Social network - the factor that makes Tasmanian devil in danger of extinction

New research on the Tasmanian devil's social network may help prevent the spread of a disease that threatens to make the species extinct. The results of the study published in Ecology Letters suggest that there exists a network of complex relationships between devil individuals, explaining why the disease can spread rapidly in this single-pocketed mammal.

The Tasmanian devil (Tasmania's "demon" island) is the largest carnivorous mammal in the world, but they are facing the risk of extinction because of a strange type of cancer infecting tumors in the region. face (DFTD). Devil is a species that often lives alone, researchers believe that the disease spreads through bites when they eat around a prey and through the mating process.

The team led by Rodrigo Hamede from the University of Tasmania, used radio rings to detect the Tasmanian devil's communication structure, helping to understand exposure situations that spread disease among individuals. in species.

'Tracking contact between individuals in a wild animal is very difficult, especially those living in the forest and working at night,' Hamede said. "However, this is very important to understand the social, disease transmission in a species as well as to find the necessary epidemiological models."

Previous studies on Tasmanian devil populations have encountered many limitations due to lack of field observation, and due to the difficulty of understanding the specific mating process of this species which occurs underground. .

The team attached radio signals to adult devils at Narawntapu National Park, a 25-square-kilometer area containing demons that have never been infected.The signal ring is attached to a total of 46 mature devil individuals including 23 males and 23 females.

'Tasmanian devils demon'. (Photo by Mike Lehmann, Wikimedia Commons )

This signal cycle will record when, and for how long the two male devils, the close contact. The downloaded data will indicate the frequency of contact between individuals.

'Understanding the contact network is important because often there are only a small number of individuals with a large frequency of exposure and these' super-contact 'individuals are the culprits for most of the spread. of disease, ' Hamede said. 'Once these individuals are identified, measures such as direct or isolation treatment can help control the disease.'

The obtained data reveals that although the devil is a single living species, all individuals are connected to a social network, in other words all the tracking devils are connected to the children. rest. This explains why DFTD disease can spread easily throughout the entire devil population.

As expected, some individuals play a very active role in the network - they are 'super-exposed ' individuals. At the same time, contact between female devils seems more frequent among males, since males often deliberately avoid touching each other.

While it is thought that the devil is a random intercourse, the data this time show that there is a priority relationship between some male male pairs - something that is shown by a male's long-term protection for a child. This is another risk of disease transmission through prolonged exposure.

'The first phase of transmission is the contact between an infected individual and a high-risk individual,' Hamede concludes . 'Radio signal rings allow us to measure the frequency of exposure at this stage. In fact, all individuals are associated with a single network, which means that the disease can spread to any individual in the herd when an individual is infected. . '