Safe distancing in the animal kingdom

Reporter : Xu Yue / Publisher : China Science News via ScienceNet

Ref : http://news.sciencenet.cn/htmlnews/2020/8/444200.shtm 

Translation, editing : Gan Yung Chyan, KUCINTA SETIA

With the global spread of SARS-CoV-2, "social distance" has become one of the hot words this year. However, according to a study recently published in "Proceedings of the Royal Society B", humans are not the only animals that leave space between individuals to reduce the spread of disease. In the animal kingdom, such as lobsters, bees, etc., examples of avoiding infection by maintaining social distance are common.

One of the authors of the above study, Dana Hawle,Virginia, USA, Dana Hawle, a biologist at the Polytechnic Institute in Virginia, US, said, "The best example we call 'isolation' comes from social insects such as ants and bees. In some cases, infected insects will leave the colony and die alone." 

Andrea Townsend, a behavioral ecologist at Hamilton College, one of the authors of the study, added that in the above-mentioned types of insect communities, the relationships between individuals are closer than those in the human family. Therefore, it is the most advantageous behavior to sacrifice oneself to protect the extended family.

So, how do animals judge when to maintain safe distancing?

In this regard, Townsend said that some animals (such as house sparrows) use certain behaviors such as sleepiness as clues to assess potential infections and avoid contact with infected individuals.

"In other cases, animals have evolved to be able to sense quite complex cues to maintain social distance." Hawle cites examples such as Caribbean spiny lobster (a social lobster that usually lives in groups), which can detect sick lobster urine in order to avoid the area occupied by these diseased lobsters.

Another example is a baboon. The researchers took animal feces with and without parasites and placed a small portion of them on the side of the tree. They found that feces without parasites are more attractive to primates than those with parasites.

How do researchers judge that these animals are safe distancing because of illness and not other reasons?

There are several ways to find out the cause of these behaviors. "In wild animals, a simple and feasible method is to treat infected individuals with drugs to remove parasites, and then observe whether the avoidance behavior in the community changes." Hawle said that researchers have done similar experiments on baboons and found that , The parasitized individuals will be avoided by the group. Once the infected individuals receive treatment, they will start combing each other's hair again.

Hawle pointed out that researchers have also done a lot of research on ants. They introduced a fungal pathogen into the colony, and then compared the behavioral response of the control colony introduced in the aqueous solution. "If you see that the behavior of the ant colony has changed (restricting activities in the nest or spending more time outside the nest) in order to avoid pathogens, it is a strong proof that these animals have responded to the fungus itself."

An important takeaway from the above research is that social distance will work. "Anytime, when we see a behavior evolving again and again in unrelated animals, it is a signal. Although social distance is a costly behavior, the benefits obviously outweigh the costs," Hawle said.

Related paper information: https://doi.org/10.1098/rspb.2020.1039