Ants avoid superinfections by performing risk-adjusted sanitary care

Area of Science:

• Social Immunity
• Animal Behavior
• Disease Ecology

Background:

• Social animals benefit from communal care, but caregivers risk infection.
• Sub-clinical infections can alter an individual's immune susceptibility to future pathogens.
• This altered susceptibility may impact the caregiver's future disease-preventing behaviors.

Purpose of the Study:

• To investigate if altered disease susceptibility in ant caregivers affects their sanitary care behavior.
• To determine how ants respond to infection risk from homologous versus heterologous pathogens.
• To examine the flexibility of social immunity in response to individual infection history.

Main Methods:

• Used ants and fungal pathogens as a model system to study social immunity.
• Exposed caregiver ants to low-dose infections (homologous and heterologous pathogens).
• Observed and quantified changes in grooming and antimicrobial disinfection behaviors.

Main Results:

• Low-level infections provided protection against homologous pathogens but increased mortality from heterologous pathogens.
• Ants reduced grooming and increased antimicrobial disinfection when caring for nestmates with heterologous pathogens.
• This behavioral adjustment reduced the acquisition of heterologous pathogen particles and subsequent superinfection.

Conclusions:

• Ants flexibly adjust their sanitary care behaviors based on their infection history and perceived risk.
• Risk-adjusted social immunity allows ants to mitigate the impact of novel pathogen exposure.
• Demonstrates a sophisticated capacity for individual risk assessment and collective behavioral adaptation in disease prevention.