Queen execution in a monogynous ant.

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Social Insect Behavior

Background:

• Workers in social insects can lay unfertilized eggs, leading to male offspring.
• This can create conflict over male parentage between queens and workers.
• Matricide (queen killing) by workers has been observed, primarily in specific colony structures or at the end of reproductive cycles.

Purpose of the Study:

• To investigate queen expulsion and matricide in a monogynous, monandrous ant species with perennial societies.
• To understand the fitness consequences for workers engaging in matricide.

Main Methods:

• Observational studies of ant colonies following hibernation.
• Recording instances of queen expulsion and matricide.
• Monitoring colony demographics (workers, brood) and reproductive output (male production).

Main Results:

• Workers aggressively expelled both related and unrelated queens shortly after hibernation.
• Queen expulsion and matricide significantly reduced worker and brood numbers.
• Worker direct fitness increased due to substantial male offspring production.
• Queens had short lifespans, while orphaned colony workers survived and reproduced males over years.

Conclusions:

• Matricide by workers can occur in monogynous, perennial ant societies.
• This behavior, despite initial colony reduction, enhances worker direct fitness by enabling male production.
• Worker-driven queen removal can be a strategy for reproductive gain in certain social insect systems.