Behavioural individuality determines infection risk in clonal ant colonies

Area of Science:

• Social Insects
• Epidemiology
• Behavioral Ecology
• Parasitology

Background:

• Infection risk varies among individuals in social groups, influenced by behavior.
• Distinguishing behavioral effects on infection from other factors like age is challenging.
• Understanding disease dynamics in social systems requires integrating individual behavior and social structure.

Purpose of the Study:

• To investigate how individual behavioral variation influences infection risk and parasite transmission in clonal ant colonies.
• To determine the impact of nematode parasitism on ant physiology, behavior, and colony social organization.
• To explore the interplay between division of labor and parasite-driven changes in social structure.

Main Methods:

• Epidemiological experiments were conducted on clonal ant colonies.
• Analyses included chemical, transcriptomic, and automated behavioral tracking.
• Identical workers were used to isolate behavioral individuality as a source of variation.

Main Results:

• Caenorhabditis-related nematodes were identified as head parasites affecting ant survival and physiology.
• Behavioral differences among ants led to varied infection levels, linked to spatially organized division of labor.
• Infected ants exhibited altered behavior, remaining in the nest, which reduced colony-level division of labor.

Conclusions:

• Individual behavior is a critical determinant of infection risk and spread in social insect colonies.
• Parasites can manipulate host behavior to alter social organization, potentially enhancing transmission.
• The division of labor in ant societies shapes infection dynamics and is itself modulated by parasites.