Ants kill infected colony members
Ants kill infected colony members to protect their colonies from an epidemic outbreak when they have failed to prevent transmission of the deadly disease. This is the conclusion reached by researchers at the Institute of Science and Technology Austria (IST) http://ist.ac.at in their latest publication, published in the journal "eLife".
According to the scientists, ant colonies show a strong resemblance to the immune system that protects the bodies of vertebrates when it comes to this type of disease control.
If an ant comes into contact with the pathogenic fungus Metarhizium, for example, it becomes a threat to the entire colony. An infection spreading among ants living in close proximity could mean the extinction of the colony if the disease cannot be contained.
Cleaning and grooming as the first line of defence
The researchers had previously shown that ants of the invasive species Lasius neglectus intensively clean and groom colony members when pathogenic fungal spores are present on their bodies. This reduces the risk of the fungus penetrating the body and infecting the animal. If the fungus cannot be combated by conventional means, however, only one option remains. When infected brood is involved, the response to an actual fungal infection is more radical: in a series of experiments, the researchers found that ants kill immobile pupae in order to interrupt the pathogen’s life cycle and prevent it from spreading further.
Early intervention protects the colony
The ants act selectively. Using chemical disease cues, they detect animals that are already fatally infected and eliminate them. “Colony members are able to smell and isolate sick individuals at an early stage of the infection process. They then carry out what we call ‘destructive disinfection’: killing both the fungus and the diseased animal to prevent the pathogen from becoming infectious and spreading to nestmates,” says IST research director Sylvia Cremer. This approach, she notes, has many parallels to the immune system of vertebrates. Find out more about fascinating wildlife and education at wildbeimwild.com.
