A novel interference behaviour: invasive wasps remove ants from resources and drop them from a height

Area of Science:

• Ecology
• Behavioral Ecology
• Invasive Species Biology

Background:

• Invasive species often disrupt native ecosystems through novel interactions.
• Competition for resources is a key driver of ecological interactions.
• Understanding interference behaviors is crucial for predicting invasion impacts.

Purpose of the Study:

• To document and analyze a novel interference behavior of the invasive wasp Vespula vulgaris towards the native ant Prolasius advenus.
• To investigate the relationship between competitor abundance and the frequency and efficiency of this interference behavior.

Main Methods:

• Direct observation and video recording of interactions at bait stations.
• Quantification of wasp-ant interactions and interference events.
• Analysis of the influence of ant abundance on wasp behavior.

Main Results:

• Vespula vulgaris was observed to remove Prolasius advenus workers using a unique 'ant-dropping' behavior.
• The frequency and efficiency of ant-dropping increased significantly with higher ant densities.
• Ant removals were the dominant interference strategy by wasps when ants were abundant.
• Intraspecific conflicts among wasps increased when ant presence was low.

Conclusions:

• Asymmetric body size and locomotion modes facilitate novel interference strategies in interspecific competition.
• The 'ant-dropping' behavior is an effective interference tactic for invasive wasps competing with native ants.
• This behavior highlights the complex ecological adjustments invasive species make to exploit resources in new environments.