Social environment affects the transcriptomic response to bacteria in ant queens.

Area of Science:

• Social insect immunity
• Behavioral ecology
• Innate immune response

Background:

• Social insects utilize individual immunity and social immunity for colony defense against pathogens.
• Social immunity involves collective behavioral and organizational disease defenses.

Purpose of the Study:

• To investigate how social context (presence or absence of workers) affects individual immunity in ant queens after bacterial infection.
• To analyze gene expression patterns in ant queens to understand the interplay between infection and social environment.

Main Methods:

• Bacterial infection of ant queens (Linepithema humile) with either a bacterial mix or control solution.
• Queens were reared with or without workers.
• Gene expression analysis using RNA-sequencing at multiple time points post-injection.

Main Results:

• Social isolation affected metabolism gene expression but not immune gene expression in queens.
• Infected queens, with or without workers, up-regulated similar numbers of innate immune genes, activating Toll, Imd pathways, and melanization.
• Queens in different social contexts regulated different specific genes within these pathways and showed distinct overall gene expression patterns.

Conclusions:

• The absence of workers does not impede the initiation of an individual immune response in ant queens.
• The social environment significantly influences the specific pathways and gene regulation patterns of the innate immune response in queens.