A new study found that honeybees, like humans, spread into the hive when exposed to a common parasite – and this can help them resist the outbreak.

Image credit: Boba Jaglicic.

When the COVID-19 pandemic first hit, the world became familiar with the words “social distancing.” Although the term is somewhat unfortunate (physical distance is probably better), it sent a clear message: staying further apart can help stop the spread of this virus.

This distancing approach has been reported several times in very different types of species, from baboons that keep themselves free of individuals with gastrointestinal infections, to ants infected with a pathogen that is referred to the edge of the anthill. Vampire bats, mandrills and guppies do too. Now, this type of behavior has been reported in honeybees for the first time.

“For several years, we have been researching the behavioral defenses that honeybees use to fight parasites and pathogens. We believe that this line of research can provide useful insights into improving the health status of honeybees, ”study author Alberto Satta told ZME Science. Satta works at the Dipartimento di Agraria, University of Sassari, Italy.

Bees are social creatures and they spend a lot of time huddled close together in the hive. They also have complex social structures that require them to share responsibilities. Previous research has suggested that bees may alter their social network to limit the spread of a pathogen, and researchers from the University of Sassari, Italy, wanted to see if they also practice social distancing.

The researchers analyzed how honey bees changed their parasite when exposed to the ectoparasite mite Varroa destructor – one of the most common and destructive parasites that bees can get.

Honey bee colonies are essentially divided into two main compartments: the inner, inhabited by the queen, fry and nurses, and the outer, occupied by foragers. This distribution protects the inner circle from exposure to uninvited guests or parasites, and there is limited interaction between the queen and the feeding animals that routinely exit the hive and are more exposed – hence they remain in the periphery.

This distribution becomes even more pronounced when bees are exposed to parasites. When a colony was exposed to a parasite, the outer circle moved even closer to the periphery, while the inner circle moved even closer to the center.

“Our study shows that honeybees can change their social organization in the presence of a parasite, suggesting a strategy implemented to mitigate the effects of parasitosis,” Satta explained in an email.

Main author Dr. Michelina Pusceddu, from the same university, said that this is a somewhat surprising but very effective adaptation.

“Their ability to adapt their social structure and reduce contact between individuals in response to a disease threat allows them to maximize the benefits of social interactions where possible and to minimize the risk of infectious diseases when necessary.

Developing this type of behavior takes a lot of time and is shaped by evolution, Satta adds.

“Social behaviors have evolved in animals as they increase reproductive success throughout life. In the case of honeybees and other social insects, the pattern of interactions between colony members across space and time has evolved under the need to ensure effective function, which selects close and interconnected communities and exposure to parasitic pressures that favor mechanisms that limit interactions between individuals in order to reduce the risk of disease spread. The balance between these two factors shapes the structure of social organization. “

Unfortunately for honey bees, they do not have access to the same defense mechanisms that we have – there is no face mask or vaccine for bees. However, bees can make their own medicine to protect themselves. Specifically, researchers are investigating the use of natural substances (propolis) with antimicrobial and anti-parasitic properties as a means of counteracting the Varroa destructor mite.

“We assumed that bees can engage in self-medication against this parasite by using the propolis they produce in the hive. Recently, we have obtained evidence that this drug induces beneficial effects on parasitized bees, prolongs their life, and that it “has a negative effect on the condition of the mite. An additional paper on these topics will be published soon,” concludes Satta.

The study was published in The progress of science.

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