Pathogen Prevalence Modulates Medication Behavior in Ant Formica fusca

Area of Science:

• Behavioral Ecology
• Insect Pathology
• Social Immunity

Background:

• Social insects like ants face high pathogen transmission risks due to colony structure.
• Ants have evolved behavioral and physiological strategies to combat pathogens, including self-medication.
• Formica fusca ants previously demonstrated self-medication against fungal pathogens using hydrogen peroxide.

Purpose of the Study:

• To investigate how disease prevalence in Formica fusca colonies affects the strength of their self-medication response.
• To explore the plasticity of self-medication behavior in response to varying pathogen exposure levels.

Main Methods:

• Colonies of Formica fusca were exposed to a fungal pathogen, with either half or all workers affected.
• Different dietary combinations, including hydrogen peroxide-supplemented food, were offered to the ants.
• Ant foraging behavior on control versus medicinal food was observed in relation to infection status and colony disease prevalence.

Main Results:

• Formica fusca workers exhibit self-medication behavior even at low lethal pathogen doses.
• The intensity of the self-medication response is significantly influenced by the prevalence of disease within the colony.
• Uninfected ants also consumed hydrogen peroxide food, suggesting potential for kin medication in partially infected colonies.

Conclusions:

• Ants possess a notable capacity for self-medication against fungal infections.
• Self-medication behavior in ants demonstrates plasticity, adapting to disease prevalence.
• Further research is needed to understand the role of self-medication in broader social immunity strategies.