An invasive ant species able to counterattack marabunta raids

Area of Science:

• Ecology
• Behavioral Ecology
• Invasive Species Biology

Background:

• The invasive ant Pheidole megacephala (big-headed ant) is found in the Neotropics.
• Army ants like Eciton burchellii and Eciton hamatum are native predators in this region.

Purpose of the Study:

• To investigate the defense mechanism of Pheidole megacephala against army ant raids.
• To understand how chemical cues mediate interactions between invasive and native ant species.

Main Methods:

• Observational studies of ant interactions in the field.
• Bioassays using water-based techniques to analyze chemical transfers.
• Cuticular hydrocarbon analysis to identify transferred compounds.

Main Results:

• Pheidole megacephala counterattacked Eciton army ant raids.
• Returning Eciton workers were attacked by their own colony mates, mistaking them for prey.
• Chemical compounds from Pheidole megacephala were transferred to Eciton workers, disrupting their colony recognition.
• The zone of conflict shifted away from the Pheidole nest, protecting the colony.

Conclusions:

• Pheidole megacephala employs a unique defense strategy by inducing friendly fire in invading army ants.
• This defense is a byproduct of the invasive ant's aggressive nature and not a result of coevolution.
• The chemical camouflage prevents recognition of returning colony members, effectively neutralizing the threat from Eciton ants.